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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 */ |
f6dd9755 | 11 | #define PIPE_BUF_FLAG_CAN_MERGE 0x10 /* can merge buffers */ |
6c329784 | 12 | #define PIPE_BUF_FLAG_WHOLE 0x20 /* read() must return entire buffer or error */ |
e7d553d6 | 13 | #ifdef CONFIG_WATCH_QUEUE |
6c329784 | 14 | #define PIPE_BUF_FLAG_LOSS 0x40 /* Message loss happened after this buffer */ |
e7d553d6 | 15 | #endif |
3e7ee3e7 | 16 | |
0845718d JA |
17 | /** |
18 | * struct pipe_buffer - a linux kernel pipe buffer | |
19 | * @page: the page containing the data for the pipe buffer | |
20 | * @offset: offset of data inside the @page | |
21 | * @len: length of data inside the @page | |
22 | * @ops: operations associated with this buffer. See @pipe_buf_operations. | |
23 | * @flags: pipe buffer flags. See above. | |
24 | * @private: private data owned by the ops. | |
25 | **/ | |
1da177e4 LT |
26 | struct pipe_buffer { |
27 | struct page *page; | |
28 | unsigned int offset, len; | |
d4c3cca9 | 29 | const struct pipe_buf_operations *ops; |
3e7ee3e7 | 30 | unsigned int flags; |
497f9625 | 31 | unsigned long private; |
1da177e4 LT |
32 | }; |
33 | ||
0845718d JA |
34 | /** |
35 | * struct pipe_inode_info - a linux kernel pipe | |
72b0d9aa | 36 | * @mutex: mutex protecting the whole thing |
0bf999f9 RD |
37 | * @rd_wait: reader wait point in case of empty pipe |
38 | * @wr_wait: writer wait point in case of full pipe | |
8cefc107 DH |
39 | * @head: The point of buffer production |
40 | * @tail: The point of buffer consumption | |
e7d553d6 | 41 | * @note_loss: The next read() should insert a data-lost message |
6718b6f8 | 42 | * @max_usage: The maximum number of slots that may be used in the ring |
8cefc107 | 43 | * @ring_size: total number of buffers (should be a power of 2) |
c73be61c | 44 | * @nr_accounted: The amount this pipe accounts for in user->pipe_bufs |
0845718d JA |
45 | * @tmp_page: cached released page |
46 | * @readers: number of current readers of this pipe | |
47 | * @writers: number of current writers of this pipe | |
e227867f | 48 | * @files: number of struct file referring this pipe (protected by ->i_lock) |
0845718d JA |
49 | * @r_counter: reader counter |
50 | * @w_counter: writer counter | |
3b844826 | 51 | * @poll_usage: is this pipe used for epoll, which has crazy wakeups? |
0845718d JA |
52 | * @fasync_readers: reader side fasync |
53 | * @fasync_writers: writer side fasync | |
0845718d | 54 | * @bufs: the circular array of pipe buffers |
759c0114 | 55 | * @user: the user who created this pipe |
c73be61c | 56 | * @watch_queue: If this pipe is a watch_queue, this is the stuff for that |
0845718d | 57 | **/ |
17374ff1 | 58 | struct pipe_inode_info { |
72b0d9aa | 59 | struct mutex mutex; |
0ddad21d | 60 | wait_queue_head_t rd_wait, wr_wait; |
8cefc107 DH |
61 | unsigned int head; |
62 | unsigned int tail; | |
6718b6f8 | 63 | unsigned int max_usage; |
8cefc107 | 64 | unsigned int ring_size; |
e7d553d6 DH |
65 | #ifdef CONFIG_WATCH_QUEUE |
66 | bool note_loss; | |
67 | #endif | |
c73be61c | 68 | unsigned int nr_accounted; |
17374ff1 JA |
69 | unsigned int readers; |
70 | unsigned int writers; | |
ba5bb147 | 71 | unsigned int files; |
17374ff1 JA |
72 | unsigned int r_counter; |
73 | unsigned int w_counter; | |
f485922d | 74 | bool poll_usage; |
35f3d14d | 75 | struct page *tmp_page; |
17374ff1 JA |
76 | struct fasync_struct *fasync_readers; |
77 | struct fasync_struct *fasync_writers; | |
35f3d14d | 78 | struct pipe_buffer *bufs; |
759c0114 | 79 | struct user_struct *user; |
c73be61c DH |
80 | #ifdef CONFIG_WATCH_QUEUE |
81 | struct watch_queue *watch_queue; | |
82 | #endif | |
17374ff1 JA |
83 | }; |
84 | ||
f84d7519 JA |
85 | /* |
86 | * Note on the nesting of these functions: | |
87 | * | |
cac36bb0 | 88 | * ->confirm() |
c928f642 | 89 | * ->try_steal() |
f84d7519 | 90 | * |
c928f642 CH |
91 | * That is, ->try_steal() must be called on a confirmed buffer. See below for |
92 | * the meaning of each operation. Also see the kerneldoc in fs/pipe.c for the | |
93 | * pipe and generic variants of these hooks. | |
f84d7519 | 94 | */ |
1da177e4 | 95 | struct pipe_buf_operations { |
0845718d JA |
96 | /* |
97 | * ->confirm() verifies that the data in the pipe buffer is there | |
98 | * and that the contents are good. If the pages in the pipe belong | |
99 | * to a file system, we may need to wait for IO completion in this | |
100 | * hook. Returns 0 for good, or a negative error value in case of | |
b8d9e7f2 | 101 | * error. If not present all pages are considered good. |
0845718d | 102 | */ |
cac36bb0 | 103 | int (*confirm)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
104 | |
105 | /* | |
106 | * When the contents of this pipe buffer has been completely | |
107 | * consumed by a reader, ->release() is called. | |
108 | */ | |
1da177e4 | 109 | void (*release)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
110 | |
111 | /* | |
112 | * Attempt to take ownership of the pipe buffer and its contents. | |
c928f642 CH |
113 | * ->try_steal() returns %true for success, in which case the contents |
114 | * of the pipe (the buf->page) is locked and now completely owned by the | |
115 | * caller. The page may then be transferred to a different mapping, the | |
116 | * most often used case is insertion into different file address space | |
117 | * cache. | |
0845718d | 118 | */ |
c928f642 | 119 | bool (*try_steal)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
120 | |
121 | /* | |
122 | * Get a reference to the pipe buffer. | |
123 | */ | |
15fab63e | 124 | bool (*get)(struct pipe_inode_info *, struct pipe_buffer *); |
1da177e4 LT |
125 | }; |
126 | ||
8cefc107 DH |
127 | /** |
128 | * pipe_empty - Return true if the pipe is empty | |
129 | * @head: The pipe ring head pointer | |
130 | * @tail: The pipe ring tail pointer | |
131 | */ | |
132 | static inline bool pipe_empty(unsigned int head, unsigned int tail) | |
133 | { | |
134 | return head == tail; | |
135 | } | |
136 | ||
137 | /** | |
138 | * pipe_occupancy - Return number of slots used in the pipe | |
139 | * @head: The pipe ring head pointer | |
140 | * @tail: The pipe ring tail pointer | |
141 | */ | |
142 | static inline unsigned int pipe_occupancy(unsigned int head, unsigned int tail) | |
143 | { | |
144 | return head - tail; | |
145 | } | |
146 | ||
147 | /** | |
148 | * pipe_full - Return true if the pipe is full | |
149 | * @head: The pipe ring head pointer | |
150 | * @tail: The pipe ring tail pointer | |
151 | * @limit: The maximum amount of slots available. | |
152 | */ | |
153 | static inline bool pipe_full(unsigned int head, unsigned int tail, | |
154 | unsigned int limit) | |
155 | { | |
156 | return pipe_occupancy(head, tail) >= limit; | |
157 | } | |
158 | ||
7bf2d1df MS |
159 | /** |
160 | * pipe_buf_get - get a reference to a pipe_buffer | |
161 | * @pipe: the pipe that the buffer belongs to | |
162 | * @buf: the buffer to get a reference to | |
15fab63e MW |
163 | * |
164 | * Return: %true if the reference was successfully obtained. | |
7bf2d1df | 165 | */ |
15fab63e | 166 | static inline __must_check bool pipe_buf_get(struct pipe_inode_info *pipe, |
7bf2d1df MS |
167 | struct pipe_buffer *buf) |
168 | { | |
15fab63e | 169 | return buf->ops->get(pipe, buf); |
7bf2d1df MS |
170 | } |
171 | ||
a779638c MS |
172 | /** |
173 | * pipe_buf_release - put a reference to a pipe_buffer | |
174 | * @pipe: the pipe that the buffer belongs to | |
175 | * @buf: the buffer to put a reference to | |
176 | */ | |
177 | static inline void pipe_buf_release(struct pipe_inode_info *pipe, | |
178 | struct pipe_buffer *buf) | |
179 | { | |
180 | const struct pipe_buf_operations *ops = buf->ops; | |
181 | ||
182 | buf->ops = NULL; | |
183 | ops->release(pipe, buf); | |
184 | } | |
185 | ||
fba597db MS |
186 | /** |
187 | * pipe_buf_confirm - verify contents of the pipe buffer | |
188 | * @pipe: the pipe that the buffer belongs to | |
189 | * @buf: the buffer to confirm | |
190 | */ | |
191 | static inline int pipe_buf_confirm(struct pipe_inode_info *pipe, | |
192 | struct pipe_buffer *buf) | |
193 | { | |
b8d9e7f2 CH |
194 | if (!buf->ops->confirm) |
195 | return 0; | |
fba597db MS |
196 | return buf->ops->confirm(pipe, buf); |
197 | } | |
198 | ||
ca76f5b6 | 199 | /** |
c928f642 | 200 | * pipe_buf_try_steal - attempt to take ownership of a pipe_buffer |
ca76f5b6 MS |
201 | * @pipe: the pipe that the buffer belongs to |
202 | * @buf: the buffer to attempt to steal | |
203 | */ | |
c928f642 CH |
204 | static inline bool pipe_buf_try_steal(struct pipe_inode_info *pipe, |
205 | struct pipe_buffer *buf) | |
ca76f5b6 | 206 | { |
c928f642 CH |
207 | if (!buf->ops->try_steal) |
208 | return false; | |
209 | return buf->ops->try_steal(pipe, buf); | |
ca76f5b6 MS |
210 | } |
211 | ||
c3497fd0 AV |
212 | static inline void pipe_discard_from(struct pipe_inode_info *pipe, |
213 | unsigned int old_head) | |
214 | { | |
215 | unsigned int mask = pipe->ring_size - 1; | |
216 | ||
217 | while (pipe->head > old_head) | |
218 | pipe_buf_release(pipe, &pipe->bufs[--pipe->head & mask]); | |
219 | } | |
220 | ||
1da177e4 LT |
221 | /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual |
222 | memory allocation, whereas PIPE_BUF makes atomicity guarantees. */ | |
223 | #define PIPE_SIZE PAGE_SIZE | |
224 | ||
61e0d47c MS |
225 | /* Pipe lock and unlock operations */ |
226 | void pipe_lock(struct pipe_inode_info *); | |
227 | void pipe_unlock(struct pipe_inode_info *); | |
228 | void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *); | |
229 | ||
472e5b05 LT |
230 | /* Wait for a pipe to be readable/writable while dropping the pipe lock */ |
231 | void pipe_wait_readable(struct pipe_inode_info *); | |
232 | void pipe_wait_writable(struct pipe_inode_info *); | |
1da177e4 | 233 | |
7bee130e | 234 | struct pipe_inode_info *alloc_pipe_info(void); |
4b8a8f1e | 235 | void free_pipe_info(struct pipe_inode_info *); |
1da177e4 | 236 | |
f84d7519 | 237 | /* Generic pipe buffer ops functions */ |
15fab63e | 238 | bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *); |
c928f642 | 239 | bool generic_pipe_buf_try_steal(struct pipe_inode_info *, struct pipe_buffer *); |
6818173b | 240 | void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *); |
f84d7519 | 241 | |
28a625cb MS |
242 | extern const struct pipe_buf_operations nosteal_pipe_buf_ops; |
243 | ||
c73be61c DH |
244 | #ifdef CONFIG_WATCH_QUEUE |
245 | unsigned long account_pipe_buffers(struct user_struct *user, | |
246 | unsigned long old, unsigned long new); | |
247 | bool too_many_pipe_buffers_soft(unsigned long user_bufs); | |
248 | bool too_many_pipe_buffers_hard(unsigned long user_bufs); | |
249 | bool pipe_is_unprivileged_user(void); | |
250 | #endif | |
251 | ||
35f3d14d | 252 | /* for F_SETPIPE_SZ and F_GETPIPE_SZ */ |
c73be61c DH |
253 | #ifdef CONFIG_WATCH_QUEUE |
254 | int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots); | |
255 | #endif | |
35f3d14d | 256 | long pipe_fcntl(struct file *, unsigned int, unsigned long arg); |
c73be61c | 257 | struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice); |
c66fb347 | 258 | |
e4fad8e5 | 259 | int create_pipe_files(struct file **, int); |
96e99be4 | 260 | unsigned int round_pipe_size(unsigned long size); |
e4fad8e5 | 261 | |
1da177e4 | 262 | #endif |