1 #include <linux/kernel.h>
2 #include <linux/errno.h>
3 #include <linux/file.h>
4 #include <linux/slab.h>
5 #include <linux/net.h>
6 #include <linux/io_uring.h>
7
8 #include "io_uring.h"
9 #include "notif.h"
10 #include "rsrc.h"
11
12 static const struct ubuf_info_ops io_ubuf_ops;
13
14 static void io_notif_tw_complete(struct io_kiocb *notif, struct io_tw_state *ts)
15 {
16 struct io_notif_data *nd = io_notif_to_data(notif);
17
18 do {
19 notif = cmd_to_io_kiocb(nd);
20
21 lockdep_assert(refcount_read(&nd->uarg.refcnt) == 0);
22
23 if (unlikely(nd->zc_report) && (nd->zc_copied || !nd->zc_used))
24 notif->cqe.res |= IORING_NOTIF_USAGE_ZC_COPIED;
25
26 if (nd->account_pages && notif->ctx->user) {
27 __io_unaccount_mem(notif->ctx->user, nd->account_pages);
28 nd->account_pages = 0;
29 }
30
31 nd = nd->next;
32 io_req_task_complete(notif, ts);
33 } while (nd);
34 }
35
36 void io_tx_ubuf_complete(struct sk_buff *skb, struct ubuf_info *uarg,
37 bool success)
38 {
39 struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg);
40 struct io_kiocb *notif = cmd_to_io_kiocb(nd);
41 unsigned tw_flags;
42
43 if (nd->zc_report) {
44 if (success && !nd->zc_used && skb)
45 WRITE_ONCE(nd->zc_used, true);
46 else if (!success && !nd->zc_copied)
47 WRITE_ONCE(nd->zc_copied, true);
48 }
49
50 if (!refcount_dec_and_test(&uarg->refcnt))
51 return;
52
53 if (nd->head != nd) {
54 io_tx_ubuf_complete(skb, &nd->head->uarg, success);
55 return;
56 }
57
58 tw_flags = nd->next ? 0 : IOU_F_TWQ_LAZY_WAKE;
59 notif->io_task_work.func = io_notif_tw_complete;
60 __io_req_task_work_add(notif, tw_flags);
61 }
62
63 static int io_link_skb(struct sk_buff *skb, struct ubuf_info *uarg)
64 {
65 struct io_notif_data *nd, *prev_nd;
66 struct io_kiocb *prev_notif, *notif;
67 struct ubuf_info *prev_uarg = skb_zcopy(skb);
68
69 nd = container_of(uarg, struct io_notif_data, uarg);
70 notif = cmd_to_io_kiocb(nd);
71
72 if (!prev_uarg) {
73 net_zcopy_get(&nd->uarg);
74 skb_zcopy_init(skb, &nd->uarg);
75 return 0;
76 }
77 /* handle it separately as we can't link a notif to itself */
78 if (unlikely(prev_uarg == &nd->uarg))
79 return 0;
80 /* we can't join two links together, just request a fresh skb */
81 if (unlikely(nd->head != nd || nd->next))
82 return -EEXIST;
83 /* don't mix zc providers */
84 if (unlikely(prev_uarg->ops != &io_ubuf_ops))
85 return -EEXIST;
86
87 prev_nd = container_of(prev_uarg, struct io_notif_data, uarg);
88 prev_notif = cmd_to_io_kiocb(nd);
89
90 /* make sure all noifications can be finished in the same task_work */
91 if (unlikely(notif->ctx != prev_notif->ctx ||
92 notif->task != prev_notif->task))
93 return -EEXIST;
94
95 nd->head = prev_nd->head;
96 nd->next = prev_nd->next;
97 prev_nd->next = nd;
98 net_zcopy_get(&nd->head->uarg);
99 return 0;
100 }
101
102 static const struct ubuf_info_ops io_ubuf_ops = {
103 .complete = io_tx_ubuf_complete,
104 .link_skb = io_link_skb,
105 };
106
107 struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx)
108 __must_hold(&ctx->uring_lock)
109 {
110 struct io_kiocb *notif;
111 struct io_notif_data *nd;
112
113 if (unlikely(!io_alloc_req(ctx, ¬if)))
114 return NULL;
115 notif->opcode = IORING_OP_NOP;
116 notif->flags = 0;
117 notif->file = NULL;
118 notif->task = current;
119 io_get_task_refs(1);
120 notif->rsrc_node = NULL;
121
122 nd = io_notif_to_data(notif);
123 nd->zc_report = false;
124 nd->account_pages = 0;
125 nd->next = NULL;
126 nd->head = nd;
127
128 nd->uarg.flags = IO_NOTIF_UBUF_FLAGS;
129 nd->uarg.ops = &io_ubuf_ops;
130 refcount_set(&nd->uarg.refcnt, 1);
131 return notif;
132 }
133
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