1 // SPDX-License-Identifier: Apache-2.0 OR MIT 1 // SPDX-License-Identifier: Apache-2.0 OR MIT
2 2
3 //! API to safely and fallibly initialize pinn 3 //! API to safely and fallibly initialize pinned `struct`s using in-place constructors.
4 //! 4 //!
5 //! It also allows in-place initialization of 5 //! It also allows in-place initialization of big `struct`s that would otherwise produce a stack
6 //! overflow. 6 //! overflow.
7 //! 7 //!
8 //! Most `struct`s from the [`sync`] module ne 8 //! Most `struct`s from the [`sync`] module need to be pinned, because they contain self-referential
9 //! `struct`s from C. [Pinning][pinning] is Ru 9 //! `struct`s from C. [Pinning][pinning] is Rust's way of ensuring data does not move.
10 //! 10 //!
11 //! # Overview 11 //! # Overview
12 //! 12 //!
13 //! To initialize a `struct` with an in-place 13 //! To initialize a `struct` with an in-place constructor you will need two things:
14 //! - an in-place constructor, 14 //! - an in-place constructor,
15 //! - a memory location that can hold your `st 15 //! - a memory location that can hold your `struct` (this can be the [stack], an [`Arc<T>`],
16 //! [`UniqueArc<T>`], [`Box<T>`] or any othe 16 //! [`UniqueArc<T>`], [`Box<T>`] or any other smart pointer that implements [`InPlaceInit`]).
17 //! 17 //!
18 //! To get an in-place constructor there are g 18 //! To get an in-place constructor there are generally three options:
19 //! - directly creating an in-place constructo 19 //! - directly creating an in-place constructor using the [`pin_init!`] macro,
20 //! - a custom function/macro returning an in- 20 //! - a custom function/macro returning an in-place constructor provided by someone else,
21 //! - using the unsafe function [`pin_init_fro 21 //! - using the unsafe function [`pin_init_from_closure()`] to manually create an initializer.
22 //! 22 //!
23 //! Aside from pinned initialization, this API 23 //! Aside from pinned initialization, this API also supports in-place construction without pinning,
24 //! the macros/types/functions are generally n 24 //! the macros/types/functions are generally named like the pinned variants without the `pin`
25 //! prefix. 25 //! prefix.
26 //! 26 //!
27 //! # Examples 27 //! # Examples
28 //! 28 //!
29 //! ## Using the [`pin_init!`] macro 29 //! ## Using the [`pin_init!`] macro
30 //! 30 //!
31 //! If you want to use [`PinInit`], then you w 31 //! If you want to use [`PinInit`], then you will have to annotate your `struct` with
32 //! `#[`[`pin_data`]`]`. It is a macro that us 32 //! `#[`[`pin_data`]`]`. It is a macro that uses `#[pin]` as a marker for
33 //! [structurally pinned fields]. After doing 33 //! [structurally pinned fields]. After doing this, you can then create an in-place constructor via
34 //! [`pin_init!`]. The syntax is almost the sa 34 //! [`pin_init!`]. The syntax is almost the same as normal `struct` initializers. The difference is
35 //! that you need to write `<-` instead of `:` 35 //! that you need to write `<-` instead of `:` for fields that you want to initialize in-place.
36 //! 36 //!
37 //! ```rust 37 //! ```rust
38 //! # #![allow(clippy::disallowed_names)] 38 //! # #![allow(clippy::disallowed_names)]
39 //! use kernel::sync::{new_mutex, Mutex}; 39 //! use kernel::sync::{new_mutex, Mutex};
40 //! # use core::pin::Pin; 40 //! # use core::pin::Pin;
41 //! #[pin_data] 41 //! #[pin_data]
42 //! struct Foo { 42 //! struct Foo {
43 //! #[pin] 43 //! #[pin]
44 //! a: Mutex<usize>, 44 //! a: Mutex<usize>,
45 //! b: u32, 45 //! b: u32,
46 //! } 46 //! }
47 //! 47 //!
48 //! let foo = pin_init!(Foo { 48 //! let foo = pin_init!(Foo {
49 //! a <- new_mutex!(42, "Foo::a"), 49 //! a <- new_mutex!(42, "Foo::a"),
50 //! b: 24, 50 //! b: 24,
51 //! }); 51 //! });
52 //! ``` 52 //! ```
53 //! 53 //!
54 //! `foo` now is of the type [`impl PinInit<Fo 54 //! `foo` now is of the type [`impl PinInit<Foo>`]. We can now use any smart pointer that we like
55 //! (or just the stack) to actually initialize 55 //! (or just the stack) to actually initialize a `Foo`:
56 //! 56 //!
57 //! ```rust 57 //! ```rust
58 //! # #![allow(clippy::disallowed_names)] 58 //! # #![allow(clippy::disallowed_names)]
59 //! # use kernel::sync::{new_mutex, Mutex}; 59 //! # use kernel::sync::{new_mutex, Mutex};
60 //! # use core::pin::Pin; 60 //! # use core::pin::Pin;
61 //! # #[pin_data] 61 //! # #[pin_data]
62 //! # struct Foo { 62 //! # struct Foo {
63 //! # #[pin] 63 //! # #[pin]
64 //! # a: Mutex<usize>, 64 //! # a: Mutex<usize>,
65 //! # b: u32, 65 //! # b: u32,
66 //! # } 66 //! # }
67 //! # let foo = pin_init!(Foo { 67 //! # let foo = pin_init!(Foo {
68 //! # a <- new_mutex!(42, "Foo::a"), 68 //! # a <- new_mutex!(42, "Foo::a"),
69 //! # b: 24, 69 //! # b: 24,
70 //! # }); 70 //! # });
71 //! let foo: Result<Pin<Box<Foo>>> = Box::pin_ 71 //! let foo: Result<Pin<Box<Foo>>> = Box::pin_init(foo, GFP_KERNEL);
72 //! ``` 72 //! ```
73 //! 73 //!
74 //! For more information see the [`pin_init!`] 74 //! For more information see the [`pin_init!`] macro.
75 //! 75 //!
76 //! ## Using a custom function/macro that retu 76 //! ## Using a custom function/macro that returns an initializer
77 //! 77 //!
78 //! Many types from the kernel supply a functi 78 //! Many types from the kernel supply a function/macro that returns an initializer, because the
79 //! above method only works for types where yo 79 //! above method only works for types where you can access the fields.
80 //! 80 //!
81 //! ```rust 81 //! ```rust
82 //! # use kernel::sync::{new_mutex, Arc, Mutex 82 //! # use kernel::sync::{new_mutex, Arc, Mutex};
83 //! let mtx: Result<Arc<Mutex<usize>>> = 83 //! let mtx: Result<Arc<Mutex<usize>>> =
84 //! Arc::pin_init(new_mutex!(42, "example: 84 //! Arc::pin_init(new_mutex!(42, "example::mtx"), GFP_KERNEL);
85 //! ``` 85 //! ```
86 //! 86 //!
87 //! To declare an init macro/function you just 87 //! To declare an init macro/function you just return an [`impl PinInit<T, E>`]:
88 //! 88 //!
89 //! ```rust 89 //! ```rust
90 //! # #![allow(clippy::disallowed_names)] 90 //! # #![allow(clippy::disallowed_names)]
91 //! # use kernel::{sync::Mutex, new_mutex, ini 91 //! # use kernel::{sync::Mutex, new_mutex, init::PinInit, try_pin_init};
92 //! #[pin_data] 92 //! #[pin_data]
93 //! struct DriverData { 93 //! struct DriverData {
94 //! #[pin] 94 //! #[pin]
95 //! status: Mutex<i32>, 95 //! status: Mutex<i32>,
96 //! buffer: Box<[u8; 1_000_000]>, 96 //! buffer: Box<[u8; 1_000_000]>,
97 //! } 97 //! }
98 //! 98 //!
99 //! impl DriverData { 99 //! impl DriverData {
100 //! fn new() -> impl PinInit<Self, Error> 100 //! fn new() -> impl PinInit<Self, Error> {
101 //! try_pin_init!(Self { 101 //! try_pin_init!(Self {
102 //! status <- new_mutex!(0, "Drive 102 //! status <- new_mutex!(0, "DriverData::status"),
103 //! buffer: Box::init(kernel::init 103 //! buffer: Box::init(kernel::init::zeroed(), GFP_KERNEL)?,
104 //! }) 104 //! })
105 //! } 105 //! }
106 //! } 106 //! }
107 //! ``` 107 //! ```
108 //! 108 //!
109 //! ## Manual creation of an initializer 109 //! ## Manual creation of an initializer
110 //! 110 //!
111 //! Often when working with primitives the pre 111 //! Often when working with primitives the previous approaches are not sufficient. That is where
112 //! [`pin_init_from_closure()`] comes in. This 112 //! [`pin_init_from_closure()`] comes in. This `unsafe` function allows you to create a
113 //! [`impl PinInit<T, E>`] directly from a clo 113 //! [`impl PinInit<T, E>`] directly from a closure. Of course you have to ensure that the closure
114 //! actually does the initialization in the co 114 //! actually does the initialization in the correct way. Here are the things to look out for
115 //! (we are calling the parameter to the closu 115 //! (we are calling the parameter to the closure `slot`):
116 //! - when the closure returns `Ok(())`, then 116 //! - when the closure returns `Ok(())`, then it has completed the initialization successfully, so
117 //! `slot` now contains a valid bit pattern 117 //! `slot` now contains a valid bit pattern for the type `T`,
118 //! - when the closure returns `Err(e)`, then 118 //! - when the closure returns `Err(e)`, then the caller may deallocate the memory at `slot`, so
119 //! you need to take care to clean up anythi 119 //! you need to take care to clean up anything if your initialization fails mid-way,
120 //! - you may assume that `slot` will stay pin 120 //! - you may assume that `slot` will stay pinned even after the closure returns until `drop` of
121 //! `slot` gets called. 121 //! `slot` gets called.
122 //! 122 //!
123 //! ```rust 123 //! ```rust
124 //! # #![allow(unreachable_pub, clippy::disall 124 //! # #![allow(unreachable_pub, clippy::disallowed_names)]
125 //! use kernel::{init, types::Opaque}; 125 //! use kernel::{init, types::Opaque};
126 //! use core::{ptr::addr_of_mut, marker::Phant 126 //! use core::{ptr::addr_of_mut, marker::PhantomPinned, pin::Pin};
127 //! # mod bindings { 127 //! # mod bindings {
128 //! # #![allow(non_camel_case_types)] 128 //! # #![allow(non_camel_case_types)]
129 //! # pub struct foo; 129 //! # pub struct foo;
130 //! # pub unsafe fn init_foo(_ptr: *mut fo 130 //! # pub unsafe fn init_foo(_ptr: *mut foo) {}
131 //! # pub unsafe fn destroy_foo(_ptr: *mut 131 //! # pub unsafe fn destroy_foo(_ptr: *mut foo) {}
132 //! # pub unsafe fn enable_foo(_ptr: *mut 132 //! # pub unsafe fn enable_foo(_ptr: *mut foo, _flags: u32) -> i32 { 0 }
133 //! # } 133 //! # }
134 //! # // `Error::from_errno` is `pub(crate)` i 134 //! # // `Error::from_errno` is `pub(crate)` in the `kernel` crate, thus provide a workaround.
135 //! # trait FromErrno { 135 //! # trait FromErrno {
136 //! # fn from_errno(errno: core::ffi::c_in 136 //! # fn from_errno(errno: core::ffi::c_int) -> Error {
137 //! # // Dummy error that can be const 137 //! # // Dummy error that can be constructed outside the `kernel` crate.
138 //! # Error::from(core::fmt::Error) 138 //! # Error::from(core::fmt::Error)
139 //! # } 139 //! # }
140 //! # } 140 //! # }
141 //! # impl FromErrno for Error {} 141 //! # impl FromErrno for Error {}
142 //! /// # Invariants 142 //! /// # Invariants
143 //! /// 143 //! ///
144 //! /// `foo` is always initialized 144 //! /// `foo` is always initialized
145 //! #[pin_data(PinnedDrop)] 145 //! #[pin_data(PinnedDrop)]
146 //! pub struct RawFoo { 146 //! pub struct RawFoo {
147 //! #[pin] 147 //! #[pin]
148 //! foo: Opaque<bindings::foo>, 148 //! foo: Opaque<bindings::foo>,
149 //! #[pin] 149 //! #[pin]
150 //! _p: PhantomPinned, 150 //! _p: PhantomPinned,
151 //! } 151 //! }
152 //! 152 //!
153 //! impl RawFoo { 153 //! impl RawFoo {
154 //! pub fn new(flags: u32) -> impl PinInit 154 //! pub fn new(flags: u32) -> impl PinInit<Self, Error> {
155 //! // SAFETY: 155 //! // SAFETY:
156 //! // - when the closure returns `Ok( 156 //! // - when the closure returns `Ok(())`, then it has successfully initialized and
157 //! // enabled `foo`, 157 //! // enabled `foo`,
158 //! // - when it returns `Err(e)`, the 158 //! // - when it returns `Err(e)`, then it has cleaned up before
159 //! unsafe { 159 //! unsafe {
160 //! init::pin_init_from_closure(mo 160 //! init::pin_init_from_closure(move |slot: *mut Self| {
161 //! // `slot` contains uninit 161 //! // `slot` contains uninit memory, avoid creating a reference.
162 //! let foo = addr_of_mut!((*s 162 //! let foo = addr_of_mut!((*slot).foo);
163 //! 163 //!
164 //! // Initialize the `foo` 164 //! // Initialize the `foo`
165 //! bindings::init_foo(Opaque: 165 //! bindings::init_foo(Opaque::raw_get(foo));
166 //! 166 //!
167 //! // Try to enable it. 167 //! // Try to enable it.
168 //! let err = bindings::enable 168 //! let err = bindings::enable_foo(Opaque::raw_get(foo), flags);
169 //! if err != 0 { 169 //! if err != 0 {
170 //! // Enabling has failed 170 //! // Enabling has failed, first clean up the foo and then return the error.
171 //! bindings::destroy_foo( 171 //! bindings::destroy_foo(Opaque::raw_get(foo));
172 //! return Err(Error::from 172 //! return Err(Error::from_errno(err));
173 //! } 173 //! }
174 //! 174 //!
175 //! // All fields of `RawFoo` 175 //! // All fields of `RawFoo` have been initialized, since `_p` is a ZST.
176 //! Ok(()) 176 //! Ok(())
177 //! }) 177 //! })
178 //! } 178 //! }
179 //! } 179 //! }
180 //! } 180 //! }
181 //! 181 //!
182 //! #[pinned_drop] 182 //! #[pinned_drop]
183 //! impl PinnedDrop for RawFoo { 183 //! impl PinnedDrop for RawFoo {
184 //! fn drop(self: Pin<&mut Self>) { 184 //! fn drop(self: Pin<&mut Self>) {
185 //! // SAFETY: Since `foo` is initiali 185 //! // SAFETY: Since `foo` is initialized, destroying is safe.
186 //! unsafe { bindings::destroy_foo(sel 186 //! unsafe { bindings::destroy_foo(self.foo.get()) };
187 //! } 187 //! }
188 //! } 188 //! }
189 //! ``` 189 //! ```
190 //! 190 //!
191 //! For the special case where initializing a 191 //! For the special case where initializing a field is a single FFI-function call that cannot fail,
192 //! there exist the helper function [`Opaque:: 192 //! there exist the helper function [`Opaque::ffi_init`]. This function initialize a single
193 //! [`Opaque`] field by just delegating to the 193 //! [`Opaque`] field by just delegating to the supplied closure. You can use these in combination
194 //! with [`pin_init!`]. 194 //! with [`pin_init!`].
195 //! 195 //!
196 //! For more information on how to use [`pin_i 196 //! For more information on how to use [`pin_init_from_closure()`], take a look at the uses inside
197 //! the `kernel` crate. The [`sync`] module is 197 //! the `kernel` crate. The [`sync`] module is a good starting point.
198 //! 198 //!
199 //! [`sync`]: kernel::sync 199 //! [`sync`]: kernel::sync
200 //! [pinning]: https://doc.rust-lang.org/std/p 200 //! [pinning]: https://doc.rust-lang.org/std/pin/index.html
201 //! [structurally pinned fields]: 201 //! [structurally pinned fields]:
202 //! https://doc.rust-lang.org/std/pin/inde 202 //! https://doc.rust-lang.org/std/pin/index.html#pinning-is-structural-for-field
203 //! [stack]: crate::stack_pin_init 203 //! [stack]: crate::stack_pin_init
204 //! [`Arc<T>`]: crate::sync::Arc 204 //! [`Arc<T>`]: crate::sync::Arc
205 //! [`impl PinInit<Foo>`]: PinInit 205 //! [`impl PinInit<Foo>`]: PinInit
206 //! [`impl PinInit<T, E>`]: PinInit 206 //! [`impl PinInit<T, E>`]: PinInit
207 //! [`impl Init<T, E>`]: Init 207 //! [`impl Init<T, E>`]: Init
208 //! [`Opaque`]: kernel::types::Opaque 208 //! [`Opaque`]: kernel::types::Opaque
209 //! [`Opaque::ffi_init`]: kernel::types::Opaqu 209 //! [`Opaque::ffi_init`]: kernel::types::Opaque::ffi_init
210 //! [`pin_data`]: ::macros::pin_data 210 //! [`pin_data`]: ::macros::pin_data
211 //! [`pin_init!`]: crate::pin_init! 211 //! [`pin_init!`]: crate::pin_init!
212 212
213 use crate::{ 213 use crate::{
214 alloc::{box_ext::BoxExt, AllocError, Flags 214 alloc::{box_ext::BoxExt, AllocError, Flags},
215 error::{self, Error}, 215 error::{self, Error},
216 sync::Arc, 216 sync::Arc,
217 sync::UniqueArc, 217 sync::UniqueArc,
218 types::{Opaque, ScopeGuard}, 218 types::{Opaque, ScopeGuard},
219 }; 219 };
220 use alloc::boxed::Box; 220 use alloc::boxed::Box;
221 use core::{ 221 use core::{
222 cell::UnsafeCell, 222 cell::UnsafeCell,
223 convert::Infallible, 223 convert::Infallible,
224 marker::PhantomData, 224 marker::PhantomData,
225 mem::MaybeUninit, 225 mem::MaybeUninit,
226 num::*, 226 num::*,
227 pin::Pin, 227 pin::Pin,
228 ptr::{self, NonNull}, 228 ptr::{self, NonNull},
229 }; 229 };
230 230
231 #[doc(hidden)] 231 #[doc(hidden)]
232 pub mod __internal; 232 pub mod __internal;
233 #[doc(hidden)] 233 #[doc(hidden)]
234 pub mod macros; 234 pub mod macros;
235 235
236 /// Initialize and pin a type directly on the 236 /// Initialize and pin a type directly on the stack.
237 /// 237 ///
238 /// # Examples 238 /// # Examples
239 /// 239 ///
240 /// ```rust 240 /// ```rust
241 /// # #![allow(clippy::disallowed_names)] 241 /// # #![allow(clippy::disallowed_names)]
242 /// # use kernel::{init, macros::pin_data, pin 242 /// # use kernel::{init, macros::pin_data, pin_init, stack_pin_init, init::*, sync::Mutex, new_mutex};
243 /// # use core::pin::Pin; 243 /// # use core::pin::Pin;
244 /// #[pin_data] 244 /// #[pin_data]
245 /// struct Foo { 245 /// struct Foo {
246 /// #[pin] 246 /// #[pin]
247 /// a: Mutex<usize>, 247 /// a: Mutex<usize>,
248 /// b: Bar, 248 /// b: Bar,
249 /// } 249 /// }
250 /// 250 ///
251 /// #[pin_data] 251 /// #[pin_data]
252 /// struct Bar { 252 /// struct Bar {
253 /// x: u32, 253 /// x: u32,
254 /// } 254 /// }
255 /// 255 ///
256 /// stack_pin_init!(let foo = pin_init!(Foo { 256 /// stack_pin_init!(let foo = pin_init!(Foo {
257 /// a <- new_mutex!(42), 257 /// a <- new_mutex!(42),
258 /// b: Bar { 258 /// b: Bar {
259 /// x: 64, 259 /// x: 64,
260 /// }, 260 /// },
261 /// })); 261 /// }));
262 /// let foo: Pin<&mut Foo> = foo; 262 /// let foo: Pin<&mut Foo> = foo;
263 /// pr_info!("a: {}", &*foo.a.lock()); 263 /// pr_info!("a: {}", &*foo.a.lock());
264 /// ``` 264 /// ```
265 /// 265 ///
266 /// # Syntax 266 /// # Syntax
267 /// 267 ///
268 /// A normal `let` binding with optional type 268 /// A normal `let` binding with optional type annotation. The expression is expected to implement
269 /// [`PinInit`]/[`Init`] with the error type [ 269 /// [`PinInit`]/[`Init`] with the error type [`Infallible`]. If you want to use a different error
270 /// type, then use [`stack_try_pin_init!`]. 270 /// type, then use [`stack_try_pin_init!`].
271 /// 271 ///
272 /// [`stack_try_pin_init!`]: crate::stack_try_ 272 /// [`stack_try_pin_init!`]: crate::stack_try_pin_init!
273 #[macro_export] 273 #[macro_export]
274 macro_rules! stack_pin_init { 274 macro_rules! stack_pin_init {
275 (let $var:ident $(: $t:ty)? = $val:expr) = 275 (let $var:ident $(: $t:ty)? = $val:expr) => {
276 let val = $val; 276 let val = $val;
277 let mut $var = ::core::pin::pin!($crat 277 let mut $var = ::core::pin::pin!($crate::init::__internal::StackInit$(::<$t>)?::uninit());
278 let mut $var = match $crate::init::__i 278 let mut $var = match $crate::init::__internal::StackInit::init($var, val) {
279 Ok(res) => res, 279 Ok(res) => res,
280 Err(x) => { 280 Err(x) => {
281 let x: ::core::convert::Infall 281 let x: ::core::convert::Infallible = x;
282 match x {} 282 match x {}
283 } 283 }
284 }; 284 };
285 }; 285 };
286 } 286 }
287 287
288 /// Initialize and pin a type directly on the 288 /// Initialize and pin a type directly on the stack.
289 /// 289 ///
290 /// # Examples 290 /// # Examples
291 /// 291 ///
292 /// ```rust,ignore 292 /// ```rust,ignore
293 /// # #![allow(clippy::disallowed_names)] 293 /// # #![allow(clippy::disallowed_names)]
294 /// # use kernel::{init, pin_init, stack_try_p 294 /// # use kernel::{init, pin_init, stack_try_pin_init, init::*, sync::Mutex, new_mutex};
295 /// # use macros::pin_data; 295 /// # use macros::pin_data;
296 /// # use core::{alloc::AllocError, pin::Pin}; 296 /// # use core::{alloc::AllocError, pin::Pin};
297 /// #[pin_data] 297 /// #[pin_data]
298 /// struct Foo { 298 /// struct Foo {
299 /// #[pin] 299 /// #[pin]
300 /// a: Mutex<usize>, 300 /// a: Mutex<usize>,
301 /// b: Box<Bar>, 301 /// b: Box<Bar>,
302 /// } 302 /// }
303 /// 303 ///
304 /// struct Bar { 304 /// struct Bar {
305 /// x: u32, 305 /// x: u32,
306 /// } 306 /// }
307 /// 307 ///
308 /// stack_try_pin_init!(let foo: Result<Pin<&m 308 /// stack_try_pin_init!(let foo: Result<Pin<&mut Foo>, AllocError> = pin_init!(Foo {
309 /// a <- new_mutex!(42), 309 /// a <- new_mutex!(42),
310 /// b: Box::new(Bar { 310 /// b: Box::new(Bar {
311 /// x: 64, 311 /// x: 64,
312 /// }, GFP_KERNEL)?, 312 /// }, GFP_KERNEL)?,
313 /// })); 313 /// }));
314 /// let foo = foo.unwrap(); 314 /// let foo = foo.unwrap();
315 /// pr_info!("a: {}", &*foo.a.lock()); 315 /// pr_info!("a: {}", &*foo.a.lock());
316 /// ``` 316 /// ```
317 /// 317 ///
318 /// ```rust,ignore 318 /// ```rust,ignore
319 /// # #![allow(clippy::disallowed_names)] 319 /// # #![allow(clippy::disallowed_names)]
320 /// # use kernel::{init, pin_init, stack_try_p 320 /// # use kernel::{init, pin_init, stack_try_pin_init, init::*, sync::Mutex, new_mutex};
321 /// # use macros::pin_data; 321 /// # use macros::pin_data;
322 /// # use core::{alloc::AllocError, pin::Pin}; 322 /// # use core::{alloc::AllocError, pin::Pin};
323 /// #[pin_data] 323 /// #[pin_data]
324 /// struct Foo { 324 /// struct Foo {
325 /// #[pin] 325 /// #[pin]
326 /// a: Mutex<usize>, 326 /// a: Mutex<usize>,
327 /// b: Box<Bar>, 327 /// b: Box<Bar>,
328 /// } 328 /// }
329 /// 329 ///
330 /// struct Bar { 330 /// struct Bar {
331 /// x: u32, 331 /// x: u32,
332 /// } 332 /// }
333 /// 333 ///
334 /// stack_try_pin_init!(let foo: Pin<&mut Foo> 334 /// stack_try_pin_init!(let foo: Pin<&mut Foo> =? pin_init!(Foo {
335 /// a <- new_mutex!(42), 335 /// a <- new_mutex!(42),
336 /// b: Box::new(Bar { 336 /// b: Box::new(Bar {
337 /// x: 64, 337 /// x: 64,
338 /// }, GFP_KERNEL)?, 338 /// }, GFP_KERNEL)?,
339 /// })); 339 /// }));
340 /// pr_info!("a: {}", &*foo.a.lock()); 340 /// pr_info!("a: {}", &*foo.a.lock());
341 /// # Ok::<_, AllocError>(()) 341 /// # Ok::<_, AllocError>(())
342 /// ``` 342 /// ```
343 /// 343 ///
344 /// # Syntax 344 /// # Syntax
345 /// 345 ///
346 /// A normal `let` binding with optional type 346 /// A normal `let` binding with optional type annotation. The expression is expected to implement
347 /// [`PinInit`]/[`Init`]. This macro assigns a 347 /// [`PinInit`]/[`Init`]. This macro assigns a result to the given variable, adding a `?` after the
348 /// `=` will propagate this error. 348 /// `=` will propagate this error.
349 #[macro_export] 349 #[macro_export]
350 macro_rules! stack_try_pin_init { 350 macro_rules! stack_try_pin_init {
351 (let $var:ident $(: $t:ty)? = $val:expr) = 351 (let $var:ident $(: $t:ty)? = $val:expr) => {
352 let val = $val; 352 let val = $val;
353 let mut $var = ::core::pin::pin!($crat 353 let mut $var = ::core::pin::pin!($crate::init::__internal::StackInit$(::<$t>)?::uninit());
354 let mut $var = $crate::init::__interna 354 let mut $var = $crate::init::__internal::StackInit::init($var, val);
355 }; 355 };
356 (let $var:ident $(: $t:ty)? =? $val:expr) 356 (let $var:ident $(: $t:ty)? =? $val:expr) => {
357 let val = $val; 357 let val = $val;
358 let mut $var = ::core::pin::pin!($crat 358 let mut $var = ::core::pin::pin!($crate::init::__internal::StackInit$(::<$t>)?::uninit());
359 let mut $var = $crate::init::__interna 359 let mut $var = $crate::init::__internal::StackInit::init($var, val)?;
360 }; 360 };
361 } 361 }
362 362
363 /// Construct an in-place, pinned initializer 363 /// Construct an in-place, pinned initializer for `struct`s.
364 /// 364 ///
365 /// This macro defaults the error to [`Infalli 365 /// This macro defaults the error to [`Infallible`]. If you need [`Error`], then use
366 /// [`try_pin_init!`]. 366 /// [`try_pin_init!`].
367 /// 367 ///
368 /// The syntax is almost identical to that of 368 /// The syntax is almost identical to that of a normal `struct` initializer:
369 /// 369 ///
370 /// ```rust 370 /// ```rust
371 /// # #![allow(clippy::disallowed_names)] 371 /// # #![allow(clippy::disallowed_names)]
372 /// # use kernel::{init, pin_init, macros::pin 372 /// # use kernel::{init, pin_init, macros::pin_data, init::*};
373 /// # use core::pin::Pin; 373 /// # use core::pin::Pin;
374 /// #[pin_data] 374 /// #[pin_data]
375 /// struct Foo { 375 /// struct Foo {
376 /// a: usize, 376 /// a: usize,
377 /// b: Bar, 377 /// b: Bar,
378 /// } 378 /// }
379 /// 379 ///
380 /// #[pin_data] 380 /// #[pin_data]
381 /// struct Bar { 381 /// struct Bar {
382 /// x: u32, 382 /// x: u32,
383 /// } 383 /// }
384 /// 384 ///
385 /// # fn demo() -> impl PinInit<Foo> { 385 /// # fn demo() -> impl PinInit<Foo> {
386 /// let a = 42; 386 /// let a = 42;
387 /// 387 ///
388 /// let initializer = pin_init!(Foo { 388 /// let initializer = pin_init!(Foo {
389 /// a, 389 /// a,
390 /// b: Bar { 390 /// b: Bar {
391 /// x: 64, 391 /// x: 64,
392 /// }, 392 /// },
393 /// }); 393 /// });
394 /// # initializer } 394 /// # initializer }
395 /// # Box::pin_init(demo(), GFP_KERNEL).unwrap 395 /// # Box::pin_init(demo(), GFP_KERNEL).unwrap();
396 /// ``` 396 /// ```
397 /// 397 ///
398 /// Arbitrary Rust expressions can be used to 398 /// Arbitrary Rust expressions can be used to set the value of a variable.
399 /// 399 ///
400 /// The fields are initialized in the order th 400 /// The fields are initialized in the order that they appear in the initializer. So it is possible
401 /// to read already initialized fields using r 401 /// to read already initialized fields using raw pointers.
402 /// 402 ///
403 /// IMPORTANT: You are not allowed to create r 403 /// IMPORTANT: You are not allowed to create references to fields of the struct inside of the
404 /// initializer. 404 /// initializer.
405 /// 405 ///
406 /// # Init-functions 406 /// # Init-functions
407 /// 407 ///
408 /// When working with this API it is often des 408 /// When working with this API it is often desired to let others construct your types without
409 /// giving access to all fields. This is where 409 /// giving access to all fields. This is where you would normally write a plain function `new`
410 /// that would return a new instance of your t 410 /// that would return a new instance of your type. With this API that is also possible.
411 /// However, there are a few extra things to k 411 /// However, there are a few extra things to keep in mind.
412 /// 412 ///
413 /// To create an initializer function, simply 413 /// To create an initializer function, simply declare it like this:
414 /// 414 ///
415 /// ```rust 415 /// ```rust
416 /// # #![allow(clippy::disallowed_names)] 416 /// # #![allow(clippy::disallowed_names)]
417 /// # use kernel::{init, pin_init, init::*}; 417 /// # use kernel::{init, pin_init, init::*};
418 /// # use core::pin::Pin; 418 /// # use core::pin::Pin;
419 /// # #[pin_data] 419 /// # #[pin_data]
420 /// # struct Foo { 420 /// # struct Foo {
421 /// # a: usize, 421 /// # a: usize,
422 /// # b: Bar, 422 /// # b: Bar,
423 /// # } 423 /// # }
424 /// # #[pin_data] 424 /// # #[pin_data]
425 /// # struct Bar { 425 /// # struct Bar {
426 /// # x: u32, 426 /// # x: u32,
427 /// # } 427 /// # }
428 /// impl Foo { 428 /// impl Foo {
429 /// fn new() -> impl PinInit<Self> { 429 /// fn new() -> impl PinInit<Self> {
430 /// pin_init!(Self { 430 /// pin_init!(Self {
431 /// a: 42, 431 /// a: 42,
432 /// b: Bar { 432 /// b: Bar {
433 /// x: 64, 433 /// x: 64,
434 /// }, 434 /// },
435 /// }) 435 /// })
436 /// } 436 /// }
437 /// } 437 /// }
438 /// ``` 438 /// ```
439 /// 439 ///
440 /// Users of `Foo` can now create it like this 440 /// Users of `Foo` can now create it like this:
441 /// 441 ///
442 /// ```rust 442 /// ```rust
443 /// # #![allow(clippy::disallowed_names)] 443 /// # #![allow(clippy::disallowed_names)]
444 /// # use kernel::{init, pin_init, macros::pin 444 /// # use kernel::{init, pin_init, macros::pin_data, init::*};
445 /// # use core::pin::Pin; 445 /// # use core::pin::Pin;
446 /// # #[pin_data] 446 /// # #[pin_data]
447 /// # struct Foo { 447 /// # struct Foo {
448 /// # a: usize, 448 /// # a: usize,
449 /// # b: Bar, 449 /// # b: Bar,
450 /// # } 450 /// # }
451 /// # #[pin_data] 451 /// # #[pin_data]
452 /// # struct Bar { 452 /// # struct Bar {
453 /// # x: u32, 453 /// # x: u32,
454 /// # } 454 /// # }
455 /// # impl Foo { 455 /// # impl Foo {
456 /// # fn new() -> impl PinInit<Self> { 456 /// # fn new() -> impl PinInit<Self> {
457 /// # pin_init!(Self { 457 /// # pin_init!(Self {
458 /// # a: 42, 458 /// # a: 42,
459 /// # b: Bar { 459 /// # b: Bar {
460 /// # x: 64, 460 /// # x: 64,
461 /// # }, 461 /// # },
462 /// # }) 462 /// # })
463 /// # } 463 /// # }
464 /// # } 464 /// # }
465 /// let foo = Box::pin_init(Foo::new(), GFP_KE 465 /// let foo = Box::pin_init(Foo::new(), GFP_KERNEL);
466 /// ``` 466 /// ```
467 /// 467 ///
468 /// They can also easily embed it into their o 468 /// They can also easily embed it into their own `struct`s:
469 /// 469 ///
470 /// ```rust 470 /// ```rust
471 /// # #![allow(clippy::disallowed_names)] 471 /// # #![allow(clippy::disallowed_names)]
472 /// # use kernel::{init, pin_init, macros::pin 472 /// # use kernel::{init, pin_init, macros::pin_data, init::*};
473 /// # use core::pin::Pin; 473 /// # use core::pin::Pin;
474 /// # #[pin_data] 474 /// # #[pin_data]
475 /// # struct Foo { 475 /// # struct Foo {
476 /// # a: usize, 476 /// # a: usize,
477 /// # b: Bar, 477 /// # b: Bar,
478 /// # } 478 /// # }
479 /// # #[pin_data] 479 /// # #[pin_data]
480 /// # struct Bar { 480 /// # struct Bar {
481 /// # x: u32, 481 /// # x: u32,
482 /// # } 482 /// # }
483 /// # impl Foo { 483 /// # impl Foo {
484 /// # fn new() -> impl PinInit<Self> { 484 /// # fn new() -> impl PinInit<Self> {
485 /// # pin_init!(Self { 485 /// # pin_init!(Self {
486 /// # a: 42, 486 /// # a: 42,
487 /// # b: Bar { 487 /// # b: Bar {
488 /// # x: 64, 488 /// # x: 64,
489 /// # }, 489 /// # },
490 /// # }) 490 /// # })
491 /// # } 491 /// # }
492 /// # } 492 /// # }
493 /// #[pin_data] 493 /// #[pin_data]
494 /// struct FooContainer { 494 /// struct FooContainer {
495 /// #[pin] 495 /// #[pin]
496 /// foo1: Foo, 496 /// foo1: Foo,
497 /// #[pin] 497 /// #[pin]
498 /// foo2: Foo, 498 /// foo2: Foo,
499 /// other: u32, 499 /// other: u32,
500 /// } 500 /// }
501 /// 501 ///
502 /// impl FooContainer { 502 /// impl FooContainer {
503 /// fn new(other: u32) -> impl PinInit<Sel 503 /// fn new(other: u32) -> impl PinInit<Self> {
504 /// pin_init!(Self { 504 /// pin_init!(Self {
505 /// foo1 <- Foo::new(), 505 /// foo1 <- Foo::new(),
506 /// foo2 <- Foo::new(), 506 /// foo2 <- Foo::new(),
507 /// other, 507 /// other,
508 /// }) 508 /// })
509 /// } 509 /// }
510 /// } 510 /// }
511 /// ``` 511 /// ```
512 /// 512 ///
513 /// Here we see that when using `pin_init!` wi 513 /// Here we see that when using `pin_init!` with `PinInit`, one needs to write `<-` instead of `:`.
514 /// This signifies that the given field is ini 514 /// This signifies that the given field is initialized in-place. As with `struct` initializers, just
515 /// writing the field (in this case `other`) w 515 /// writing the field (in this case `other`) without `:` or `<-` means `other: other,`.
516 /// 516 ///
517 /// # Syntax 517 /// # Syntax
518 /// 518 ///
519 /// As already mentioned in the examples above 519 /// As already mentioned in the examples above, inside of `pin_init!` a `struct` initializer with
520 /// the following modifications is expected: 520 /// the following modifications is expected:
521 /// - Fields that you want to initialize in-pl 521 /// - Fields that you want to initialize in-place have to use `<-` instead of `:`.
522 /// - In front of the initializer you can writ 522 /// - In front of the initializer you can write `&this in` to have access to a [`NonNull<Self>`]
523 /// pointer named `this` inside of the initi 523 /// pointer named `this` inside of the initializer.
524 /// - Using struct update syntax one can place 524 /// - Using struct update syntax one can place `..Zeroable::zeroed()` at the very end of the
525 /// struct, this initializes every field wit 525 /// struct, this initializes every field with 0 and then runs all initializers specified in the
526 /// body. This can only be done if [`Zeroabl 526 /// body. This can only be done if [`Zeroable`] is implemented for the struct.
527 /// 527 ///
528 /// For instance: 528 /// For instance:
529 /// 529 ///
530 /// ```rust 530 /// ```rust
531 /// # use kernel::{macros::{Zeroable, pin_data 531 /// # use kernel::{macros::{Zeroable, pin_data}, pin_init};
532 /// # use core::{ptr::addr_of_mut, marker::Pha 532 /// # use core::{ptr::addr_of_mut, marker::PhantomPinned};
533 /// #[pin_data] 533 /// #[pin_data]
534 /// #[derive(Zeroable)] 534 /// #[derive(Zeroable)]
535 /// struct Buf { 535 /// struct Buf {
536 /// // `ptr` points into `buf`. 536 /// // `ptr` points into `buf`.
537 /// ptr: *mut u8, 537 /// ptr: *mut u8,
538 /// buf: [u8; 64], 538 /// buf: [u8; 64],
539 /// #[pin] 539 /// #[pin]
540 /// pin: PhantomPinned, 540 /// pin: PhantomPinned,
541 /// } 541 /// }
542 /// pin_init!(&this in Buf { 542 /// pin_init!(&this in Buf {
543 /// buf: [0; 64], 543 /// buf: [0; 64],
544 /// ptr: unsafe { addr_of_mut!((*this.as_p 544 /// ptr: unsafe { addr_of_mut!((*this.as_ptr()).buf).cast() },
545 /// pin: PhantomPinned, 545 /// pin: PhantomPinned,
546 /// }); 546 /// });
547 /// pin_init!(Buf { 547 /// pin_init!(Buf {
548 /// buf: [1; 64], 548 /// buf: [1; 64],
549 /// ..Zeroable::zeroed() 549 /// ..Zeroable::zeroed()
550 /// }); 550 /// });
551 /// ``` 551 /// ```
552 /// 552 ///
553 /// [`try_pin_init!`]: kernel::try_pin_init 553 /// [`try_pin_init!`]: kernel::try_pin_init
554 /// [`NonNull<Self>`]: core::ptr::NonNull 554 /// [`NonNull<Self>`]: core::ptr::NonNull
555 // For a detailed example of how this macro wo 555 // For a detailed example of how this macro works, see the module documentation of the hidden
556 // module `__internal` inside of `init/__inter 556 // module `__internal` inside of `init/__internal.rs`.
557 #[macro_export] 557 #[macro_export]
558 macro_rules! pin_init { 558 macro_rules! pin_init {
559 ($(&$this:ident in)? $t:ident $(::<$($gene 559 ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? {
560 $($fields:tt)* 560 $($fields:tt)*
561 }) => { 561 }) => {
562 $crate::__init_internal!( 562 $crate::__init_internal!(
563 @this($($this)?), 563 @this($($this)?),
564 @typ($t $(::<$($generics),*>)?), 564 @typ($t $(::<$($generics),*>)?),
565 @fields($($fields)*), 565 @fields($($fields)*),
566 @error(::core::convert::Infallible 566 @error(::core::convert::Infallible),
567 @data(PinData, use_data), 567 @data(PinData, use_data),
568 @has_data(HasPinData, __pin_data), 568 @has_data(HasPinData, __pin_data),
569 @construct_closure(pin_init_from_c 569 @construct_closure(pin_init_from_closure),
570 @munch_fields($($fields)*), 570 @munch_fields($($fields)*),
571 ) 571 )
572 }; 572 };
573 } 573 }
574 574
575 /// Construct an in-place, fallible pinned ini 575 /// Construct an in-place, fallible pinned initializer for `struct`s.
576 /// 576 ///
577 /// If the initialization can complete without 577 /// If the initialization can complete without error (or [`Infallible`]), then use [`pin_init!`].
578 /// 578 ///
579 /// You can use the `?` operator or use `retur 579 /// You can use the `?` operator or use `return Err(err)` inside the initializer to stop
580 /// initialization and return the error. 580 /// initialization and return the error.
581 /// 581 ///
582 /// IMPORTANT: if you have `unsafe` code insid 582 /// IMPORTANT: if you have `unsafe` code inside of the initializer you have to ensure that when
583 /// initialization fails, the memory can be sa 583 /// initialization fails, the memory can be safely deallocated without any further modifications.
584 /// 584 ///
585 /// This macro defaults the error to [`Error`] 585 /// This macro defaults the error to [`Error`].
586 /// 586 ///
587 /// The syntax is identical to [`pin_init!`] w 587 /// The syntax is identical to [`pin_init!`] with the following exception: you can append `? $type`
588 /// after the `struct` initializer to specify 588 /// after the `struct` initializer to specify the error type you want to use.
589 /// 589 ///
590 /// # Examples 590 /// # Examples
591 /// 591 ///
592 /// ```rust 592 /// ```rust
593 /// # #![feature(new_uninit)] 593 /// # #![feature(new_uninit)]
594 /// use kernel::{init::{self, PinInit}, error: 594 /// use kernel::{init::{self, PinInit}, error::Error};
595 /// #[pin_data] 595 /// #[pin_data]
596 /// struct BigBuf { 596 /// struct BigBuf {
597 /// big: Box<[u8; 1024 * 1024 * 1024]>, 597 /// big: Box<[u8; 1024 * 1024 * 1024]>,
598 /// small: [u8; 1024 * 1024], 598 /// small: [u8; 1024 * 1024],
599 /// ptr: *mut u8, 599 /// ptr: *mut u8,
600 /// } 600 /// }
601 /// 601 ///
602 /// impl BigBuf { 602 /// impl BigBuf {
603 /// fn new() -> impl PinInit<Self, Error> 603 /// fn new() -> impl PinInit<Self, Error> {
604 /// try_pin_init!(Self { 604 /// try_pin_init!(Self {
605 /// big: Box::init(init::zeroed(), 605 /// big: Box::init(init::zeroed(), GFP_KERNEL)?,
606 /// small: [0; 1024 * 1024], 606 /// small: [0; 1024 * 1024],
607 /// ptr: core::ptr::null_mut(), 607 /// ptr: core::ptr::null_mut(),
608 /// }? Error) 608 /// }? Error)
609 /// } 609 /// }
610 /// } 610 /// }
611 /// ``` 611 /// ```
612 // For a detailed example of how this macro wo 612 // For a detailed example of how this macro works, see the module documentation of the hidden
613 // module `__internal` inside of `init/__inter 613 // module `__internal` inside of `init/__internal.rs`.
614 #[macro_export] 614 #[macro_export]
615 macro_rules! try_pin_init { 615 macro_rules! try_pin_init {
616 ($(&$this:ident in)? $t:ident $(::<$($gene 616 ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? {
617 $($fields:tt)* 617 $($fields:tt)*
618 }) => { 618 }) => {
619 $crate::__init_internal!( 619 $crate::__init_internal!(
620 @this($($this)?), 620 @this($($this)?),
621 @typ($t $(::<$($generics),*>)? ), 621 @typ($t $(::<$($generics),*>)? ),
622 @fields($($fields)*), 622 @fields($($fields)*),
623 @error($crate::error::Error), 623 @error($crate::error::Error),
624 @data(PinData, use_data), 624 @data(PinData, use_data),
625 @has_data(HasPinData, __pin_data), 625 @has_data(HasPinData, __pin_data),
626 @construct_closure(pin_init_from_c 626 @construct_closure(pin_init_from_closure),
627 @munch_fields($($fields)*), 627 @munch_fields($($fields)*),
628 ) 628 )
629 }; 629 };
630 ($(&$this:ident in)? $t:ident $(::<$($gene 630 ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? {
631 $($fields:tt)* 631 $($fields:tt)*
632 }? $err:ty) => { 632 }? $err:ty) => {
633 $crate::__init_internal!( 633 $crate::__init_internal!(
634 @this($($this)?), 634 @this($($this)?),
635 @typ($t $(::<$($generics),*>)? ), 635 @typ($t $(::<$($generics),*>)? ),
636 @fields($($fields)*), 636 @fields($($fields)*),
637 @error($err), 637 @error($err),
638 @data(PinData, use_data), 638 @data(PinData, use_data),
639 @has_data(HasPinData, __pin_data), 639 @has_data(HasPinData, __pin_data),
640 @construct_closure(pin_init_from_c 640 @construct_closure(pin_init_from_closure),
641 @munch_fields($($fields)*), 641 @munch_fields($($fields)*),
642 ) 642 )
643 }; 643 };
644 } 644 }
645 645
646 /// Construct an in-place initializer for `str 646 /// Construct an in-place initializer for `struct`s.
647 /// 647 ///
648 /// This macro defaults the error to [`Infalli 648 /// This macro defaults the error to [`Infallible`]. If you need [`Error`], then use
649 /// [`try_init!`]. 649 /// [`try_init!`].
650 /// 650 ///
651 /// The syntax is identical to [`pin_init!`] a 651 /// The syntax is identical to [`pin_init!`] and its safety caveats also apply:
652 /// - `unsafe` code must guarantee either full 652 /// - `unsafe` code must guarantee either full initialization or return an error and allow
653 /// deallocation of the memory. 653 /// deallocation of the memory.
654 /// - the fields are initialized in the order 654 /// - the fields are initialized in the order given in the initializer.
655 /// - no references to fields are allowed to b 655 /// - no references to fields are allowed to be created inside of the initializer.
656 /// 656 ///
657 /// This initializer is for initializing data 657 /// This initializer is for initializing data in-place that might later be moved. If you want to
658 /// pin-initialize, use [`pin_init!`]. 658 /// pin-initialize, use [`pin_init!`].
659 /// 659 ///
660 /// [`try_init!`]: crate::try_init! 660 /// [`try_init!`]: crate::try_init!
661 // For a detailed example of how this macro wo 661 // For a detailed example of how this macro works, see the module documentation of the hidden
662 // module `__internal` inside of `init/__inter 662 // module `__internal` inside of `init/__internal.rs`.
663 #[macro_export] 663 #[macro_export]
664 macro_rules! init { 664 macro_rules! init {
665 ($(&$this:ident in)? $t:ident $(::<$($gene 665 ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? {
666 $($fields:tt)* 666 $($fields:tt)*
667 }) => { 667 }) => {
668 $crate::__init_internal!( 668 $crate::__init_internal!(
669 @this($($this)?), 669 @this($($this)?),
670 @typ($t $(::<$($generics),*>)?), 670 @typ($t $(::<$($generics),*>)?),
671 @fields($($fields)*), 671 @fields($($fields)*),
672 @error(::core::convert::Infallible 672 @error(::core::convert::Infallible),
673 @data(InitData, /*no use_data*/), 673 @data(InitData, /*no use_data*/),
674 @has_data(HasInitData, __init_data 674 @has_data(HasInitData, __init_data),
675 @construct_closure(init_from_closu 675 @construct_closure(init_from_closure),
676 @munch_fields($($fields)*), 676 @munch_fields($($fields)*),
677 ) 677 )
678 } 678 }
679 } 679 }
680 680
681 /// Construct an in-place fallible initializer 681 /// Construct an in-place fallible initializer for `struct`s.
682 /// 682 ///
683 /// This macro defaults the error to [`Error`] 683 /// This macro defaults the error to [`Error`]. If you need [`Infallible`], then use
684 /// [`init!`]. 684 /// [`init!`].
685 /// 685 ///
686 /// The syntax is identical to [`try_pin_init! 686 /// The syntax is identical to [`try_pin_init!`]. If you want to specify a custom error,
687 /// append `? $type` after the `struct` initia 687 /// append `? $type` after the `struct` initializer.
688 /// The safety caveats from [`try_pin_init!`] 688 /// The safety caveats from [`try_pin_init!`] also apply:
689 /// - `unsafe` code must guarantee either full 689 /// - `unsafe` code must guarantee either full initialization or return an error and allow
690 /// deallocation of the memory. 690 /// deallocation of the memory.
691 /// - the fields are initialized in the order 691 /// - the fields are initialized in the order given in the initializer.
692 /// - no references to fields are allowed to b 692 /// - no references to fields are allowed to be created inside of the initializer.
693 /// 693 ///
694 /// # Examples 694 /// # Examples
695 /// 695 ///
696 /// ```rust 696 /// ```rust
697 /// use kernel::{init::{PinInit, zeroed}, erro 697 /// use kernel::{init::{PinInit, zeroed}, error::Error};
698 /// struct BigBuf { 698 /// struct BigBuf {
699 /// big: Box<[u8; 1024 * 1024 * 1024]>, 699 /// big: Box<[u8; 1024 * 1024 * 1024]>,
700 /// small: [u8; 1024 * 1024], 700 /// small: [u8; 1024 * 1024],
701 /// } 701 /// }
702 /// 702 ///
703 /// impl BigBuf { 703 /// impl BigBuf {
704 /// fn new() -> impl Init<Self, Error> { 704 /// fn new() -> impl Init<Self, Error> {
705 /// try_init!(Self { 705 /// try_init!(Self {
706 /// big: Box::init(zeroed(), GFP_K 706 /// big: Box::init(zeroed(), GFP_KERNEL)?,
707 /// small: [0; 1024 * 1024], 707 /// small: [0; 1024 * 1024],
708 /// }? Error) 708 /// }? Error)
709 /// } 709 /// }
710 /// } 710 /// }
711 /// ``` 711 /// ```
712 // For a detailed example of how this macro wo 712 // For a detailed example of how this macro works, see the module documentation of the hidden
713 // module `__internal` inside of `init/__inter 713 // module `__internal` inside of `init/__internal.rs`.
714 #[macro_export] 714 #[macro_export]
715 macro_rules! try_init { 715 macro_rules! try_init {
716 ($(&$this:ident in)? $t:ident $(::<$($gene 716 ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? {
717 $($fields:tt)* 717 $($fields:tt)*
718 }) => { 718 }) => {
719 $crate::__init_internal!( 719 $crate::__init_internal!(
720 @this($($this)?), 720 @this($($this)?),
721 @typ($t $(::<$($generics),*>)?), 721 @typ($t $(::<$($generics),*>)?),
722 @fields($($fields)*), 722 @fields($($fields)*),
723 @error($crate::error::Error), 723 @error($crate::error::Error),
724 @data(InitData, /*no use_data*/), 724 @data(InitData, /*no use_data*/),
725 @has_data(HasInitData, __init_data 725 @has_data(HasInitData, __init_data),
726 @construct_closure(init_from_closu 726 @construct_closure(init_from_closure),
727 @munch_fields($($fields)*), 727 @munch_fields($($fields)*),
728 ) 728 )
729 }; 729 };
730 ($(&$this:ident in)? $t:ident $(::<$($gene 730 ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? {
731 $($fields:tt)* 731 $($fields:tt)*
732 }? $err:ty) => { 732 }? $err:ty) => {
733 $crate::__init_internal!( 733 $crate::__init_internal!(
734 @this($($this)?), 734 @this($($this)?),
735 @typ($t $(::<$($generics),*>)?), 735 @typ($t $(::<$($generics),*>)?),
736 @fields($($fields)*), 736 @fields($($fields)*),
737 @error($err), 737 @error($err),
738 @data(InitData, /*no use_data*/), 738 @data(InitData, /*no use_data*/),
739 @has_data(HasInitData, __init_data 739 @has_data(HasInitData, __init_data),
740 @construct_closure(init_from_closu 740 @construct_closure(init_from_closure),
741 @munch_fields($($fields)*), 741 @munch_fields($($fields)*),
742 ) 742 )
743 }; 743 };
744 } 744 }
745 745
746 /// Asserts that a field on a struct using `#[ 746 /// Asserts that a field on a struct using `#[pin_data]` is marked with `#[pin]` ie. that it is
747 /// structurally pinned. 747 /// structurally pinned.
748 /// 748 ///
749 /// # Example 749 /// # Example
750 /// 750 ///
751 /// This will succeed: 751 /// This will succeed:
752 /// ``` 752 /// ```
753 /// use kernel::assert_pinned; 753 /// use kernel::assert_pinned;
754 /// #[pin_data] 754 /// #[pin_data]
755 /// struct MyStruct { 755 /// struct MyStruct {
756 /// #[pin] 756 /// #[pin]
757 /// some_field: u64, 757 /// some_field: u64,
758 /// } 758 /// }
759 /// 759 ///
760 /// assert_pinned!(MyStruct, some_field, u64); 760 /// assert_pinned!(MyStruct, some_field, u64);
761 /// ``` 761 /// ```
762 /// 762 ///
763 /// This will fail: 763 /// This will fail:
764 // TODO: replace with `compile_fail` when supp 764 // TODO: replace with `compile_fail` when supported.
765 /// ```ignore 765 /// ```ignore
766 /// use kernel::assert_pinned; 766 /// use kernel::assert_pinned;
767 /// #[pin_data] 767 /// #[pin_data]
768 /// struct MyStruct { 768 /// struct MyStruct {
769 /// some_field: u64, 769 /// some_field: u64,
770 /// } 770 /// }
771 /// 771 ///
772 /// assert_pinned!(MyStruct, some_field, u64); 772 /// assert_pinned!(MyStruct, some_field, u64);
773 /// ``` 773 /// ```
774 /// 774 ///
775 /// Some uses of the macro may trigger the `ca 775 /// Some uses of the macro may trigger the `can't use generic parameters from outer item` error. To
776 /// work around this, you may pass the `inline 776 /// work around this, you may pass the `inline` parameter to the macro. The `inline` parameter can
777 /// only be used when the macro is invoked fro 777 /// only be used when the macro is invoked from a function body.
778 /// ``` 778 /// ```
779 /// use kernel::assert_pinned; 779 /// use kernel::assert_pinned;
780 /// #[pin_data] 780 /// #[pin_data]
781 /// struct Foo<T> { 781 /// struct Foo<T> {
782 /// #[pin] 782 /// #[pin]
783 /// elem: T, 783 /// elem: T,
784 /// } 784 /// }
785 /// 785 ///
786 /// impl<T> Foo<T> { 786 /// impl<T> Foo<T> {
787 /// fn project(self: Pin<&mut Self>) -> Pi 787 /// fn project(self: Pin<&mut Self>) -> Pin<&mut T> {
788 /// assert_pinned!(Foo<T>, elem, T, in 788 /// assert_pinned!(Foo<T>, elem, T, inline);
789 /// 789 ///
790 /// // SAFETY: The field is structural 790 /// // SAFETY: The field is structurally pinned.
791 /// unsafe { self.map_unchecked_mut(|m 791 /// unsafe { self.map_unchecked_mut(|me| &mut me.elem) }
792 /// } 792 /// }
793 /// } 793 /// }
794 /// ``` 794 /// ```
795 #[macro_export] 795 #[macro_export]
796 macro_rules! assert_pinned { 796 macro_rules! assert_pinned {
797 ($ty:ty, $field:ident, $field_ty:ty, inlin 797 ($ty:ty, $field:ident, $field_ty:ty, inline) => {
798 let _ = move |ptr: *mut $field_ty| { 798 let _ = move |ptr: *mut $field_ty| {
799 // SAFETY: This code is unreachabl 799 // SAFETY: This code is unreachable.
800 let data = unsafe { <$ty as $crate 800 let data = unsafe { <$ty as $crate::init::__internal::HasPinData>::__pin_data() };
801 let init = $crate::init::__interna 801 let init = $crate::init::__internal::AlwaysFail::<$field_ty>::new();
802 // SAFETY: This code is unreachabl 802 // SAFETY: This code is unreachable.
803 unsafe { data.$field(ptr, init) }. 803 unsafe { data.$field(ptr, init) }.ok();
804 }; 804 };
805 }; 805 };
806 806
807 ($ty:ty, $field:ident, $field_ty:ty) => { 807 ($ty:ty, $field:ident, $field_ty:ty) => {
808 const _: () = { 808 const _: () = {
809 $crate::assert_pinned!($ty, $field 809 $crate::assert_pinned!($ty, $field, $field_ty, inline);
810 }; 810 };
811 }; 811 };
812 } 812 }
813 813
814 /// A pin-initializer for the type `T`. 814 /// A pin-initializer for the type `T`.
815 /// 815 ///
816 /// To use this initializer, you will need a s 816 /// To use this initializer, you will need a suitable memory location that can hold a `T`. This can
817 /// be [`Box<T>`], [`Arc<T>`], [`UniqueArc<T>` 817 /// be [`Box<T>`], [`Arc<T>`], [`UniqueArc<T>`] or even the stack (see [`stack_pin_init!`]). Use the
818 /// [`InPlaceInit::pin_init`] function of a sm 818 /// [`InPlaceInit::pin_init`] function of a smart pointer like [`Arc<T>`] on this.
819 /// 819 ///
820 /// Also see the [module description](self). 820 /// Also see the [module description](self).
821 /// 821 ///
822 /// # Safety 822 /// # Safety
823 /// 823 ///
824 /// When implementing this trait you will need 824 /// When implementing this trait you will need to take great care. Also there are probably very few
825 /// cases where a manual implementation is nec 825 /// cases where a manual implementation is necessary. Use [`pin_init_from_closure`] where possible.
826 /// 826 ///
827 /// The [`PinInit::__pinned_init`] function: 827 /// The [`PinInit::__pinned_init`] function:
828 /// - returns `Ok(())` if it initialized every 828 /// - returns `Ok(())` if it initialized every field of `slot`,
829 /// - returns `Err(err)` if it encountered an 829 /// - returns `Err(err)` if it encountered an error and then cleaned `slot`, this means:
830 /// - `slot` can be deallocated without UB 830 /// - `slot` can be deallocated without UB occurring,
831 /// - `slot` does not need to be dropped, 831 /// - `slot` does not need to be dropped,
832 /// - `slot` is not partially initialized. 832 /// - `slot` is not partially initialized.
833 /// - while constructing the `T` at `slot` it 833 /// - while constructing the `T` at `slot` it upholds the pinning invariants of `T`.
834 /// 834 ///
835 /// [`Arc<T>`]: crate::sync::Arc 835 /// [`Arc<T>`]: crate::sync::Arc
836 /// [`Arc::pin_init`]: crate::sync::Arc::pin_i 836 /// [`Arc::pin_init`]: crate::sync::Arc::pin_init
837 #[must_use = "An initializer must be used in o 837 #[must_use = "An initializer must be used in order to create its value."]
838 pub unsafe trait PinInit<T: ?Sized, E = Infall 838 pub unsafe trait PinInit<T: ?Sized, E = Infallible>: Sized {
839 /// Initializes `slot`. 839 /// Initializes `slot`.
840 /// 840 ///
841 /// # Safety 841 /// # Safety
842 /// 842 ///
843 /// - `slot` is a valid pointer to uniniti 843 /// - `slot` is a valid pointer to uninitialized memory.
844 /// - the caller does not touch `slot` whe 844 /// - the caller does not touch `slot` when `Err` is returned, they are only permitted to
845 /// deallocate. 845 /// deallocate.
846 /// - `slot` will not move until it is dro 846 /// - `slot` will not move until it is dropped, i.e. it will be pinned.
847 unsafe fn __pinned_init(self, slot: *mut T 847 unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E>;
848 848
849 /// First initializes the value using `sel 849 /// First initializes the value using `self` then calls the function `f` with the initialized
850 /// value. 850 /// value.
851 /// 851 ///
852 /// If `f` returns an error the value is d 852 /// If `f` returns an error the value is dropped and the initializer will forward the error.
853 /// 853 ///
854 /// # Examples 854 /// # Examples
855 /// 855 ///
856 /// ```rust 856 /// ```rust
857 /// # #![allow(clippy::disallowed_names)] 857 /// # #![allow(clippy::disallowed_names)]
858 /// use kernel::{types::Opaque, init::pin_ 858 /// use kernel::{types::Opaque, init::pin_init_from_closure};
859 /// #[repr(C)] 859 /// #[repr(C)]
860 /// struct RawFoo([u8; 16]); 860 /// struct RawFoo([u8; 16]);
861 /// extern { 861 /// extern {
862 /// fn init_foo(_: *mut RawFoo); 862 /// fn init_foo(_: *mut RawFoo);
863 /// } 863 /// }
864 /// 864 ///
865 /// #[pin_data] 865 /// #[pin_data]
866 /// struct Foo { 866 /// struct Foo {
867 /// #[pin] 867 /// #[pin]
868 /// raw: Opaque<RawFoo>, 868 /// raw: Opaque<RawFoo>,
869 /// } 869 /// }
870 /// 870 ///
871 /// impl Foo { 871 /// impl Foo {
872 /// fn setup(self: Pin<&mut Self>) { 872 /// fn setup(self: Pin<&mut Self>) {
873 /// pr_info!("Setting up foo"); 873 /// pr_info!("Setting up foo");
874 /// } 874 /// }
875 /// } 875 /// }
876 /// 876 ///
877 /// let foo = pin_init!(Foo { 877 /// let foo = pin_init!(Foo {
878 /// raw <- unsafe { 878 /// raw <- unsafe {
879 /// Opaque::ffi_init(|s| { 879 /// Opaque::ffi_init(|s| {
880 /// init_foo(s); 880 /// init_foo(s);
881 /// }) 881 /// })
882 /// }, 882 /// },
883 /// }).pin_chain(|foo| { 883 /// }).pin_chain(|foo| {
884 /// foo.setup(); 884 /// foo.setup();
885 /// Ok(()) 885 /// Ok(())
886 /// }); 886 /// });
887 /// ``` 887 /// ```
888 fn pin_chain<F>(self, f: F) -> ChainPinIni 888 fn pin_chain<F>(self, f: F) -> ChainPinInit<Self, F, T, E>
889 where 889 where
890 F: FnOnce(Pin<&mut T>) -> Result<(), E 890 F: FnOnce(Pin<&mut T>) -> Result<(), E>,
891 { 891 {
892 ChainPinInit(self, f, PhantomData) 892 ChainPinInit(self, f, PhantomData)
893 } 893 }
894 } 894 }
895 895
896 /// An initializer returned by [`PinInit::pin_ 896 /// An initializer returned by [`PinInit::pin_chain`].
897 pub struct ChainPinInit<I, F, T: ?Sized, E>(I, 897 pub struct ChainPinInit<I, F, T: ?Sized, E>(I, F, __internal::Invariant<(E, Box<T>)>);
898 898
899 // SAFETY: The `__pinned_init` function is imp 899 // SAFETY: The `__pinned_init` function is implemented such that it
900 // - returns `Ok(())` on successful initializa 900 // - returns `Ok(())` on successful initialization,
901 // - returns `Err(err)` on error and in this c 901 // - returns `Err(err)` on error and in this case `slot` will be dropped.
902 // - considers `slot` pinned. 902 // - considers `slot` pinned.
903 unsafe impl<T: ?Sized, E, I, F> PinInit<T, E> 903 unsafe impl<T: ?Sized, E, I, F> PinInit<T, E> for ChainPinInit<I, F, T, E>
904 where 904 where
905 I: PinInit<T, E>, 905 I: PinInit<T, E>,
906 F: FnOnce(Pin<&mut T>) -> Result<(), E>, 906 F: FnOnce(Pin<&mut T>) -> Result<(), E>,
907 { 907 {
908 unsafe fn __pinned_init(self, slot: *mut T 908 unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> {
909 // SAFETY: All requirements fulfilled 909 // SAFETY: All requirements fulfilled since this function is `__pinned_init`.
910 unsafe { self.0.__pinned_init(slot)? } 910 unsafe { self.0.__pinned_init(slot)? };
911 // SAFETY: The above call initialized 911 // SAFETY: The above call initialized `slot` and we still have unique access.
912 let val = unsafe { &mut *slot }; 912 let val = unsafe { &mut *slot };
913 // SAFETY: `slot` is considered pinned 913 // SAFETY: `slot` is considered pinned.
914 let val = unsafe { Pin::new_unchecked( 914 let val = unsafe { Pin::new_unchecked(val) };
915 // SAFETY: `slot` was initialized abov 915 // SAFETY: `slot` was initialized above.
916 (self.1)(val).inspect_err(|_| unsafe { 916 (self.1)(val).inspect_err(|_| unsafe { core::ptr::drop_in_place(slot) })
917 } 917 }
918 } 918 }
919 919
920 /// An initializer for `T`. 920 /// An initializer for `T`.
921 /// 921 ///
922 /// To use this initializer, you will need a s 922 /// To use this initializer, you will need a suitable memory location that can hold a `T`. This can
923 /// be [`Box<T>`], [`Arc<T>`], [`UniqueArc<T>` 923 /// be [`Box<T>`], [`Arc<T>`], [`UniqueArc<T>`] or even the stack (see [`stack_pin_init!`]). Use the
924 /// [`InPlaceInit::init`] function of a smart 924 /// [`InPlaceInit::init`] function of a smart pointer like [`Arc<T>`] on this. Because
925 /// [`PinInit<T, E>`] is a super trait, you ca 925 /// [`PinInit<T, E>`] is a super trait, you can use every function that takes it as well.
926 /// 926 ///
927 /// Also see the [module description](self). 927 /// Also see the [module description](self).
928 /// 928 ///
929 /// # Safety 929 /// # Safety
930 /// 930 ///
931 /// When implementing this trait you will need 931 /// When implementing this trait you will need to take great care. Also there are probably very few
932 /// cases where a manual implementation is nec 932 /// cases where a manual implementation is necessary. Use [`init_from_closure`] where possible.
933 /// 933 ///
934 /// The [`Init::__init`] function: 934 /// The [`Init::__init`] function:
935 /// - returns `Ok(())` if it initialized every 935 /// - returns `Ok(())` if it initialized every field of `slot`,
936 /// - returns `Err(err)` if it encountered an 936 /// - returns `Err(err)` if it encountered an error and then cleaned `slot`, this means:
937 /// - `slot` can be deallocated without UB 937 /// - `slot` can be deallocated without UB occurring,
938 /// - `slot` does not need to be dropped, 938 /// - `slot` does not need to be dropped,
939 /// - `slot` is not partially initialized. 939 /// - `slot` is not partially initialized.
940 /// - while constructing the `T` at `slot` it 940 /// - while constructing the `T` at `slot` it upholds the pinning invariants of `T`.
941 /// 941 ///
942 /// The `__pinned_init` function from the supe 942 /// The `__pinned_init` function from the supertrait [`PinInit`] needs to execute the exact same
943 /// code as `__init`. 943 /// code as `__init`.
944 /// 944 ///
945 /// Contrary to its supertype [`PinInit<T, E>` 945 /// Contrary to its supertype [`PinInit<T, E>`] the caller is allowed to
946 /// move the pointee after initialization. 946 /// move the pointee after initialization.
947 /// 947 ///
948 /// [`Arc<T>`]: crate::sync::Arc 948 /// [`Arc<T>`]: crate::sync::Arc
949 #[must_use = "An initializer must be used in o 949 #[must_use = "An initializer must be used in order to create its value."]
950 pub unsafe trait Init<T: ?Sized, E = Infallibl 950 pub unsafe trait Init<T: ?Sized, E = Infallible>: PinInit<T, E> {
951 /// Initializes `slot`. 951 /// Initializes `slot`.
952 /// 952 ///
953 /// # Safety 953 /// # Safety
954 /// 954 ///
955 /// - `slot` is a valid pointer to uniniti 955 /// - `slot` is a valid pointer to uninitialized memory.
956 /// - the caller does not touch `slot` whe 956 /// - the caller does not touch `slot` when `Err` is returned, they are only permitted to
957 /// deallocate. 957 /// deallocate.
958 unsafe fn __init(self, slot: *mut T) -> Re 958 unsafe fn __init(self, slot: *mut T) -> Result<(), E>;
959 959
960 /// First initializes the value using `sel 960 /// First initializes the value using `self` then calls the function `f` with the initialized
961 /// value. 961 /// value.
962 /// 962 ///
963 /// If `f` returns an error the value is d 963 /// If `f` returns an error the value is dropped and the initializer will forward the error.
964 /// 964 ///
965 /// # Examples 965 /// # Examples
966 /// 966 ///
967 /// ```rust 967 /// ```rust
968 /// # #![allow(clippy::disallowed_names)] 968 /// # #![allow(clippy::disallowed_names)]
969 /// use kernel::{types::Opaque, init::{sel 969 /// use kernel::{types::Opaque, init::{self, init_from_closure}};
970 /// struct Foo { 970 /// struct Foo {
971 /// buf: [u8; 1_000_000], 971 /// buf: [u8; 1_000_000],
972 /// } 972 /// }
973 /// 973 ///
974 /// impl Foo { 974 /// impl Foo {
975 /// fn setup(&mut self) { 975 /// fn setup(&mut self) {
976 /// pr_info!("Setting up foo"); 976 /// pr_info!("Setting up foo");
977 /// } 977 /// }
978 /// } 978 /// }
979 /// 979 ///
980 /// let foo = init!(Foo { 980 /// let foo = init!(Foo {
981 /// buf <- init::zeroed() 981 /// buf <- init::zeroed()
982 /// }).chain(|foo| { 982 /// }).chain(|foo| {
983 /// foo.setup(); 983 /// foo.setup();
984 /// Ok(()) 984 /// Ok(())
985 /// }); 985 /// });
986 /// ``` 986 /// ```
987 fn chain<F>(self, f: F) -> ChainInit<Self, 987 fn chain<F>(self, f: F) -> ChainInit<Self, F, T, E>
988 where 988 where
989 F: FnOnce(&mut T) -> Result<(), E>, 989 F: FnOnce(&mut T) -> Result<(), E>,
990 { 990 {
991 ChainInit(self, f, PhantomData) 991 ChainInit(self, f, PhantomData)
992 } 992 }
993 } 993 }
994 994
995 /// An initializer returned by [`Init::chain`] 995 /// An initializer returned by [`Init::chain`].
996 pub struct ChainInit<I, F, T: ?Sized, E>(I, F, 996 pub struct ChainInit<I, F, T: ?Sized, E>(I, F, __internal::Invariant<(E, Box<T>)>);
997 997
998 // SAFETY: The `__init` function is implemente 998 // SAFETY: The `__init` function is implemented such that it
999 // - returns `Ok(())` on successful initializa 999 // - returns `Ok(())` on successful initialization,
1000 // - returns `Err(err)` on error and in this 1000 // - returns `Err(err)` on error and in this case `slot` will be dropped.
1001 unsafe impl<T: ?Sized, E, I, F> Init<T, E> fo 1001 unsafe impl<T: ?Sized, E, I, F> Init<T, E> for ChainInit<I, F, T, E>
1002 where 1002 where
1003 I: Init<T, E>, 1003 I: Init<T, E>,
1004 F: FnOnce(&mut T) -> Result<(), E>, 1004 F: FnOnce(&mut T) -> Result<(), E>,
1005 { 1005 {
1006 unsafe fn __init(self, slot: *mut T) -> R 1006 unsafe fn __init(self, slot: *mut T) -> Result<(), E> {
1007 // SAFETY: All requirements fulfilled 1007 // SAFETY: All requirements fulfilled since this function is `__init`.
1008 unsafe { self.0.__pinned_init(slot)? 1008 unsafe { self.0.__pinned_init(slot)? };
1009 // SAFETY: The above call initialized 1009 // SAFETY: The above call initialized `slot` and we still have unique access.
1010 (self.1)(unsafe { &mut *slot }).inspe 1010 (self.1)(unsafe { &mut *slot }).inspect_err(|_|
1011 // SAFETY: `slot` was initialized 1011 // SAFETY: `slot` was initialized above.
1012 unsafe { core::ptr::drop_in_place 1012 unsafe { core::ptr::drop_in_place(slot) })
1013 } 1013 }
1014 } 1014 }
1015 1015
1016 // SAFETY: `__pinned_init` behaves exactly th 1016 // SAFETY: `__pinned_init` behaves exactly the same as `__init`.
1017 unsafe impl<T: ?Sized, E, I, F> PinInit<T, E> 1017 unsafe impl<T: ?Sized, E, I, F> PinInit<T, E> for ChainInit<I, F, T, E>
1018 where 1018 where
1019 I: Init<T, E>, 1019 I: Init<T, E>,
1020 F: FnOnce(&mut T) -> Result<(), E>, 1020 F: FnOnce(&mut T) -> Result<(), E>,
1021 { 1021 {
1022 unsafe fn __pinned_init(self, slot: *mut 1022 unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> {
1023 // SAFETY: `__init` has less strict r 1023 // SAFETY: `__init` has less strict requirements compared to `__pinned_init`.
1024 unsafe { self.__init(slot) } 1024 unsafe { self.__init(slot) }
1025 } 1025 }
1026 } 1026 }
1027 1027
1028 /// Creates a new [`PinInit<T, E>`] from the 1028 /// Creates a new [`PinInit<T, E>`] from the given closure.
1029 /// 1029 ///
1030 /// # Safety 1030 /// # Safety
1031 /// 1031 ///
1032 /// The closure: 1032 /// The closure:
1033 /// - returns `Ok(())` if it initialized ever 1033 /// - returns `Ok(())` if it initialized every field of `slot`,
1034 /// - returns `Err(err)` if it encountered an 1034 /// - returns `Err(err)` if it encountered an error and then cleaned `slot`, this means:
1035 /// - `slot` can be deallocated without U 1035 /// - `slot` can be deallocated without UB occurring,
1036 /// - `slot` does not need to be dropped, 1036 /// - `slot` does not need to be dropped,
1037 /// - `slot` is not partially initialized 1037 /// - `slot` is not partially initialized.
1038 /// - may assume that the `slot` does not mov 1038 /// - may assume that the `slot` does not move if `T: !Unpin`,
1039 /// - while constructing the `T` at `slot` it 1039 /// - while constructing the `T` at `slot` it upholds the pinning invariants of `T`.
1040 #[inline] 1040 #[inline]
1041 pub const unsafe fn pin_init_from_closure<T: 1041 pub const unsafe fn pin_init_from_closure<T: ?Sized, E>(
1042 f: impl FnOnce(*mut T) -> Result<(), E>, 1042 f: impl FnOnce(*mut T) -> Result<(), E>,
1043 ) -> impl PinInit<T, E> { 1043 ) -> impl PinInit<T, E> {
1044 __internal::InitClosure(f, PhantomData) 1044 __internal::InitClosure(f, PhantomData)
1045 } 1045 }
1046 1046
1047 /// Creates a new [`Init<T, E>`] from the giv 1047 /// Creates a new [`Init<T, E>`] from the given closure.
1048 /// 1048 ///
1049 /// # Safety 1049 /// # Safety
1050 /// 1050 ///
1051 /// The closure: 1051 /// The closure:
1052 /// - returns `Ok(())` if it initialized ever 1052 /// - returns `Ok(())` if it initialized every field of `slot`,
1053 /// - returns `Err(err)` if it encountered an 1053 /// - returns `Err(err)` if it encountered an error and then cleaned `slot`, this means:
1054 /// - `slot` can be deallocated without U 1054 /// - `slot` can be deallocated without UB occurring,
1055 /// - `slot` does not need to be dropped, 1055 /// - `slot` does not need to be dropped,
1056 /// - `slot` is not partially initialized 1056 /// - `slot` is not partially initialized.
1057 /// - the `slot` may move after initializatio 1057 /// - the `slot` may move after initialization.
1058 /// - while constructing the `T` at `slot` it 1058 /// - while constructing the `T` at `slot` it upholds the pinning invariants of `T`.
1059 #[inline] 1059 #[inline]
1060 pub const unsafe fn init_from_closure<T: ?Siz 1060 pub const unsafe fn init_from_closure<T: ?Sized, E>(
1061 f: impl FnOnce(*mut T) -> Result<(), E>, 1061 f: impl FnOnce(*mut T) -> Result<(), E>,
1062 ) -> impl Init<T, E> { 1062 ) -> impl Init<T, E> {
1063 __internal::InitClosure(f, PhantomData) 1063 __internal::InitClosure(f, PhantomData)
1064 } 1064 }
1065 1065
1066 /// An initializer that leaves the memory uni 1066 /// An initializer that leaves the memory uninitialized.
1067 /// 1067 ///
1068 /// The initializer is a no-op. The `slot` me 1068 /// The initializer is a no-op. The `slot` memory is not changed.
1069 #[inline] 1069 #[inline]
1070 pub fn uninit<T, E>() -> impl Init<MaybeUnini 1070 pub fn uninit<T, E>() -> impl Init<MaybeUninit<T>, E> {
1071 // SAFETY: The memory is allowed to be un 1071 // SAFETY: The memory is allowed to be uninitialized.
1072 unsafe { init_from_closure(|_| Ok(())) } 1072 unsafe { init_from_closure(|_| Ok(())) }
1073 } 1073 }
1074 1074
1075 /// Initializes an array by initializing each 1075 /// Initializes an array by initializing each element via the provided initializer.
1076 /// 1076 ///
1077 /// # Examples 1077 /// # Examples
1078 /// 1078 ///
1079 /// ```rust 1079 /// ```rust
1080 /// use kernel::{error::Error, init::init_arr 1080 /// use kernel::{error::Error, init::init_array_from_fn};
1081 /// let array: Box<[usize; 1_000]> = Box::ini 1081 /// let array: Box<[usize; 1_000]> = Box::init::<Error>(init_array_from_fn(|i| i), GFP_KERNEL).unwrap();
1082 /// assert_eq!(array.len(), 1_000); 1082 /// assert_eq!(array.len(), 1_000);
1083 /// ``` 1083 /// ```
1084 pub fn init_array_from_fn<I, const N: usize, 1084 pub fn init_array_from_fn<I, const N: usize, T, E>(
1085 mut make_init: impl FnMut(usize) -> I, 1085 mut make_init: impl FnMut(usize) -> I,
1086 ) -> impl Init<[T; N], E> 1086 ) -> impl Init<[T; N], E>
1087 where 1087 where
1088 I: Init<T, E>, 1088 I: Init<T, E>,
1089 { 1089 {
1090 let init = move |slot: *mut [T; N]| { 1090 let init = move |slot: *mut [T; N]| {
1091 let slot = slot.cast::<T>(); 1091 let slot = slot.cast::<T>();
1092 // Counts the number of initialized e 1092 // Counts the number of initialized elements and when dropped drops that many elements from
1093 // `slot`. 1093 // `slot`.
1094 let mut init_count = ScopeGuard::new_ 1094 let mut init_count = ScopeGuard::new_with_data(0, |i| {
1095 // We now free every element that 1095 // We now free every element that has been initialized before.
1096 // SAFETY: The loop initialized e 1096 // SAFETY: The loop initialized exactly the values from 0..i and since we
1097 // return `Err` below, the caller 1097 // return `Err` below, the caller will consider the memory at `slot` as
1098 // uninitialized. 1098 // uninitialized.
1099 unsafe { ptr::drop_in_place(ptr:: 1099 unsafe { ptr::drop_in_place(ptr::slice_from_raw_parts_mut(slot, i)) };
1100 }); 1100 });
1101 for i in 0..N { 1101 for i in 0..N {
1102 let init = make_init(i); 1102 let init = make_init(i);
1103 // SAFETY: Since 0 <= `i` < N, it 1103 // SAFETY: Since 0 <= `i` < N, it is still in bounds of `[T; N]`.
1104 let ptr = unsafe { slot.add(i) }; 1104 let ptr = unsafe { slot.add(i) };
1105 // SAFETY: The pointer is derived 1105 // SAFETY: The pointer is derived from `slot` and thus satisfies the `__init`
1106 // requirements. 1106 // requirements.
1107 unsafe { init.__init(ptr) }?; 1107 unsafe { init.__init(ptr) }?;
1108 *init_count += 1; 1108 *init_count += 1;
1109 } 1109 }
1110 init_count.dismiss(); 1110 init_count.dismiss();
1111 Ok(()) 1111 Ok(())
1112 }; 1112 };
1113 // SAFETY: The initializer above initiali 1113 // SAFETY: The initializer above initializes every element of the array. On failure it drops
1114 // any initialized elements and returns ` 1114 // any initialized elements and returns `Err`.
1115 unsafe { init_from_closure(init) } 1115 unsafe { init_from_closure(init) }
1116 } 1116 }
1117 1117
1118 /// Initializes an array by initializing each 1118 /// Initializes an array by initializing each element via the provided initializer.
1119 /// 1119 ///
1120 /// # Examples 1120 /// # Examples
1121 /// 1121 ///
1122 /// ```rust 1122 /// ```rust
1123 /// use kernel::{sync::{Arc, Mutex}, init::pi 1123 /// use kernel::{sync::{Arc, Mutex}, init::pin_init_array_from_fn, new_mutex};
1124 /// let array: Arc<[Mutex<usize>; 1_000]> = 1124 /// let array: Arc<[Mutex<usize>; 1_000]> =
1125 /// Arc::pin_init(pin_init_array_from_fn( 1125 /// Arc::pin_init(pin_init_array_from_fn(|i| new_mutex!(i)), GFP_KERNEL).unwrap();
1126 /// assert_eq!(array.len(), 1_000); 1126 /// assert_eq!(array.len(), 1_000);
1127 /// ``` 1127 /// ```
1128 pub fn pin_init_array_from_fn<I, const N: usi 1128 pub fn pin_init_array_from_fn<I, const N: usize, T, E>(
1129 mut make_init: impl FnMut(usize) -> I, 1129 mut make_init: impl FnMut(usize) -> I,
1130 ) -> impl PinInit<[T; N], E> 1130 ) -> impl PinInit<[T; N], E>
1131 where 1131 where
1132 I: PinInit<T, E>, 1132 I: PinInit<T, E>,
1133 { 1133 {
1134 let init = move |slot: *mut [T; N]| { 1134 let init = move |slot: *mut [T; N]| {
1135 let slot = slot.cast::<T>(); 1135 let slot = slot.cast::<T>();
1136 // Counts the number of initialized e 1136 // Counts the number of initialized elements and when dropped drops that many elements from
1137 // `slot`. 1137 // `slot`.
1138 let mut init_count = ScopeGuard::new_ 1138 let mut init_count = ScopeGuard::new_with_data(0, |i| {
1139 // We now free every element that 1139 // We now free every element that has been initialized before.
1140 // SAFETY: The loop initialized e 1140 // SAFETY: The loop initialized exactly the values from 0..i and since we
1141 // return `Err` below, the caller 1141 // return `Err` below, the caller will consider the memory at `slot` as
1142 // uninitialized. 1142 // uninitialized.
1143 unsafe { ptr::drop_in_place(ptr:: 1143 unsafe { ptr::drop_in_place(ptr::slice_from_raw_parts_mut(slot, i)) };
1144 }); 1144 });
1145 for i in 0..N { 1145 for i in 0..N {
1146 let init = make_init(i); 1146 let init = make_init(i);
1147 // SAFETY: Since 0 <= `i` < N, it 1147 // SAFETY: Since 0 <= `i` < N, it is still in bounds of `[T; N]`.
1148 let ptr = unsafe { slot.add(i) }; 1148 let ptr = unsafe { slot.add(i) };
1149 // SAFETY: The pointer is derived 1149 // SAFETY: The pointer is derived from `slot` and thus satisfies the `__init`
1150 // requirements. 1150 // requirements.
1151 unsafe { init.__pinned_init(ptr) 1151 unsafe { init.__pinned_init(ptr) }?;
1152 *init_count += 1; 1152 *init_count += 1;
1153 } 1153 }
1154 init_count.dismiss(); 1154 init_count.dismiss();
1155 Ok(()) 1155 Ok(())
1156 }; 1156 };
1157 // SAFETY: The initializer above initiali 1157 // SAFETY: The initializer above initializes every element of the array. On failure it drops
1158 // any initialized elements and returns ` 1158 // any initialized elements and returns `Err`.
1159 unsafe { pin_init_from_closure(init) } 1159 unsafe { pin_init_from_closure(init) }
1160 } 1160 }
1161 1161
1162 // SAFETY: Every type can be initialized by-v 1162 // SAFETY: Every type can be initialized by-value.
1163 unsafe impl<T, E> Init<T, E> for T { 1163 unsafe impl<T, E> Init<T, E> for T {
1164 unsafe fn __init(self, slot: *mut T) -> R 1164 unsafe fn __init(self, slot: *mut T) -> Result<(), E> {
1165 unsafe { slot.write(self) }; 1165 unsafe { slot.write(self) };
1166 Ok(()) 1166 Ok(())
1167 } 1167 }
1168 } 1168 }
1169 1169
1170 // SAFETY: Every type can be initialized by-v 1170 // SAFETY: Every type can be initialized by-value. `__pinned_init` calls `__init`.
1171 unsafe impl<T, E> PinInit<T, E> for T { 1171 unsafe impl<T, E> PinInit<T, E> for T {
1172 unsafe fn __pinned_init(self, slot: *mut 1172 unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> {
1173 unsafe { self.__init(slot) } 1173 unsafe { self.__init(slot) }
1174 } 1174 }
1175 } 1175 }
1176 1176
1177 /// Smart pointer that can initialize memory 1177 /// Smart pointer that can initialize memory in-place.
1178 pub trait InPlaceInit<T>: Sized { 1178 pub trait InPlaceInit<T>: Sized {
1179 /// Pinned version of `Self`. 1179 /// Pinned version of `Self`.
1180 /// 1180 ///
1181 /// If a type already implicitly pins its 1181 /// If a type already implicitly pins its pointee, `Pin<Self>` is unnecessary. In this case use
1182 /// `Self`, otherwise just use `Pin<Self> 1182 /// `Self`, otherwise just use `Pin<Self>`.
1183 type PinnedSelf; 1183 type PinnedSelf;
1184 1184
1185 /// Use the given pin-initializer to pin- 1185 /// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this
1186 /// type. 1186 /// type.
1187 /// 1187 ///
1188 /// If `T: !Unpin` it will not be able to 1188 /// If `T: !Unpin` it will not be able to move afterwards.
1189 fn try_pin_init<E>(init: impl PinInit<T, 1189 fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Self::PinnedSelf, E>
1190 where 1190 where
1191 E: From<AllocError>; 1191 E: From<AllocError>;
1192 1192
1193 /// Use the given pin-initializer to pin- 1193 /// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this
1194 /// type. 1194 /// type.
1195 /// 1195 ///
1196 /// If `T: !Unpin` it will not be able to 1196 /// If `T: !Unpin` it will not be able to move afterwards.
1197 fn pin_init<E>(init: impl PinInit<T, E>, 1197 fn pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> error::Result<Self::PinnedSelf>
1198 where 1198 where
1199 Error: From<E>, 1199 Error: From<E>,
1200 { 1200 {
1201 // SAFETY: We delegate to `init` and 1201 // SAFETY: We delegate to `init` and only change the error type.
1202 let init = unsafe { 1202 let init = unsafe {
1203 pin_init_from_closure(|slot| init 1203 pin_init_from_closure(|slot| init.__pinned_init(slot).map_err(|e| Error::from(e)))
1204 }; 1204 };
1205 Self::try_pin_init(init, flags) 1205 Self::try_pin_init(init, flags)
1206 } 1206 }
1207 1207
1208 /// Use the given initializer to in-place 1208 /// Use the given initializer to in-place initialize a `T`.
1209 fn try_init<E>(init: impl Init<T, E>, fla 1209 fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
1210 where 1210 where
1211 E: From<AllocError>; 1211 E: From<AllocError>;
1212 1212
1213 /// Use the given initializer to in-place 1213 /// Use the given initializer to in-place initialize a `T`.
1214 fn init<E>(init: impl Init<T, E>, flags: 1214 fn init<E>(init: impl Init<T, E>, flags: Flags) -> error::Result<Self>
1215 where 1215 where
1216 Error: From<E>, 1216 Error: From<E>,
1217 { 1217 {
1218 // SAFETY: We delegate to `init` and 1218 // SAFETY: We delegate to `init` and only change the error type.
1219 let init = unsafe { 1219 let init = unsafe {
1220 init_from_closure(|slot| init.__p 1220 init_from_closure(|slot| init.__pinned_init(slot).map_err(|e| Error::from(e)))
1221 }; 1221 };
1222 Self::try_init(init, flags) 1222 Self::try_init(init, flags)
1223 } 1223 }
1224 } 1224 }
1225 1225
1226 impl<T> InPlaceInit<T> for Arc<T> { 1226 impl<T> InPlaceInit<T> for Arc<T> {
1227 type PinnedSelf = Self; 1227 type PinnedSelf = Self;
1228 1228
1229 #[inline] 1229 #[inline]
1230 fn try_pin_init<E>(init: impl PinInit<T, 1230 fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Self::PinnedSelf, E>
1231 where 1231 where
1232 E: From<AllocError>, 1232 E: From<AllocError>,
1233 { 1233 {
1234 UniqueArc::try_pin_init(init, flags). 1234 UniqueArc::try_pin_init(init, flags).map(|u| u.into())
1235 } 1235 }
1236 1236
1237 #[inline] 1237 #[inline]
1238 fn try_init<E>(init: impl Init<T, E>, fla 1238 fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
1239 where 1239 where
1240 E: From<AllocError>, 1240 E: From<AllocError>,
1241 { 1241 {
1242 UniqueArc::try_init(init, flags).map( 1242 UniqueArc::try_init(init, flags).map(|u| u.into())
1243 } 1243 }
1244 } 1244 }
1245 1245
1246 impl<T> InPlaceInit<T> for Box<T> { 1246 impl<T> InPlaceInit<T> for Box<T> {
1247 type PinnedSelf = Pin<Self>; 1247 type PinnedSelf = Pin<Self>;
1248 1248
1249 #[inline] 1249 #[inline]
1250 fn try_pin_init<E>(init: impl PinInit<T, 1250 fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Self::PinnedSelf, E>
1251 where 1251 where
1252 E: From<AllocError>, 1252 E: From<AllocError>,
1253 { 1253 {
1254 <Box<_> as BoxExt<_>>::new_uninit(fla 1254 <Box<_> as BoxExt<_>>::new_uninit(flags)?.write_pin_init(init)
1255 } 1255 }
1256 1256
1257 #[inline] 1257 #[inline]
1258 fn try_init<E>(init: impl Init<T, E>, fla 1258 fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
1259 where 1259 where
1260 E: From<AllocError>, 1260 E: From<AllocError>,
1261 { 1261 {
1262 <Box<_> as BoxExt<_>>::new_uninit(fla 1262 <Box<_> as BoxExt<_>>::new_uninit(flags)?.write_init(init)
1263 } 1263 }
1264 } 1264 }
1265 1265
1266 impl<T> InPlaceInit<T> for UniqueArc<T> { 1266 impl<T> InPlaceInit<T> for UniqueArc<T> {
1267 type PinnedSelf = Pin<Self>; 1267 type PinnedSelf = Pin<Self>;
1268 1268
1269 #[inline] 1269 #[inline]
1270 fn try_pin_init<E>(init: impl PinInit<T, 1270 fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Self::PinnedSelf, E>
1271 where 1271 where
1272 E: From<AllocError>, 1272 E: From<AllocError>,
1273 { 1273 {
1274 UniqueArc::new_uninit(flags)?.write_p 1274 UniqueArc::new_uninit(flags)?.write_pin_init(init)
1275 } 1275 }
1276 1276
1277 #[inline] 1277 #[inline]
1278 fn try_init<E>(init: impl Init<T, E>, fla 1278 fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
1279 where 1279 where
1280 E: From<AllocError>, 1280 E: From<AllocError>,
1281 { 1281 {
1282 UniqueArc::new_uninit(flags)?.write_i 1282 UniqueArc::new_uninit(flags)?.write_init(init)
1283 } 1283 }
1284 } 1284 }
1285 1285
1286 /// Smart pointer containing uninitialized me 1286 /// Smart pointer containing uninitialized memory and that can write a value.
1287 pub trait InPlaceWrite<T> { 1287 pub trait InPlaceWrite<T> {
1288 /// The type `Self` turns into when the c 1288 /// The type `Self` turns into when the contents are initialized.
1289 type Initialized; 1289 type Initialized;
1290 1290
1291 /// Use the given initializer to write a 1291 /// Use the given initializer to write a value into `self`.
1292 /// 1292 ///
1293 /// Does not drop the current value and c 1293 /// Does not drop the current value and considers it as uninitialized memory.
1294 fn write_init<E>(self, init: impl Init<T, 1294 fn write_init<E>(self, init: impl Init<T, E>) -> Result<Self::Initialized, E>;
1295 1295
1296 /// Use the given pin-initializer to writ 1296 /// Use the given pin-initializer to write a value into `self`.
1297 /// 1297 ///
1298 /// Does not drop the current value and c 1298 /// Does not drop the current value and considers it as uninitialized memory.
1299 fn write_pin_init<E>(self, init: impl Pin 1299 fn write_pin_init<E>(self, init: impl PinInit<T, E>) -> Result<Pin<Self::Initialized>, E>;
1300 } 1300 }
1301 1301
1302 impl<T> InPlaceWrite<T> for Box<MaybeUninit<T 1302 impl<T> InPlaceWrite<T> for Box<MaybeUninit<T>> {
1303 type Initialized = Box<T>; 1303 type Initialized = Box<T>;
1304 1304
1305 fn write_init<E>(mut self, init: impl Ini 1305 fn write_init<E>(mut self, init: impl Init<T, E>) -> Result<Self::Initialized, E> {
1306 let slot = self.as_mut_ptr(); 1306 let slot = self.as_mut_ptr();
1307 // SAFETY: When init errors/panics, s 1307 // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
1308 // slot is valid. 1308 // slot is valid.
1309 unsafe { init.__init(slot)? }; 1309 unsafe { init.__init(slot)? };
1310 // SAFETY: All fields have been initi 1310 // SAFETY: All fields have been initialized.
1311 Ok(unsafe { self.assume_init() }) 1311 Ok(unsafe { self.assume_init() })
1312 } 1312 }
1313 1313
1314 fn write_pin_init<E>(mut self, init: impl 1314 fn write_pin_init<E>(mut self, init: impl PinInit<T, E>) -> Result<Pin<Self::Initialized>, E> {
1315 let slot = self.as_mut_ptr(); 1315 let slot = self.as_mut_ptr();
1316 // SAFETY: When init errors/panics, s 1316 // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
1317 // slot is valid and will not be move 1317 // slot is valid and will not be moved, because we pin it later.
1318 unsafe { init.__pinned_init(slot)? }; 1318 unsafe { init.__pinned_init(slot)? };
1319 // SAFETY: All fields have been initi 1319 // SAFETY: All fields have been initialized.
1320 Ok(unsafe { self.assume_init() }.into 1320 Ok(unsafe { self.assume_init() }.into())
1321 } 1321 }
1322 } 1322 }
1323 1323
1324 impl<T> InPlaceWrite<T> for UniqueArc<MaybeUn 1324 impl<T> InPlaceWrite<T> for UniqueArc<MaybeUninit<T>> {
1325 type Initialized = UniqueArc<T>; 1325 type Initialized = UniqueArc<T>;
1326 1326
1327 fn write_init<E>(mut self, init: impl Ini 1327 fn write_init<E>(mut self, init: impl Init<T, E>) -> Result<Self::Initialized, E> {
1328 let slot = self.as_mut_ptr(); 1328 let slot = self.as_mut_ptr();
1329 // SAFETY: When init errors/panics, s 1329 // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
1330 // slot is valid. 1330 // slot is valid.
1331 unsafe { init.__init(slot)? }; 1331 unsafe { init.__init(slot)? };
1332 // SAFETY: All fields have been initi 1332 // SAFETY: All fields have been initialized.
1333 Ok(unsafe { self.assume_init() }) 1333 Ok(unsafe { self.assume_init() })
1334 } 1334 }
1335 1335
1336 fn write_pin_init<E>(mut self, init: impl 1336 fn write_pin_init<E>(mut self, init: impl PinInit<T, E>) -> Result<Pin<Self::Initialized>, E> {
1337 let slot = self.as_mut_ptr(); 1337 let slot = self.as_mut_ptr();
1338 // SAFETY: When init errors/panics, s 1338 // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
1339 // slot is valid and will not be move 1339 // slot is valid and will not be moved, because we pin it later.
1340 unsafe { init.__pinned_init(slot)? }; 1340 unsafe { init.__pinned_init(slot)? };
1341 // SAFETY: All fields have been initi 1341 // SAFETY: All fields have been initialized.
1342 Ok(unsafe { self.assume_init() }.into 1342 Ok(unsafe { self.assume_init() }.into())
1343 } 1343 }
1344 } 1344 }
1345 1345
1346 /// Trait facilitating pinned destruction. 1346 /// Trait facilitating pinned destruction.
1347 /// 1347 ///
1348 /// Use [`pinned_drop`] to implement this tra 1348 /// Use [`pinned_drop`] to implement this trait safely:
1349 /// 1349 ///
1350 /// ```rust 1350 /// ```rust
1351 /// # use kernel::sync::Mutex; 1351 /// # use kernel::sync::Mutex;
1352 /// use kernel::macros::pinned_drop; 1352 /// use kernel::macros::pinned_drop;
1353 /// use core::pin::Pin; 1353 /// use core::pin::Pin;
1354 /// #[pin_data(PinnedDrop)] 1354 /// #[pin_data(PinnedDrop)]
1355 /// struct Foo { 1355 /// struct Foo {
1356 /// #[pin] 1356 /// #[pin]
1357 /// mtx: Mutex<usize>, 1357 /// mtx: Mutex<usize>,
1358 /// } 1358 /// }
1359 /// 1359 ///
1360 /// #[pinned_drop] 1360 /// #[pinned_drop]
1361 /// impl PinnedDrop for Foo { 1361 /// impl PinnedDrop for Foo {
1362 /// fn drop(self: Pin<&mut Self>) { 1362 /// fn drop(self: Pin<&mut Self>) {
1363 /// pr_info!("Foo is being dropped!") 1363 /// pr_info!("Foo is being dropped!");
1364 /// } 1364 /// }
1365 /// } 1365 /// }
1366 /// ``` 1366 /// ```
1367 /// 1367 ///
1368 /// # Safety 1368 /// # Safety
1369 /// 1369 ///
1370 /// This trait must be implemented via the [` 1370 /// This trait must be implemented via the [`pinned_drop`] proc-macro attribute on the impl.
1371 /// 1371 ///
1372 /// [`pinned_drop`]: kernel::macros::pinned_d 1372 /// [`pinned_drop`]: kernel::macros::pinned_drop
1373 pub unsafe trait PinnedDrop: __internal::HasP 1373 pub unsafe trait PinnedDrop: __internal::HasPinData {
1374 /// Executes the pinned destructor of thi 1374 /// Executes the pinned destructor of this type.
1375 /// 1375 ///
1376 /// While this function is marked safe, i 1376 /// While this function is marked safe, it is actually unsafe to call it manually. For this
1377 /// reason it takes an additional paramet 1377 /// reason it takes an additional parameter. This type can only be constructed by `unsafe` code
1378 /// and thus prevents this function from 1378 /// and thus prevents this function from being called where it should not.
1379 /// 1379 ///
1380 /// This extra parameter will be generate 1380 /// This extra parameter will be generated by the `#[pinned_drop]` proc-macro attribute
1381 /// automatically. 1381 /// automatically.
1382 fn drop(self: Pin<&mut Self>, only_call_f 1382 fn drop(self: Pin<&mut Self>, only_call_from_drop: __internal::OnlyCallFromDrop);
1383 } 1383 }
1384 1384
1385 /// Marker trait for types that can be initia 1385 /// Marker trait for types that can be initialized by writing just zeroes.
1386 /// 1386 ///
1387 /// # Safety 1387 /// # Safety
1388 /// 1388 ///
1389 /// The bit pattern consisting of only zeroes 1389 /// The bit pattern consisting of only zeroes is a valid bit pattern for this type. In other words,
1390 /// this is not UB: 1390 /// this is not UB:
1391 /// 1391 ///
1392 /// ```rust,ignore 1392 /// ```rust,ignore
1393 /// let val: Self = unsafe { core::mem::zeroe 1393 /// let val: Self = unsafe { core::mem::zeroed() };
1394 /// ``` 1394 /// ```
1395 pub unsafe trait Zeroable {} 1395 pub unsafe trait Zeroable {}
1396 1396
1397 /// Create a new zeroed T. 1397 /// Create a new zeroed T.
1398 /// 1398 ///
1399 /// The returned initializer will write `0x00 1399 /// The returned initializer will write `0x00` to every byte of the given `slot`.
1400 #[inline] 1400 #[inline]
1401 pub fn zeroed<T: Zeroable>() -> impl Init<T> 1401 pub fn zeroed<T: Zeroable>() -> impl Init<T> {
1402 // SAFETY: Because `T: Zeroable`, all byt 1402 // SAFETY: Because `T: Zeroable`, all bytes zero is a valid bit pattern for `T`
1403 // and because we write all zeroes, the m 1403 // and because we write all zeroes, the memory is initialized.
1404 unsafe { 1404 unsafe {
1405 init_from_closure(|slot: *mut T| { 1405 init_from_closure(|slot: *mut T| {
1406 slot.write_bytes(0, 1); 1406 slot.write_bytes(0, 1);
1407 Ok(()) 1407 Ok(())
1408 }) 1408 })
1409 } 1409 }
1410 } 1410 }
1411 1411
1412 macro_rules! impl_zeroable { 1412 macro_rules! impl_zeroable {
1413 ($($({$($generics:tt)*})? $t:ty, )*) => { 1413 ($($({$($generics:tt)*})? $t:ty, )*) => {
1414 $(unsafe impl$($($generics)*)? Zeroab 1414 $(unsafe impl$($($generics)*)? Zeroable for $t {})*
1415 }; 1415 };
1416 } 1416 }
1417 1417
1418 impl_zeroable! { 1418 impl_zeroable! {
1419 // SAFETY: All primitives that are allowe 1419 // SAFETY: All primitives that are allowed to be zero.
1420 bool, 1420 bool,
1421 char, 1421 char,
1422 u8, u16, u32, u64, u128, usize, 1422 u8, u16, u32, u64, u128, usize,
1423 i8, i16, i32, i64, i128, isize, 1423 i8, i16, i32, i64, i128, isize,
1424 f32, f64, 1424 f32, f64,
1425 1425
1426 // Note: do not add uninhabited types (su 1426 // Note: do not add uninhabited types (such as `!` or `core::convert::Infallible`) to this list;
1427 // creating an instance of an uninhabited 1427 // creating an instance of an uninhabited type is immediate undefined behavior. For more on
1428 // uninhabited/empty types, consult The R 1428 // uninhabited/empty types, consult The Rustonomicon:
1429 // <https://doc.rust-lang.org/stable/nomi 1429 // <https://doc.rust-lang.org/stable/nomicon/exotic-sizes.html#empty-types>. The Rust Reference
1430 // also has information on undefined beha 1430 // also has information on undefined behavior:
1431 // <https://doc.rust-lang.org/stable/refe 1431 // <https://doc.rust-lang.org/stable/reference/behavior-considered-undefined.html>.
1432 // 1432 //
1433 // SAFETY: These are inhabited ZSTs; ther 1433 // SAFETY: These are inhabited ZSTs; there is nothing to zero and a valid value exists.
1434 {<T: ?Sized>} PhantomData<T>, core::marke 1434 {<T: ?Sized>} PhantomData<T>, core::marker::PhantomPinned, (),
1435 1435
1436 // SAFETY: Type is allowed to take any va 1436 // SAFETY: Type is allowed to take any value, including all zeros.
1437 {<T>} MaybeUninit<T>, 1437 {<T>} MaybeUninit<T>,
1438 // SAFETY: Type is allowed to take any va 1438 // SAFETY: Type is allowed to take any value, including all zeros.
1439 {<T>} Opaque<T>, 1439 {<T>} Opaque<T>,
1440 1440
1441 // SAFETY: `T: Zeroable` and `UnsafeCell` 1441 // SAFETY: `T: Zeroable` and `UnsafeCell` is `repr(transparent)`.
1442 {<T: ?Sized + Zeroable>} UnsafeCell<T>, 1442 {<T: ?Sized + Zeroable>} UnsafeCell<T>,
1443 1443
1444 // SAFETY: All zeros is equivalent to `No 1444 // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee).
1445 Option<NonZeroU8>, Option<NonZeroU16>, Op 1445 Option<NonZeroU8>, Option<NonZeroU16>, Option<NonZeroU32>, Option<NonZeroU64>,
1446 Option<NonZeroU128>, Option<NonZeroUsize> 1446 Option<NonZeroU128>, Option<NonZeroUsize>,
1447 Option<NonZeroI8>, Option<NonZeroI16>, Op 1447 Option<NonZeroI8>, Option<NonZeroI16>, Option<NonZeroI32>, Option<NonZeroI64>,
1448 Option<NonZeroI128>, Option<NonZeroIsize> 1448 Option<NonZeroI128>, Option<NonZeroIsize>,
1449 1449
1450 // SAFETY: All zeros is equivalent to `No 1450 // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee).
1451 // 1451 //
1452 // In this case we are allowed to use `T: 1452 // In this case we are allowed to use `T: ?Sized`, since all zeros is the `None` variant.
1453 {<T: ?Sized>} Option<NonNull<T>>, 1453 {<T: ?Sized>} Option<NonNull<T>>,
1454 {<T: ?Sized>} Option<Box<T>>, 1454 {<T: ?Sized>} Option<Box<T>>,
1455 1455
1456 // SAFETY: `null` pointer is valid. 1456 // SAFETY: `null` pointer is valid.
1457 // 1457 //
1458 // We cannot use `T: ?Sized`, since the V 1458 // We cannot use `T: ?Sized`, since the VTABLE pointer part of fat pointers is not allowed to be
1459 // null. 1459 // null.
1460 // 1460 //
1461 // When `Pointee` gets stabilized, we cou 1461 // When `Pointee` gets stabilized, we could use
1462 // `T: ?Sized where <T as Pointee>::Metad 1462 // `T: ?Sized where <T as Pointee>::Metadata: Zeroable`
1463 {<T>} *mut T, {<T>} *const T, 1463 {<T>} *mut T, {<T>} *const T,
1464 1464
1465 // SAFETY: `null` pointer is valid and th 1465 // SAFETY: `null` pointer is valid and the metadata part of these fat pointers is allowed to be
1466 // zero. 1466 // zero.
1467 {<T>} *mut [T], {<T>} *const [T], *mut st 1467 {<T>} *mut [T], {<T>} *const [T], *mut str, *const str,
1468 1468
1469 // SAFETY: `T` is `Zeroable`. 1469 // SAFETY: `T` is `Zeroable`.
1470 {<const N: usize, T: Zeroable>} [T; N], { 1470 {<const N: usize, T: Zeroable>} [T; N], {<T: Zeroable>} Wrapping<T>,
1471 } 1471 }
1472 1472
1473 macro_rules! impl_tuple_zeroable { 1473 macro_rules! impl_tuple_zeroable {
1474 ($(,)?) => {}; 1474 ($(,)?) => {};
1475 ($first:ident, $($t:ident),* $(,)?) => { 1475 ($first:ident, $($t:ident),* $(,)?) => {
1476 // SAFETY: All elements are zeroable 1476 // SAFETY: All elements are zeroable and padding can be zero.
1477 unsafe impl<$first: Zeroable, $($t: Z 1477 unsafe impl<$first: Zeroable, $($t: Zeroable),*> Zeroable for ($first, $($t),*) {}
1478 impl_tuple_zeroable!($($t),* ,); 1478 impl_tuple_zeroable!($($t),* ,);
1479 } 1479 }
1480 } 1480 }
1481 1481
1482 impl_tuple_zeroable!(A, B, C, D, E, F, G, H, 1482 impl_tuple_zeroable!(A, B, C, D, E, F, G, H, I, J);
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