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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _LINUX_PIPE_FS_I_H |
3 | #define _LINUX_PIPE_FS_I_H | |
4 | ||
35f3d14d | 5 | #define PIPE_DEF_BUFFERS 16 |
1da177e4 | 6 | |
1432873a JA |
7 | #define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */ |
8 | #define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */ | |
9 | #define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */ | |
9883035a | 10 | #define PIPE_BUF_FLAG_PACKET 0x08 /* read() as a packet */ |
3e7ee3e7 | 11 | |
0845718d JA |
12 | /** |
13 | * struct pipe_buffer - a linux kernel pipe buffer | |
14 | * @page: the page containing the data for the pipe buffer | |
15 | * @offset: offset of data inside the @page | |
16 | * @len: length of data inside the @page | |
17 | * @ops: operations associated with this buffer. See @pipe_buf_operations. | |
18 | * @flags: pipe buffer flags. See above. | |
19 | * @private: private data owned by the ops. | |
20 | **/ | |
1da177e4 LT |
21 | struct pipe_buffer { |
22 | struct page *page; | |
23 | unsigned int offset, len; | |
d4c3cca9 | 24 | const struct pipe_buf_operations *ops; |
3e7ee3e7 | 25 | unsigned int flags; |
497f9625 | 26 | unsigned long private; |
1da177e4 LT |
27 | }; |
28 | ||
0845718d JA |
29 | /** |
30 | * struct pipe_inode_info - a linux kernel pipe | |
72b0d9aa | 31 | * @mutex: mutex protecting the whole thing |
0845718d JA |
32 | * @wait: reader/writer wait point in case of empty/full pipe |
33 | * @nrbufs: the number of non-empty pipe buffers in this pipe | |
0dc14885 | 34 | * @buffers: total number of buffers (should be a power of 2) |
0845718d JA |
35 | * @curbuf: the current pipe buffer entry |
36 | * @tmp_page: cached released page | |
37 | * @readers: number of current readers of this pipe | |
38 | * @writers: number of current writers of this pipe | |
e227867f | 39 | * @files: number of struct file referring this pipe (protected by ->i_lock) |
0845718d JA |
40 | * @waiting_writers: number of writers blocked waiting for room |
41 | * @r_counter: reader counter | |
42 | * @w_counter: writer counter | |
43 | * @fasync_readers: reader side fasync | |
44 | * @fasync_writers: writer side fasync | |
0845718d | 45 | * @bufs: the circular array of pipe buffers |
759c0114 | 46 | * @user: the user who created this pipe |
0845718d | 47 | **/ |
17374ff1 | 48 | struct pipe_inode_info { |
72b0d9aa | 49 | struct mutex mutex; |
17374ff1 | 50 | wait_queue_head_t wait; |
35f3d14d | 51 | unsigned int nrbufs, curbuf, buffers; |
17374ff1 JA |
52 | unsigned int readers; |
53 | unsigned int writers; | |
ba5bb147 | 54 | unsigned int files; |
17374ff1 JA |
55 | unsigned int waiting_writers; |
56 | unsigned int r_counter; | |
57 | unsigned int w_counter; | |
35f3d14d | 58 | struct page *tmp_page; |
17374ff1 JA |
59 | struct fasync_struct *fasync_readers; |
60 | struct fasync_struct *fasync_writers; | |
35f3d14d | 61 | struct pipe_buffer *bufs; |
759c0114 | 62 | struct user_struct *user; |
17374ff1 JA |
63 | }; |
64 | ||
f84d7519 JA |
65 | /* |
66 | * Note on the nesting of these functions: | |
67 | * | |
cac36bb0 | 68 | * ->confirm() |
f84d7519 | 69 | * ->steal() |
f84d7519 | 70 | * |
a949e639 MS |
71 | * That is, ->steal() must be called on a confirmed buffer. |
72 | * See below for the meaning of each operation. Also see kerneldoc | |
73 | * in fs/pipe.c for the pipe and generic variants of these hooks. | |
f84d7519 | 74 | */ |
1da177e4 | 75 | struct pipe_buf_operations { |
0845718d JA |
76 | /* |
77 | * This is set to 1, if the generic pipe read/write may coalesce | |
78 | * data into an existing buffer. If this is set to 0, a new pipe | |
79 | * page segment is always used for new data. | |
80 | */ | |
1da177e4 | 81 | int can_merge; |
0845718d | 82 | |
0845718d JA |
83 | /* |
84 | * ->confirm() verifies that the data in the pipe buffer is there | |
85 | * and that the contents are good. If the pages in the pipe belong | |
86 | * to a file system, we may need to wait for IO completion in this | |
87 | * hook. Returns 0 for good, or a negative error value in case of | |
88 | * error. | |
89 | */ | |
cac36bb0 | 90 | int (*confirm)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
91 | |
92 | /* | |
93 | * When the contents of this pipe buffer has been completely | |
94 | * consumed by a reader, ->release() is called. | |
95 | */ | |
1da177e4 | 96 | void (*release)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
97 | |
98 | /* | |
99 | * Attempt to take ownership of the pipe buffer and its contents. | |
100 | * ->steal() returns 0 for success, in which case the contents | |
101 | * of the pipe (the buf->page) is locked and now completely owned | |
102 | * by the caller. The page may then be transferred to a different | |
103 | * mapping, the most often used case is insertion into different | |
104 | * file address space cache. | |
105 | */ | |
5abc97aa | 106 | int (*steal)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
107 | |
108 | /* | |
109 | * Get a reference to the pipe buffer. | |
110 | */ | |
9254e546 | 111 | bool (*get)(struct pipe_inode_info *, struct pipe_buffer *); |
1da177e4 LT |
112 | }; |
113 | ||
7bf2d1df MS |
114 | /** |
115 | * pipe_buf_get - get a reference to a pipe_buffer | |
116 | * @pipe: the pipe that the buffer belongs to | |
117 | * @buf: the buffer to get a reference to | |
9254e546 MW |
118 | * |
119 | * Return: %true if the reference was successfully obtained. | |
7bf2d1df | 120 | */ |
9254e546 | 121 | static inline __must_check bool pipe_buf_get(struct pipe_inode_info *pipe, |
7bf2d1df MS |
122 | struct pipe_buffer *buf) |
123 | { | |
9254e546 | 124 | return buf->ops->get(pipe, buf); |
7bf2d1df MS |
125 | } |
126 | ||
a779638c MS |
127 | /** |
128 | * pipe_buf_release - put a reference to a pipe_buffer | |
129 | * @pipe: the pipe that the buffer belongs to | |
130 | * @buf: the buffer to put a reference to | |
131 | */ | |
132 | static inline void pipe_buf_release(struct pipe_inode_info *pipe, | |
133 | struct pipe_buffer *buf) | |
134 | { | |
135 | const struct pipe_buf_operations *ops = buf->ops; | |
136 | ||
137 | buf->ops = NULL; | |
138 | ops->release(pipe, buf); | |
139 | } | |
140 | ||
fba597db MS |
141 | /** |
142 | * pipe_buf_confirm - verify contents of the pipe buffer | |
143 | * @pipe: the pipe that the buffer belongs to | |
144 | * @buf: the buffer to confirm | |
145 | */ | |
146 | static inline int pipe_buf_confirm(struct pipe_inode_info *pipe, | |
147 | struct pipe_buffer *buf) | |
148 | { | |
149 | return buf->ops->confirm(pipe, buf); | |
150 | } | |
151 | ||
ca76f5b6 MS |
152 | /** |
153 | * pipe_buf_steal - attempt to take ownership of a pipe_buffer | |
154 | * @pipe: the pipe that the buffer belongs to | |
155 | * @buf: the buffer to attempt to steal | |
156 | */ | |
157 | static inline int pipe_buf_steal(struct pipe_inode_info *pipe, | |
158 | struct pipe_buffer *buf) | |
159 | { | |
160 | return buf->ops->steal(pipe, buf); | |
161 | } | |
162 | ||
1da177e4 LT |
163 | /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual |
164 | memory allocation, whereas PIPE_BUF makes atomicity guarantees. */ | |
165 | #define PIPE_SIZE PAGE_SIZE | |
166 | ||
61e0d47c MS |
167 | /* Pipe lock and unlock operations */ |
168 | void pipe_lock(struct pipe_inode_info *); | |
169 | void pipe_unlock(struct pipe_inode_info *); | |
170 | void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *); | |
171 | ||
ff9da691 | 172 | extern unsigned int pipe_max_size, pipe_min_size; |
759c0114 WT |
173 | extern unsigned long pipe_user_pages_hard; |
174 | extern unsigned long pipe_user_pages_soft; | |
ff9da691 JA |
175 | int pipe_proc_fn(struct ctl_table *, int, void __user *, size_t *, loff_t *); |
176 | ||
1da177e4 | 177 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
3a326a2c | 178 | void pipe_wait(struct pipe_inode_info *pipe); |
1da177e4 | 179 | |
7bee130e | 180 | struct pipe_inode_info *alloc_pipe_info(void); |
4b8a8f1e | 181 | void free_pipe_info(struct pipe_inode_info *); |
1da177e4 | 182 | |
f84d7519 | 183 | /* Generic pipe buffer ops functions */ |
9254e546 | 184 | bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *); |
cac36bb0 | 185 | int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *); |
330ab716 | 186 | int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *); |
b32f00d8 | 187 | int generic_pipe_buf_nosteal(struct pipe_inode_info *, struct pipe_buffer *); |
6818173b | 188 | void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *); |
56f53954 | 189 | void pipe_buf_mark_unmergeable(struct pipe_buffer *buf); |
f84d7519 | 190 | |
28a625cb MS |
191 | extern const struct pipe_buf_operations nosteal_pipe_buf_ops; |
192 | ||
35f3d14d JA |
193 | /* for F_SETPIPE_SZ and F_GETPIPE_SZ */ |
194 | long pipe_fcntl(struct file *, unsigned int, unsigned long arg); | |
72083646 | 195 | struct pipe_inode_info *get_pipe_info(struct file *file); |
c66fb347 | 196 | |
e4fad8e5 | 197 | int create_pipe_files(struct file **, int); |
7a8d1819 | 198 | unsigned int round_pipe_size(unsigned int size); |
e4fad8e5 | 199 | |
1da177e4 | 200 | #endif |