3e7ee3e7b3
Originally from Nick Piggin, just adapted to the newer branch. You can't check PageLRU without holding zone->lru_lock. The page release code can get away with it only because the page refcount is 0 at that point. Also, you can't reliably remove pages from the LRU unless the refcount is 0. Ever. Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Jens Axboe <axboe@suse.de>
71 lines
2.2 KiB
C
71 lines
2.2 KiB
C
#ifndef _LINUX_PIPE_FS_I_H
|
|
#define _LINUX_PIPE_FS_I_H
|
|
|
|
#define PIPEFS_MAGIC 0x50495045
|
|
|
|
#define PIPE_BUFFERS (16)
|
|
|
|
#define PIPE_BUF_FLAG_STOLEN 0x01
|
|
#define PIPE_BUF_FLAG_LRU 0x02
|
|
|
|
struct pipe_buffer {
|
|
struct page *page;
|
|
unsigned int offset, len;
|
|
struct pipe_buf_operations *ops;
|
|
unsigned int flags;
|
|
};
|
|
|
|
struct pipe_buf_operations {
|
|
int can_merge;
|
|
void * (*map)(struct file *, struct pipe_inode_info *, struct pipe_buffer *);
|
|
void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *);
|
|
void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
|
|
int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
|
|
};
|
|
|
|
struct pipe_inode_info {
|
|
wait_queue_head_t wait;
|
|
unsigned int nrbufs, curbuf;
|
|
struct pipe_buffer bufs[PIPE_BUFFERS];
|
|
struct page *tmp_page;
|
|
unsigned int start;
|
|
unsigned int readers;
|
|
unsigned int writers;
|
|
unsigned int waiting_writers;
|
|
unsigned int r_counter;
|
|
unsigned int w_counter;
|
|
struct fasync_struct *fasync_readers;
|
|
struct fasync_struct *fasync_writers;
|
|
};
|
|
|
|
/* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
|
|
memory allocation, whereas PIPE_BUF makes atomicity guarantees. */
|
|
#define PIPE_SIZE PAGE_SIZE
|
|
|
|
#define PIPE_MUTEX(inode) (&(inode).i_mutex)
|
|
#define PIPE_WAIT(inode) (&(inode).i_pipe->wait)
|
|
#define PIPE_READERS(inode) ((inode).i_pipe->readers)
|
|
#define PIPE_WRITERS(inode) ((inode).i_pipe->writers)
|
|
#define PIPE_WAITING_WRITERS(inode) ((inode).i_pipe->waiting_writers)
|
|
#define PIPE_RCOUNTER(inode) ((inode).i_pipe->r_counter)
|
|
#define PIPE_WCOUNTER(inode) ((inode).i_pipe->w_counter)
|
|
#define PIPE_FASYNC_READERS(inode) (&((inode).i_pipe->fasync_readers))
|
|
#define PIPE_FASYNC_WRITERS(inode) (&((inode).i_pipe->fasync_writers))
|
|
|
|
/* Drop the inode semaphore and wait for a pipe event, atomically */
|
|
void pipe_wait(struct inode * inode);
|
|
|
|
struct inode* pipe_new(struct inode* inode);
|
|
void free_pipe_info(struct inode* inode);
|
|
|
|
/*
|
|
* splice is tied to pipes as a transport (at least for now), so we'll just
|
|
* add the splice flags here.
|
|
*/
|
|
#define SPLICE_F_MOVE (0x01) /* move pages instead of copying */
|
|
#define SPLICE_F_NONBLOCK (0x02) /* don't block on the pipe splicing (but */
|
|
/* we may still block on the fd we splice */
|
|
/* from/to, of course */
|
|
#define SPLICE_F_MORE (0x04) /* expect more data */
|
|
|
|
#endif
|