1 #ifndef _LINUX_PIPE_FS_I_H 2 #define _LINUX_PIPE_FS_I_H 3 4 #define PIPEFS_MAGIC 0x50495045 5 6 #define PIPE_BUFFERS (16) 7 8 #define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */ 9 #define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */ 10 #define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */ 11 12 struct pipe_buffer { 13 struct page *page; 14 unsigned int offset, len; 15 const struct pipe_buf_operations *ops; 16 unsigned int flags; 17 }; 18 19 /* 20 * Note on the nesting of these functions: 21 * 22 * ->pin() 23 * ->steal() 24 * ... 25 * ->map() 26 * ... 27 * ->unmap() 28 * 29 * That is, ->map() must be called on a pinned buffer, same goes for ->steal(). 30 */ 31 struct pipe_buf_operations { 32 int can_merge; 33 void * (*map)(struct pipe_inode_info *, struct pipe_buffer *, int); 34 void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *, void *); 35 int (*pin)(struct pipe_inode_info *, struct pipe_buffer *); 36 void (*release)(struct pipe_inode_info *, struct pipe_buffer *); 37 int (*steal)(struct pipe_inode_info *, struct pipe_buffer *); 38 void (*get)(struct pipe_inode_info *, struct pipe_buffer *); 39 }; 40 41 struct pipe_inode_info { 42 wait_queue_head_t wait; 43 unsigned int nrbufs, curbuf; 44 struct page *tmp_page; 45 unsigned int readers; 46 unsigned int writers; 47 unsigned int waiting_writers; 48 unsigned int r_counter; 49 unsigned int w_counter; 50 struct fasync_struct *fasync_readers; 51 struct fasync_struct *fasync_writers; 52 struct inode *inode; 53 struct pipe_buffer bufs[PIPE_BUFFERS]; 54 }; 55 56 /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual 57 memory allocation, whereas PIPE_BUF makes atomicity guarantees. */ 58 #define PIPE_SIZE PAGE_SIZE 59 60 /* Drop the inode semaphore and wait for a pipe event, atomically */ 61 void pipe_wait(struct pipe_inode_info *pipe); 62 63 struct pipe_inode_info * alloc_pipe_info(struct inode * inode); 64 void free_pipe_info(struct inode * inode); 65 void __free_pipe_info(struct pipe_inode_info *); 66 67 /* Generic pipe buffer ops functions */ 68 void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *, int); 69 void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *, void *); 70 void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *); 71 int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *); 72 int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *); 73 74 /* 75 * splice is tied to pipes as a transport (at least for now), so we'll just 76 * add the splice flags here. 77 */ 78 #define SPLICE_F_MOVE (0x01) /* move pages instead of copying */ 79 #define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */ 80 /* we may still block on the fd we splice */ 81 /* from/to, of course */ 82 #define SPLICE_F_MORE (0x04) /* expect more data */ 83 #define SPLICE_F_GIFT (0x08) /* pages passed in are a gift */ 84 85 /* 86 * Passed to the actors 87 */ 88 struct splice_desc { 89 unsigned int len, total_len; /* current and remaining length */ 90 unsigned int flags; /* splice flags */ 91 struct file *file; /* file to read/write */ 92 loff_t pos; /* file position */ 93 }; 94 95 typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *, 96 struct splice_desc *); 97 98 extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *, 99 loff_t *, size_t, unsigned int, 100 splice_actor *); 101 102 extern ssize_t __splice_from_pipe(struct pipe_inode_info *, struct file *, 103 loff_t *, size_t, unsigned int, 104 splice_actor *); 105 106 #endif 107