3a326a2ce8
separate out the 'internal pipe object' abstraction, and make it usable to splice. This cleans up and fixes several aspects of the internal splice APIs and the pipe code: - pipes: the allocation and freeing of pipe_inode_info is now more symmetric and more streamlined with existing kernel practices. - splice: small micro-optimization: less pointer dereferencing in splice methods Signed-off-by: Ingo Molnar <mingo@elte.hu> Update XFS for the ->splice_read/->splice_write changes. Signed-off-by: Jens Axboe <axboe@suse.de>
73 lines
2.3 KiB
C
73 lines
2.3 KiB
C
#ifndef _LINUX_PIPE_FS_I_H
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#define _LINUX_PIPE_FS_I_H
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#define PIPEFS_MAGIC 0x50495045
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#define PIPE_BUFFERS (16)
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#define PIPE_BUF_FLAG_STOLEN 0x01
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#define PIPE_BUF_FLAG_LRU 0x02
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struct pipe_buffer {
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struct page *page;
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unsigned int offset, len;
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struct pipe_buf_operations *ops;
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unsigned int flags;
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};
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struct pipe_buf_operations {
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int can_merge;
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void * (*map)(struct file *, struct pipe_inode_info *, struct pipe_buffer *);
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void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *);
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void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
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int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
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};
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struct pipe_inode_info {
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wait_queue_head_t wait;
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unsigned int nrbufs, curbuf;
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struct pipe_buffer bufs[PIPE_BUFFERS];
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struct page *tmp_page;
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unsigned int start;
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unsigned int readers;
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unsigned int writers;
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unsigned int waiting_writers;
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unsigned int r_counter;
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unsigned int w_counter;
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struct fasync_struct *fasync_readers;
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struct fasync_struct *fasync_writers;
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struct inode *inode;
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};
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/* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
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memory allocation, whereas PIPE_BUF makes atomicity guarantees. */
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#define PIPE_SIZE PAGE_SIZE
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#define PIPE_MUTEX(inode) (&(inode).i_mutex)
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#define PIPE_WAIT(inode) (&(inode).i_pipe->wait)
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#define PIPE_READERS(inode) ((inode).i_pipe->readers)
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#define PIPE_WRITERS(inode) ((inode).i_pipe->writers)
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#define PIPE_WAITING_WRITERS(inode) ((inode).i_pipe->waiting_writers)
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#define PIPE_RCOUNTER(inode) ((inode).i_pipe->r_counter)
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#define PIPE_WCOUNTER(inode) ((inode).i_pipe->w_counter)
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#define PIPE_FASYNC_READERS(inode) (&((inode).i_pipe->fasync_readers))
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#define PIPE_FASYNC_WRITERS(inode) (&((inode).i_pipe->fasync_writers))
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/* Drop the inode semaphore and wait for a pipe event, atomically */
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void pipe_wait(struct pipe_inode_info *pipe);
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struct pipe_inode_info * alloc_pipe_info(struct inode * inode);
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void free_pipe_info(struct inode * inode);
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/*
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* splice is tied to pipes as a transport (at least for now), so we'll just
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* add the splice flags here.
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*/
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#define SPLICE_F_MOVE (0x01) /* move pages instead of copying */
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#define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */
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/* we may still block on the fd we splice */
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/* from/to, of course */
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#define SPLICE_F_MORE (0x04) /* expect more data */
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#endif
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