1 /* SPDX-License-Identifier: GPL-2.0-only */ 1
2 /*
3 * Copyright (C) 2024, SUSE LLC
4 *
5 * Authors: Enzo Matsumiya <ematsumiya@suse.de
6 *
7 * This file implements I/O compression suppor
8 * See compress/ for implementation details of
9 *
10 * References:
11 * MS-SMB2 "3.1.4.4 Compressing the Message" -
12 * MS-SMB2 "3.1.5.3 Decompressing the Chained
13 * MS-XCA - for details of the supported algor
14 */
15 #ifndef _SMB_COMPRESS_H
16 #define _SMB_COMPRESS_H
17
18 #include <linux/uio.h>
19 #include <linux/kernel.h>
20 #include "../common/smb2pdu.h"
21 #include "cifsglob.h"
22
23 /* sizeof(smb2_compression_hdr) - sizeof(Origi
24 #define SMB_COMPRESS_HDR_LEN 16
25 /* sizeof(smb2_compression_payload_hdr) - size
26 #define SMB_COMPRESS_PAYLOAD_HDR_LEN 8
27 #define SMB_COMPRESS_MIN_LEN PAGE_S
28
29 #ifdef CONFIG_CIFS_COMPRESSION
30 typedef int (*compress_send_fn)(struct TCP_Ser
31
32 int smb_compress(struct TCP_Server_Info *serve
33
34 /**
35 * should_compress() - Determines if a request
36 * request (read) should b
37 * @tcon: tcon of the request is being sent to
38 * @rqst: request to evaluate
39 *
40 * Return: true iff:
41 * - compression was successfully negotiated w
42 * - server has enabled compression for the sh
43 * - it's a read or write request
44 * - (write only) request length is >= SMB_COM
45 * - (write only) is_compressible() returns 1
46 *
47 * Return false otherwise.
48 */
49 bool should_compress(const struct cifs_tcon *t
50
51 /**
52 * smb_compress_alg_valid() - Validate a compr
53 * @alg: Compression algorithm to check.
54 * @valid_none: Conditional check whether NONE
55 * considered valid or not.
56 *
57 * If @alg is SMB3_COMPRESS_NONE, this functio
58 *
59 * Note that 'NONE' (0) compressor type is con
60 * negotiation, as it's never requested to/ret
61 *
62 * Return: true if @alg is valid/supported, fa
63 */
64 static __always_inline int smb_compress_alg_va
65 {
66 if (alg == SMB3_COMPRESS_NONE)
67 return valid_none;
68
69 if (alg == SMB3_COMPRESS_LZ77 || alg =
70 return true;
71
72 return false;
73 }
74 #else /* !CONFIG_CIFS_COMPRESSION */
75 static inline int smb_compress(void *unused1,
76 {
77 return -EOPNOTSUPP;
78 }
79
80 static inline bool should_compress(void *unuse
81 {
82 return false;
83 }
84
85 static inline int smb_compress_alg_valid(__le1
86 {
87 return -EOPNOTSUPP;
88 }
89 #endif /* !CONFIG_CIFS_COMPRESSION */
90 #endif /* _SMB_COMPRESS_H */
91
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