4 * Defines the structures used to track abstract kernel-space io buffers.
8 #ifndef __LINUX_IOBUF_H
9 #define __LINUX_IOBUF_H
12 #include <linux/init.h>
13 #include <linux/wait.h>
14 #include <asm/atomic.h>
17 * The kiobuf structure describes a physical set of pages reserved
18 * locked for IO. The reference counts on each page will have been
19 * incremented, and the flags field will indicate whether or not we have
20 * pre-locked all of the pages for IO.
22 * kiobufs may be passed in arrays to form a kiovec, but we must
23 * preserve the property that no page is present more than once over the
27 #define KIO_MAX_ATOMIC_IO 512 /* in kb */
28 #define KIO_STATIC_PAGES (KIO_MAX_ATOMIC_IO / (PAGE_SIZE >> 10) + 1)
29 #define KIO_MAX_SECTORS (KIO_MAX_ATOMIC_IO * 2)
31 /* The main kiobuf struct used for all our IO! */
35 int nr_pages; /* Pages actually referenced */
36 int array_len; /* Space in the allocated lists */
37 int offset; /* Offset to start of valid data */
38 int length; /* Number of valid bytes of data */
40 unsigned int locked : 1; /* If set, pages has been locked */
42 struct page ** maplist;
43 struct buffer_head ** bh;
44 unsigned long * blocks;
46 /* Dynamic state for IO completion: */
47 atomic_t io_count; /* IOs still in progress */
48 int errno; /* Status of completed IO */
49 void (*end_io) (struct kiobuf *); /* Completion callback */
50 wait_queue_head_t wait_queue;
56 int map_user_kiobuf(int rw, struct kiobuf *, unsigned long va, size_t len);
57 void unmap_kiobuf(struct kiobuf *iobuf);
58 int lock_kiovec(int nr, struct kiobuf *iovec[], int wait);
59 int unlock_kiovec(int nr, struct kiobuf *iovec[]);
60 void mark_dirty_kiobuf(struct kiobuf *iobuf, int bytes);
64 void end_kio_request(struct kiobuf *, int);
65 void simple_wakeup_kiobuf(struct kiobuf *);
66 int alloc_kiovec(int nr, struct kiobuf **);
67 void free_kiovec(int nr, struct kiobuf **);
68 int expand_kiobuf(struct kiobuf *, int);
69 void kiobuf_wait_for_io(struct kiobuf *);
70 extern int alloc_kiobuf_bhs(struct kiobuf *);
71 extern void free_kiobuf_bhs(struct kiobuf *);
75 int brw_kiovec(int rw, int nr, struct kiobuf *iovec[],
76 kdev_t dev, unsigned long b[], int size);
78 #endif /* __LINUX_IOBUF_H */