79 lines
2.2 KiB
C
79 lines
2.2 KiB
C
/*
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* iobuf.h
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*
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* Defines the structures used to track abstract kernel-space io buffers.
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*
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*/
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#ifndef __LINUX_IOBUF_H
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#define __LINUX_IOBUF_H
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <linux/wait.h>
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#include <asm/atomic.h>
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/*
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* The kiobuf structure describes a physical set of pages reserved
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* locked for IO. The reference counts on each page will have been
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* incremented, and the flags field will indicate whether or not we have
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* pre-locked all of the pages for IO.
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*
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* kiobufs may be passed in arrays to form a kiovec, but we must
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* preserve the property that no page is present more than once over the
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* entire iovec.
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*/
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#define KIO_MAX_ATOMIC_IO 512 /* in kb */
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#define KIO_STATIC_PAGES (KIO_MAX_ATOMIC_IO / (PAGE_SIZE >> 10) + 1)
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#define KIO_MAX_SECTORS (KIO_MAX_ATOMIC_IO * 2)
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/* The main kiobuf struct used for all our IO! */
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struct kiobuf
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{
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int nr_pages; /* Pages actually referenced */
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int array_len; /* Space in the allocated lists */
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int offset; /* Offset to start of valid data */
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int length; /* Number of valid bytes of data */
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unsigned int locked : 1; /* If set, pages has been locked */
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struct page ** maplist;
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struct buffer_head ** bh;
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unsigned long * blocks;
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/* Dynamic state for IO completion: */
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atomic_t io_count; /* IOs still in progress */
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int errno; /* Status of completed IO */
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void (*end_io) (struct kiobuf *); /* Completion callback */
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wait_queue_head_t wait_queue;
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};
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/* mm/memory.c */
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int map_user_kiobuf(int rw, struct kiobuf *, unsigned long va, size_t len);
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void unmap_kiobuf(struct kiobuf *iobuf);
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int lock_kiovec(int nr, struct kiobuf *iovec[], int wait);
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int unlock_kiovec(int nr, struct kiobuf *iovec[]);
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void mark_dirty_kiobuf(struct kiobuf *iobuf, int bytes);
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/* fs/iobuf.c */
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void end_kio_request(struct kiobuf *, int);
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void simple_wakeup_kiobuf(struct kiobuf *);
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int alloc_kiovec(int nr, struct kiobuf **);
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void free_kiovec(int nr, struct kiobuf **);
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int expand_kiobuf(struct kiobuf *, int);
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void kiobuf_wait_for_io(struct kiobuf *);
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extern int alloc_kiobuf_bhs(struct kiobuf *);
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extern void free_kiobuf_bhs(struct kiobuf *);
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/* fs/buffer.c */
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int brw_kiovec(int rw, int nr, struct kiobuf *iovec[],
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kdev_t dev, unsigned long b[], int size);
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#endif /* __LINUX_IOBUF_H */
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