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1da177e4 LT |
1 | #ifndef _LINUX_PIPE_FS_I_H |
2 | #define _LINUX_PIPE_FS_I_H | |
3 | ||
35f3d14d | 4 | #define PIPE_DEF_BUFFERS 16 |
1da177e4 | 5 | |
1432873a JA |
6 | #define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */ |
7 | #define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */ | |
8 | #define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */ | |
9883035a | 9 | #define PIPE_BUF_FLAG_PACKET 0x08 /* read() as a packet */ |
3e7ee3e7 | 10 | |
0845718d JA |
11 | /** |
12 | * struct pipe_buffer - a linux kernel pipe buffer | |
13 | * @page: the page containing the data for the pipe buffer | |
14 | * @offset: offset of data inside the @page | |
15 | * @len: length of data inside the @page | |
16 | * @ops: operations associated with this buffer. See @pipe_buf_operations. | |
17 | * @flags: pipe buffer flags. See above. | |
18 | * @private: private data owned by the ops. | |
19 | **/ | |
1da177e4 LT |
20 | struct pipe_buffer { |
21 | struct page *page; | |
22 | unsigned int offset, len; | |
d4c3cca9 | 23 | const struct pipe_buf_operations *ops; |
3e7ee3e7 | 24 | unsigned int flags; |
497f9625 | 25 | unsigned long private; |
1da177e4 LT |
26 | }; |
27 | ||
0845718d JA |
28 | /** |
29 | * struct pipe_inode_info - a linux kernel pipe | |
30 | * @wait: reader/writer wait point in case of empty/full pipe | |
31 | * @nrbufs: the number of non-empty pipe buffers in this pipe | |
0dc14885 | 32 | * @buffers: total number of buffers (should be a power of 2) |
0845718d JA |
33 | * @curbuf: the current pipe buffer entry |
34 | * @tmp_page: cached released page | |
35 | * @readers: number of current readers of this pipe | |
36 | * @writers: number of current writers of this pipe | |
37 | * @waiting_writers: number of writers blocked waiting for room | |
38 | * @r_counter: reader counter | |
39 | * @w_counter: writer counter | |
40 | * @fasync_readers: reader side fasync | |
41 | * @fasync_writers: writer side fasync | |
42 | * @inode: inode this pipe is attached to | |
43 | * @bufs: the circular array of pipe buffers | |
44 | **/ | |
17374ff1 JA |
45 | struct pipe_inode_info { |
46 | wait_queue_head_t wait; | |
35f3d14d | 47 | unsigned int nrbufs, curbuf, buffers; |
17374ff1 JA |
48 | unsigned int readers; |
49 | unsigned int writers; | |
50 | unsigned int waiting_writers; | |
51 | unsigned int r_counter; | |
52 | unsigned int w_counter; | |
35f3d14d | 53 | struct page *tmp_page; |
17374ff1 JA |
54 | struct fasync_struct *fasync_readers; |
55 | struct fasync_struct *fasync_writers; | |
56 | struct inode *inode; | |
35f3d14d | 57 | struct pipe_buffer *bufs; |
17374ff1 JA |
58 | }; |
59 | ||
f84d7519 JA |
60 | /* |
61 | * Note on the nesting of these functions: | |
62 | * | |
cac36bb0 | 63 | * ->confirm() |
f84d7519 JA |
64 | * ->steal() |
65 | * ... | |
66 | * ->map() | |
67 | * ... | |
68 | * ->unmap() | |
69 | * | |
cac36bb0 | 70 | * That is, ->map() must be called on a confirmed buffer, |
0845718d JA |
71 | * same goes for ->steal(). See below for the meaning of each |
72 | * operation. Also see kerneldoc in fs/pipe.c for the pipe | |
73 | * 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 JA |
82 | |
83 | /* | |
84 | * ->map() returns a virtual address mapping of the pipe buffer. | |
85 | * The last integer flag reflects whether this should be an atomic | |
86 | * mapping or not. The atomic map is faster, however you can't take | |
87 | * page faults before calling ->unmap() again. So if you need to eg | |
88 | * access user data through copy_to/from_user(), then you must get | |
2164d334 CW |
89 | * a non-atomic map. ->map() uses the kmap_atomic slot for |
90 | * atomic maps, you have to be careful if mapping another page as | |
91 | * source or destination for a copy. | |
0845718d | 92 | */ |
f6762b7a | 93 | void * (*map)(struct pipe_inode_info *, struct pipe_buffer *, int); |
0845718d JA |
94 | |
95 | /* | |
96 | * Undoes ->map(), finishes the virtual mapping of the pipe buffer. | |
97 | */ | |
f6762b7a | 98 | void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *, void *); |
0845718d JA |
99 | |
100 | /* | |
101 | * ->confirm() verifies that the data in the pipe buffer is there | |
102 | * and that the contents are good. If the pages in the pipe belong | |
103 | * to a file system, we may need to wait for IO completion in this | |
104 | * hook. Returns 0 for good, or a negative error value in case of | |
105 | * error. | |
106 | */ | |
cac36bb0 | 107 | int (*confirm)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
108 | |
109 | /* | |
110 | * When the contents of this pipe buffer has been completely | |
111 | * consumed by a reader, ->release() is called. | |
112 | */ | |
1da177e4 | 113 | void (*release)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
114 | |
115 | /* | |
116 | * Attempt to take ownership of the pipe buffer and its contents. | |
117 | * ->steal() returns 0 for success, in which case the contents | |
118 | * of the pipe (the buf->page) is locked and now completely owned | |
119 | * by the caller. The page may then be transferred to a different | |
120 | * mapping, the most often used case is insertion into different | |
121 | * file address space cache. | |
122 | */ | |
5abc97aa | 123 | int (*steal)(struct pipe_inode_info *, struct pipe_buffer *); |
0845718d JA |
124 | |
125 | /* | |
126 | * Get a reference to the pipe buffer. | |
127 | */ | |
70524490 | 128 | void (*get)(struct pipe_inode_info *, struct pipe_buffer *); |
1da177e4 LT |
129 | }; |
130 | ||
1da177e4 LT |
131 | /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual |
132 | memory allocation, whereas PIPE_BUF makes atomicity guarantees. */ | |
133 | #define PIPE_SIZE PAGE_SIZE | |
134 | ||
61e0d47c MS |
135 | /* Pipe lock and unlock operations */ |
136 | void pipe_lock(struct pipe_inode_info *); | |
137 | void pipe_unlock(struct pipe_inode_info *); | |
138 | void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *); | |
139 | ||
ff9da691 JA |
140 | extern unsigned int pipe_max_size, pipe_min_size; |
141 | int pipe_proc_fn(struct ctl_table *, int, void __user *, size_t *, loff_t *); | |
142 | ||
b492e95b | 143 | |
1da177e4 | 144 | /* Drop the inode semaphore and wait for a pipe event, atomically */ |
3a326a2c | 145 | void pipe_wait(struct pipe_inode_info *pipe); |
1da177e4 | 146 | |
3a326a2c IM |
147 | struct pipe_inode_info * alloc_pipe_info(struct inode * inode); |
148 | void free_pipe_info(struct inode * inode); | |
b92ce558 | 149 | void __free_pipe_info(struct pipe_inode_info *); |
1da177e4 | 150 | |
f84d7519 | 151 | /* Generic pipe buffer ops functions */ |
f6762b7a JA |
152 | void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *, int); |
153 | void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *, void *); | |
f84d7519 | 154 | void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *); |
cac36bb0 | 155 | int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *); |
330ab716 | 156 | int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *); |
6818173b | 157 | void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *); |
f84d7519 | 158 | |
35f3d14d JA |
159 | /* for F_SETPIPE_SZ and F_GETPIPE_SZ */ |
160 | long pipe_fcntl(struct file *, unsigned int, unsigned long arg); | |
72083646 | 161 | struct pipe_inode_info *get_pipe_info(struct file *file); |
c66fb347 | 162 | |
e4fad8e5 AV |
163 | int create_pipe_files(struct file **, int); |
164 | ||
1da177e4 | 165 | #endif |