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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 |
0bf999f9 RD |
32 | * @rd_wait: reader wait point in case of empty pipe |
33 | * @wr_wait: writer wait point in case of full pipe | |
8cefc107 DH |
34 | * @head: The point of buffer production |
35 | * @tail: The point of buffer consumption | |
6718b6f8 | 36 | * @max_usage: The maximum number of slots that may be used in the ring |
8cefc107 | 37 | * @ring_size: total number of buffers (should be a power of 2) |
c73be61c | 38 | * @nr_accounted: The amount this pipe accounts for in user->pipe_bufs |
0845718d JA |
39 | * @tmp_page: cached released page |
40 | * @readers: number of current readers of this pipe | |
41 | * @writers: number of current writers of this pipe | |
e227867f | 42 | * @files: number of struct file referring this pipe (protected by ->i_lock) |
0845718d JA |
43 | * @r_counter: reader counter |
44 | * @w_counter: writer counter | |
45 | * @fasync_readers: reader side fasync | |
46 | * @fasync_writers: writer side fasync | |
0845718d | 47 | * @bufs: the circular array of pipe buffers |
759c0114 | 48 | * @user: the user who created this pipe |
c73be61c | 49 | * @watch_queue: If this pipe is a watch_queue, this is the stuff for that |
0845718d | 50 | **/ |
17374ff1 | 51 | struct pipe_inode_info { |
72b0d9aa | 52 | struct mutex mutex; |
0ddad21d | 53 | wait_queue_head_t rd_wait, wr_wait; |
8cefc107 DH |
54 | unsigned int head; |
55 | unsigned int tail; | |
6718b6f8 | 56 | unsigned int max_usage; |
8cefc107 | 57 | unsigned int ring_size; |
c73be61c | 58 | unsigned int nr_accounted; |
17374ff1 JA |
59 | unsigned int readers; |
60 | unsigned int writers; | |
ba5bb147 | 61 | unsigned int files; |
17374ff1 JA |
62 | unsigned int r_counter; |
63 | unsigned int w_counter; | |
35f3d14d | 64 | struct page *tmp_page; |
17374ff1 JA |
65 | struct fasync_struct *fasync_readers; |
66 | struct fasync_struct *fasync_writers; | |
35f3d14d | 67 | struct pipe_buffer *bufs; |
759c0114 | 68 | struct user_struct *user; |
c73be61c DH |
69 | #ifdef CONFIG_WATCH_QUEUE |
70 | struct watch_queue *watch_queue; | |
71 | #endif | |
17374ff1 JA |
72 | }; |
73 | ||
f84d7519 JA |
74 | /* |
75 | * Note on the nesting of these functions: | |
76 | * | |
cac36bb0 | 77 | * ->confirm() |
f84d7519 | 78 | * ->steal() |
f84d7519 | 79 | * |
a949e639 MS |
80 | * That is, ->steal() must be called on a confirmed buffer. |
81 | * See below for the meaning of each operation. Also see kerneldoc | |
82 | * in fs/pipe.c for the pipe and generic variants of these hooks. | |
f84d7519 | 83 | */ |
1da177e4 | 84 | struct pipe_buf_operations { |
0845718d JA |
85 | /* |
86 | * ->confirm() verifies that the data in the pipe buffer is there | |
87 | * and that the contents are good. If the pages in the pipe belong | |
88 | * to a file system, we may need to wait for IO completion in this | |
89 | * hook. Returns 0 for good, or a negative error value in case of | |
90 | * error. | |
91 | */ | |
cac36bb0 | 92 | int (*confirm)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
93 | |
94 | /* | |
95 | * When the contents of this pipe buffer has been completely | |
96 | * consumed by a reader, ->release() is called. | |
97 | */ | |
1da177e4 | 98 | void (*release)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
99 | |
100 | /* | |
101 | * Attempt to take ownership of the pipe buffer and its contents. | |
102 | * ->steal() returns 0 for success, in which case the contents | |
103 | * of the pipe (the buf->page) is locked and now completely owned | |
104 | * by the caller. The page may then be transferred to a different | |
105 | * mapping, the most often used case is insertion into different | |
106 | * file address space cache. | |
107 | */ | |
5abc97aa | 108 | int (*steal)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
109 | |
110 | /* | |
111 | * Get a reference to the pipe buffer. | |
112 | */ | |
15fab63e | 113 | bool (*get)(struct pipe_inode_info *, struct pipe_buffer *); |
1da177e4 LT |
114 | }; |
115 | ||
8cefc107 DH |
116 | /** |
117 | * pipe_empty - Return true if the pipe is empty | |
118 | * @head: The pipe ring head pointer | |
119 | * @tail: The pipe ring tail pointer | |
120 | */ | |
121 | static inline bool pipe_empty(unsigned int head, unsigned int tail) | |
122 | { | |
123 | return head == tail; | |
124 | } | |
125 | ||
126 | /** | |
127 | * pipe_occupancy - Return number of slots used in the pipe | |
128 | * @head: The pipe ring head pointer | |
129 | * @tail: The pipe ring tail pointer | |
130 | */ | |
131 | static inline unsigned int pipe_occupancy(unsigned int head, unsigned int tail) | |
132 | { | |
133 | return head - tail; | |
134 | } | |
135 | ||
136 | /** | |
137 | * pipe_full - Return true if the pipe is full | |
138 | * @head: The pipe ring head pointer | |
139 | * @tail: The pipe ring tail pointer | |
140 | * @limit: The maximum amount of slots available. | |
141 | */ | |
142 | static inline bool pipe_full(unsigned int head, unsigned int tail, | |
143 | unsigned int limit) | |
144 | { | |
145 | return pipe_occupancy(head, tail) >= limit; | |
146 | } | |
147 | ||
148 | /** | |
149 | * pipe_space_for_user - Return number of slots available to userspace | |
150 | * @head: The pipe ring head pointer | |
151 | * @tail: The pipe ring tail pointer | |
152 | * @pipe: The pipe info structure | |
153 | */ | |
154 | static inline unsigned int pipe_space_for_user(unsigned int head, unsigned int tail, | |
155 | struct pipe_inode_info *pipe) | |
156 | { | |
157 | unsigned int p_occupancy, p_space; | |
158 | ||
159 | p_occupancy = pipe_occupancy(head, tail); | |
6718b6f8 | 160 | if (p_occupancy >= pipe->max_usage) |
8cefc107 DH |
161 | return 0; |
162 | p_space = pipe->ring_size - p_occupancy; | |
6718b6f8 DH |
163 | if (p_space > pipe->max_usage) |
164 | p_space = pipe->max_usage; | |
8cefc107 DH |
165 | return p_space; |
166 | } | |
167 | ||
7bf2d1df MS |
168 | /** |
169 | * pipe_buf_get - get a reference to a pipe_buffer | |
170 | * @pipe: the pipe that the buffer belongs to | |
171 | * @buf: the buffer to get a reference to | |
15fab63e MW |
172 | * |
173 | * Return: %true if the reference was successfully obtained. | |
7bf2d1df | 174 | */ |
15fab63e | 175 | static inline __must_check bool pipe_buf_get(struct pipe_inode_info *pipe, |
7bf2d1df MS |
176 | struct pipe_buffer *buf) |
177 | { | |
15fab63e | 178 | return buf->ops->get(pipe, buf); |
7bf2d1df MS |
179 | } |
180 | ||
a779638c MS |
181 | /** |
182 | * pipe_buf_release - put a reference to a pipe_buffer | |
183 | * @pipe: the pipe that the buffer belongs to | |
184 | * @buf: the buffer to put a reference to | |
185 | */ | |
186 | static inline void pipe_buf_release(struct pipe_inode_info *pipe, | |
187 | struct pipe_buffer *buf) | |
188 | { | |
189 | const struct pipe_buf_operations *ops = buf->ops; | |
190 | ||
191 | buf->ops = NULL; | |
192 | ops->release(pipe, buf); | |
193 | } | |
194 | ||
fba597db MS |
195 | /** |
196 | * pipe_buf_confirm - verify contents of the pipe buffer | |
197 | * @pipe: the pipe that the buffer belongs to | |
198 | * @buf: the buffer to confirm | |
199 | */ | |
200 | static inline int pipe_buf_confirm(struct pipe_inode_info *pipe, | |
201 | struct pipe_buffer *buf) | |
202 | { | |
203 | return buf->ops->confirm(pipe, buf); | |
204 | } | |
205 | ||
ca76f5b6 MS |
206 | /** |
207 | * pipe_buf_steal - attempt to take ownership of a pipe_buffer | |
208 | * @pipe: the pipe that the buffer belongs to | |
209 | * @buf: the buffer to attempt to steal | |
210 | */ | |
211 | static inline int pipe_buf_steal(struct pipe_inode_info *pipe, | |
212 | struct pipe_buffer *buf) | |
213 | { | |
214 | return buf->ops->steal(pipe, buf); | |
215 | } | |
216 | ||
1da177e4 LT |
217 | /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual |
218 | memory allocation, whereas PIPE_BUF makes atomicity guarantees. */ | |
219 | #define PIPE_SIZE PAGE_SIZE | |
220 | ||
61e0d47c MS |
221 | /* Pipe lock and unlock operations */ |
222 | void pipe_lock(struct pipe_inode_info *); | |
223 | void pipe_unlock(struct pipe_inode_info *); | |
224 | void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *); | |
225 | ||
4c2e4bef | 226 | extern unsigned int pipe_max_size; |
759c0114 WT |
227 | extern unsigned long pipe_user_pages_hard; |
228 | extern unsigned long pipe_user_pages_soft; | |
ff9da691 | 229 | |
1da177e4 | 230 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
3a326a2c | 231 | void pipe_wait(struct pipe_inode_info *pipe); |
1da177e4 | 232 | |
7bee130e | 233 | struct pipe_inode_info *alloc_pipe_info(void); |
4b8a8f1e | 234 | void free_pipe_info(struct pipe_inode_info *); |
1da177e4 | 235 | |
f84d7519 | 236 | /* Generic pipe buffer ops functions */ |
15fab63e | 237 | bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *); |
cac36bb0 | 238 | int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *); |
330ab716 | 239 | int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *); |
b9872226 | 240 | int generic_pipe_buf_nosteal(struct pipe_inode_info *, struct pipe_buffer *); |
6818173b | 241 | void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *); |
a0ce2f0a | 242 | void pipe_buf_mark_unmergeable(struct pipe_buffer *buf); |
f84d7519 | 243 | |
28a625cb MS |
244 | extern const struct pipe_buf_operations nosteal_pipe_buf_ops; |
245 | ||
c73be61c DH |
246 | #ifdef CONFIG_WATCH_QUEUE |
247 | unsigned long account_pipe_buffers(struct user_struct *user, | |
248 | unsigned long old, unsigned long new); | |
249 | bool too_many_pipe_buffers_soft(unsigned long user_bufs); | |
250 | bool too_many_pipe_buffers_hard(unsigned long user_bufs); | |
251 | bool pipe_is_unprivileged_user(void); | |
252 | #endif | |
253 | ||
35f3d14d | 254 | /* for F_SETPIPE_SZ and F_GETPIPE_SZ */ |
c73be61c DH |
255 | #ifdef CONFIG_WATCH_QUEUE |
256 | int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots); | |
257 | #endif | |
35f3d14d | 258 | long pipe_fcntl(struct file *, unsigned int, unsigned long arg); |
c73be61c | 259 | struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice); |
c66fb347 | 260 | |
e4fad8e5 | 261 | int create_pipe_files(struct file **, int); |
96e99be4 | 262 | unsigned int round_pipe_size(unsigned long size); |
e4fad8e5 | 263 | |
1da177e4 | 264 | #endif |