Commit 392aaa18 authored by Jens Axboe's avatar Jens Axboe

[PATCH] partial bio completion notification

Make bio->bi_end_io() take bytes_done and actual error as argument. This
enables partial completion of bio's, which is important for latency
reasons (bio can be huge, for slow media we want page-by-page
completions).

I think I got most of the bi_end_io() functions out there, but I might
have missed a few. For the record, if you don't care about partial
completions and just want to be notified when the entire bio completes,
add a

	if (bio->bi_size)
		return 1;

to the top of your bi_end_io(). It should return 0 on completion.
bio_endio() will decrement bio->bi_size appropriately, it's recommended
for people to go through that. Otherwise they will have to control
BIO_UPTODATE and bi_size decrement themselves, there's really no reason
to do that. I've deliberately avoided doing any functional changes to
any of the end_io functions, as I think that would only make the patch
more complex. It's simple right now, but this being i/o paths I prefer
(as usual) to be careful and take small steps. The mpage_end_io_read()
do-vecs-at-the-time change can come right after this, for instance.
parent cf780a87
...@@ -1567,10 +1567,11 @@ static inline void complete_buffers(struct bio *bio, int status) ...@@ -1567,10 +1567,11 @@ static inline void complete_buffers(struct bio *bio, int status)
{ {
while (bio) { while (bio) {
struct bio *xbh = bio->bi_next; struct bio *xbh = bio->bi_next;
int nr_sectors = bio_sectors(bio);
bio->bi_next = NULL; bio->bi_next = NULL;
blk_finished_io(bio_sectors(bio)); blk_finished_io(len);
bio_endio(bio, status); bio_endio(bio, nr_sectors << 9, status ? 0 : -EIO);
bio = xbh; bio = xbh;
} }
......
...@@ -911,11 +911,13 @@ static inline void complete_buffers(struct bio *bio, int ok) ...@@ -911,11 +911,13 @@ static inline void complete_buffers(struct bio *bio, int ok)
{ {
struct bio *xbh; struct bio *xbh;
while(bio) { while(bio) {
int nr_sectors = bio_sectors(bio);
xbh = bio->bi_next; xbh = bio->bi_next;
bio->bi_next = NULL; bio->bi_next = NULL;
blk_finished_io(bio_sectors(bio)); blk_finished_io(nr_sectors);
bio_endio(bio, ok); bio_endio(bio, nr_sectors << 9, ok ? 0 : -EIO);
bio = xbh; bio = xbh;
} }
......
...@@ -3846,9 +3846,13 @@ static int check_floppy_change(kdev_t dev) ...@@ -3846,9 +3846,13 @@ static int check_floppy_change(kdev_t dev)
* a disk in the drive, and whether that disk is writable. * a disk in the drive, and whether that disk is writable.
*/ */
static void floppy_rb0_complete(struct bio *bio) static int floppy_rb0_complete(struct bio *bio, unsigned int bytes_done, int err)
{ {
if (bio->bi_size)
return 1;
complete((struct completion*)bio->bi_private); complete((struct completion*)bio->bi_private);
return 0;
} }
static int __floppy_read_block_0(struct block_device *bdev) static int __floppy_read_block_0(struct block_device *bdev)
......
...@@ -1576,10 +1576,8 @@ static int __make_request(request_queue_t *q, struct bio *bio) ...@@ -1576,10 +1576,8 @@ static int __make_request(request_queue_t *q, struct bio *bio)
/* /*
* READA bit set * READA bit set
*/ */
if (bio->bi_rw & (1 << BIO_RW_AHEAD)) { if (bio_flagged(bio, BIO_RW_AHEAD))
set_bit(BIO_RW_BLOCK, &bio->bi_flags);
goto end_io; goto end_io;
}
freereq = get_request_wait(q, rw); freereq = get_request_wait(q, rw);
spin_lock_irq(q->queue_lock); spin_lock_irq(q->queue_lock);
...@@ -1616,7 +1614,7 @@ static int __make_request(request_queue_t *q, struct bio *bio) ...@@ -1616,7 +1614,7 @@ static int __make_request(request_queue_t *q, struct bio *bio)
return 0; return 0;
end_io: end_io:
bio->bi_end_io(bio); bio_endio(bio, nr_sectors << 9, -EWOULDBLOCK);
return 0; return 0;
} }
...@@ -1705,7 +1703,7 @@ void generic_make_request(struct bio *bio) ...@@ -1705,7 +1703,7 @@ void generic_make_request(struct bio *bio)
bdevname(bio->bi_bdev), bdevname(bio->bi_bdev),
(long long) bio->bi_sector); (long long) bio->bi_sector);
end_io: end_io:
bio->bi_end_io(bio); bio_endio(bio, 0, -EIO);
break; break;
} }
...@@ -1825,6 +1823,7 @@ int end_that_request_first(struct request *req, int uptodate, int nr_sectors) ...@@ -1825,6 +1823,7 @@ int end_that_request_first(struct request *req, int uptodate, int nr_sectors)
total_nsect = 0; total_nsect = 0;
while ((bio = req->bio)) { while ((bio = req->bio)) {
nsect = bio_iovec(bio)->bv_len >> 9; nsect = bio_iovec(bio)->bv_len >> 9;
total_nsect += nsect;
BIO_BUG_ON(bio_iovec(bio)->bv_len > bio->bi_size); BIO_BUG_ON(bio_iovec(bio)->bv_len > bio->bi_size);
...@@ -1834,38 +1833,31 @@ int end_that_request_first(struct request *req, int uptodate, int nr_sectors) ...@@ -1834,38 +1833,31 @@ int end_that_request_first(struct request *req, int uptodate, int nr_sectors)
if (unlikely(nsect > nr_sectors)) { if (unlikely(nsect > nr_sectors)) {
int partial = nr_sectors << 9; int partial = nr_sectors << 9;
bio->bi_size -= partial;
bio_iovec(bio)->bv_offset += partial; bio_iovec(bio)->bv_offset += partial;
bio_iovec(bio)->bv_len -= partial; bio_iovec(bio)->bv_len -= partial;
blk_recalc_rq_sectors(req, nr_sectors); blk_recalc_rq_sectors(req, total_nsect);
blk_recalc_rq_segments(req); blk_recalc_rq_segments(req);
bio_endio(bio, partial, !uptodate ? -EIO : 0);
return 1; return 1;
} }
/* /*
* account transfer * if bio->bi_end_io returns 0, this bio is done. move on
*/ */
bio->bi_size -= bio_iovec(bio)->bv_len; req->bio = bio->bi_next;
bio->bi_idx++; if (bio_endio(bio, nsect << 9, !uptodate ? -EIO : 0)) {
bio->bi_idx++;
req->bio = bio;
}
nr_sectors -= nsect; nr_sectors -= nsect;
total_nsect += nsect;
if (!bio->bi_size) {
req->bio = bio->bi_next;
bio_endio(bio, uptodate);
total_nsect = 0;
}
if ((bio = req->bio)) { if ((bio = req->bio)) {
blk_recalc_rq_sectors(req, nsect);
/* /*
* end more in this run, or just return 'not-done' * end more in this run, or just return 'not-done'
*/ */
if (unlikely(nr_sectors <= 0)) { if (unlikely(nr_sectors <= 0)) {
blk_recalc_rq_sectors(req, total_nsect);
blk_recalc_rq_segments(req); blk_recalc_rq_segments(req);
return 1; return 1;
} }
......
...@@ -374,7 +374,7 @@ static int do_bio_filebacked(struct loop_device *lo, struct bio *bio) ...@@ -374,7 +374,7 @@ static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
return ret; return ret;
} }
static void loop_end_io_transfer(struct bio *); static int loop_end_io_transfer(struct bio *, unsigned int, int);
static void loop_put_buffer(struct bio *bio) static void loop_put_buffer(struct bio *bio)
{ {
/* /*
...@@ -382,6 +382,7 @@ static void loop_put_buffer(struct bio *bio) ...@@ -382,6 +382,7 @@ static void loop_put_buffer(struct bio *bio)
*/ */
if (bio && bio->bi_end_io == loop_end_io_transfer) { if (bio && bio->bi_end_io == loop_end_io_transfer) {
int i; int i;
for (i = 0; i < bio->bi_vcnt; i++) for (i = 0; i < bio->bi_vcnt; i++)
__free_page(bio->bi_io_vec[i].bv_page); __free_page(bio->bi_io_vec[i].bv_page);
...@@ -432,19 +433,23 @@ static struct bio *loop_get_bio(struct loop_device *lo) ...@@ -432,19 +433,23 @@ static struct bio *loop_get_bio(struct loop_device *lo)
* bi_end_io context (we don't want to do decrypt of a page with irqs * bi_end_io context (we don't want to do decrypt of a page with irqs
* disabled) * disabled)
*/ */
static void loop_end_io_transfer(struct bio *bio) static int loop_end_io_transfer(struct bio *bio, unsigned int bytes_done, int err)
{ {
struct bio *rbh = bio->bi_private; struct bio *rbh = bio->bi_private;
struct loop_device *lo = &loop_dev[minor(to_kdev_t(rbh->bi_bdev->bd_dev))]; struct loop_device *lo = &loop_dev[minor(to_kdev_t(rbh->bi_bdev->bd_dev))];
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
if (!uptodate || bio_rw(bio) == WRITE) { if (bio->bi_size)
bio_endio(rbh, uptodate); return 1;
if (!err || bio_rw(bio) == WRITE) {
bio_endio(rbh, rbh->bi_size, err);
if (atomic_dec_and_test(&lo->lo_pending)) if (atomic_dec_and_test(&lo->lo_pending))
up(&lo->lo_bh_mutex); up(&lo->lo_bh_mutex);
loop_put_buffer(bio); loop_put_buffer(bio);
} else } else
loop_add_bio(lo, bio); loop_add_bio(lo, bio);
return 0;
} }
static struct bio *loop_get_buffer(struct loop_device *lo, struct bio *rbh) static struct bio *loop_get_buffer(struct loop_device *lo, struct bio *rbh)
...@@ -553,7 +558,7 @@ static int loop_make_request(request_queue_t *q, struct bio *old_bio) ...@@ -553,7 +558,7 @@ static int loop_make_request(request_queue_t *q, struct bio *old_bio)
up(&lo->lo_bh_mutex); up(&lo->lo_bh_mutex);
loop_put_buffer(new_bio); loop_put_buffer(new_bio);
out: out:
bio_io_error(old_bio); bio_io_error(old_bio, old_bio->bi_size);
return 0; return 0;
inactive: inactive:
spin_unlock_irq(&lo->lo_lock); spin_unlock_irq(&lo->lo_lock);
...@@ -569,13 +574,13 @@ static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio) ...@@ -569,13 +574,13 @@ static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio)
*/ */
if (lo->lo_flags & LO_FLAGS_DO_BMAP) { if (lo->lo_flags & LO_FLAGS_DO_BMAP) {
ret = do_bio_filebacked(lo, bio); ret = do_bio_filebacked(lo, bio);
bio_endio(bio, !ret); bio_endio(bio, bio->bi_size, ret);
} else { } else {
struct bio *rbh = bio->bi_private; struct bio *rbh = bio->bi_private;
ret = bio_transfer(lo, bio, rbh); ret = bio_transfer(lo, bio, rbh);
bio_endio(rbh, !ret); bio_endio(rbh, rbh->bi_size, ret);
loop_put_buffer(bio); loop_put_buffer(bio);
} }
} }
......
...@@ -277,11 +277,10 @@ static int rd_make_request(request_queue_t * q, struct bio *sbh) ...@@ -277,11 +277,10 @@ static int rd_make_request(request_queue_t * q, struct bio *sbh)
if (rd_blkdev_bio_IO(sbh, minor)) if (rd_blkdev_bio_IO(sbh, minor))
goto fail; goto fail;
set_bit(BIO_UPTODATE, &sbh->bi_flags); bio_endio(sbh, sbh->bi_size, 0);
sbh->bi_end_io(sbh);
return 0; return 0;
fail: fail:
bio_io_error(sbh); bio_io_error(sbh, sbh->bi_size);
return 0; return 0;
} }
......
...@@ -401,12 +401,16 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len, ...@@ -401,12 +401,16 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
return 0; return 0;
} }
static void bio_end_io_kio(struct bio *bio) static int bio_end_io_kio(struct bio *bio, unsigned int bytes_done, int error)
{ {
struct kiobuf *kio = (struct kiobuf *) bio->bi_private; struct kiobuf *kio = (struct kiobuf *) bio->bi_private;
end_kio_request(kio, test_bit(BIO_UPTODATE, &bio->bi_flags)); if (bio->bi_size)
return 1;
end_kio_request(kio, error);
bio_put(bio); bio_put(bio);
return 0;
} }
/** /**
...@@ -519,15 +523,15 @@ void ll_rw_kio(int rw, struct kiobuf *kio, struct block_device *bdev, sector_t s ...@@ -519,15 +523,15 @@ void ll_rw_kio(int rw, struct kiobuf *kio, struct block_device *bdev, sector_t s
end_kio_request(kio, !err); end_kio_request(kio, !err);
} }
void bio_endio(struct bio *bio, int uptodate) int bio_endio(struct bio *bio, unsigned int bytes_done, int error)
{ {
if (uptodate) if (!error)
set_bit(BIO_UPTODATE, &bio->bi_flags); set_bit(BIO_UPTODATE, &bio->bi_flags);
else else
clear_bit(BIO_UPTODATE, &bio->bi_flags); clear_bit(BIO_UPTODATE, &bio->bi_flags);
if (bio->bi_end_io) bio->bi_size -= bytes_done;
bio->bi_end_io(bio); return bio->bi_end_io(bio, bytes_done, error);
} }
static void __init biovec_init_pools(void) static void __init biovec_init_pools(void)
......
...@@ -2413,12 +2413,16 @@ int brw_kiovec(int rw, int nr, struct kiobuf *iovec[], ...@@ -2413,12 +2413,16 @@ int brw_kiovec(int rw, int nr, struct kiobuf *iovec[],
return err ? err : transferred; return err ? err : transferred;
} }
static void end_bio_bh_io_sync(struct bio *bio) static int end_bio_bh_io_sync(struct bio *bio, unsigned int bytes_done, int err)
{ {
struct buffer_head *bh = bio->bi_private; struct buffer_head *bh = bio->bi_private;
if (bio->bi_size)
return 1;
bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags)); bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags));
bio_put(bio); bio_put(bio);
return 0;
} }
int submit_bh(int rw, struct buffer_head * bh) int submit_bh(int rw, struct buffer_head * bh)
......
...@@ -151,17 +151,21 @@ static struct page *dio_get_page(struct dio *dio) ...@@ -151,17 +151,21 @@ static struct page *dio_get_page(struct dio *dio)
* During I/O bi_private points at the dio. After I/O, bi_private is used to * During I/O bi_private points at the dio. After I/O, bi_private is used to
* implement a singly-linked list of completed BIOs, at dio->bio_list. * implement a singly-linked list of completed BIOs, at dio->bio_list.
*/ */
static void dio_bio_end_io(struct bio *bio) static int dio_bio_end_io(struct bio *bio, unsigned int bytes_done, int error)
{ {
struct dio *dio = bio->bi_private; struct dio *dio = bio->bi_private;
unsigned long flags; unsigned long flags;
if (bio->bi_size)
return 1;
spin_lock_irqsave(&dio->bio_list_lock, flags); spin_lock_irqsave(&dio->bio_list_lock, flags);
bio->bi_private = dio->bio_list; bio->bi_private = dio->bio_list;
dio->bio_list = bio; dio->bio_list = bio;
if (dio->waiter) if (dio->waiter)
wake_up_process(dio->waiter); wake_up_process(dio->waiter);
spin_unlock_irqrestore(&dio->bio_list_lock, flags); spin_unlock_irqrestore(&dio->bio_list_lock, flags);
return 0;
} }
static int static int
......
...@@ -36,11 +36,14 @@ ...@@ -36,11 +36,14 @@
* status of that page is hard. See end_buffer_async_read() for the details. * status of that page is hard. See end_buffer_async_read() for the details.
* There is no point in duplicating all that complexity. * There is no point in duplicating all that complexity.
*/ */
static void mpage_end_io_read(struct bio *bio) static int mpage_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
{ {
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
if (bio->bi_size)
return 1;
do { do {
struct page *page = bvec->bv_page; struct page *page = bvec->bv_page;
...@@ -56,13 +59,17 @@ static void mpage_end_io_read(struct bio *bio) ...@@ -56,13 +59,17 @@ static void mpage_end_io_read(struct bio *bio)
unlock_page(page); unlock_page(page);
} while (bvec >= bio->bi_io_vec); } while (bvec >= bio->bi_io_vec);
bio_put(bio); bio_put(bio);
return 0;
} }
static void mpage_end_io_write(struct bio *bio) static int mpage_end_io_write(struct bio *bio, unsigned int bytes_done, int err)
{ {
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
if (bio->bi_size)
return 1;
do { do {
struct page *page = bvec->bv_page; struct page *page = bvec->bv_page;
...@@ -74,6 +81,7 @@ static void mpage_end_io_write(struct bio *bio) ...@@ -74,6 +81,7 @@ static void mpage_end_io_write(struct bio *bio)
end_page_writeback(page); end_page_writeback(page);
} while (bvec >= bio->bi_io_vec); } while (bvec >= bio->bi_io_vec);
bio_put(bio); bio_put(bio);
return 0;
} }
struct bio *mpage_bio_submit(int rw, struct bio *bio) struct bio *mpage_bio_submit(int rw, struct bio *bio)
......
...@@ -51,7 +51,7 @@ struct bio_vec { ...@@ -51,7 +51,7 @@ struct bio_vec {
}; };
struct bio; struct bio;
typedef void (bio_end_io_t) (struct bio *); typedef int (bio_end_io_t) (struct bio *, unsigned int, int);
typedef void (bio_destructor_t) (struct bio *); typedef void (bio_destructor_t) (struct bio *);
/* /*
...@@ -161,7 +161,7 @@ struct bio { ...@@ -161,7 +161,7 @@ struct bio {
#define BIO_SEG_BOUNDARY(q, b1, b2) \ #define BIO_SEG_BOUNDARY(q, b1, b2) \
BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2))) BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
#define bio_io_error(bio) bio_endio((bio), 0) #define bio_io_error(bio, bytes) bio_endio((bio), (bytes), -EIO)
/* /*
* drivers should not use the __ version unless they _really_ want to * drivers should not use the __ version unless they _really_ want to
...@@ -194,7 +194,7 @@ struct bio { ...@@ -194,7 +194,7 @@ struct bio {
extern struct bio *bio_alloc(int, int); extern struct bio *bio_alloc(int, int);
extern void bio_put(struct bio *); extern void bio_put(struct bio *);
extern void bio_endio(struct bio *, int); extern int bio_endio(struct bio *, unsigned int, int);
struct request_queue; struct request_queue;
extern inline int bio_phys_segments(struct request_queue *, struct bio *); extern inline int bio_phys_segments(struct request_queue *, struct bio *);
extern inline int bio_hw_segments(struct request_queue *, struct bio *); extern inline int bio_hw_segments(struct request_queue *, struct bio *);
......
...@@ -291,12 +291,16 @@ static inline void copy_to_high_bio_irq(struct bio *to, struct bio *from) ...@@ -291,12 +291,16 @@ static inline void copy_to_high_bio_irq(struct bio *to, struct bio *from)
} }
} }
static inline void bounce_end_io(struct bio *bio, mempool_t *pool) static inline int bounce_end_io(struct bio *bio, unsigned int bytes_done,
int error, mempool_t *pool)
{ {
struct bio *bio_orig = bio->bi_private; struct bio *bio_orig = bio->bi_private;
struct bio_vec *bvec, *org_vec; struct bio_vec *bvec, *org_vec;
int i; int i;
if (bio->bi_size)
return 1;
if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
goto out_eio; goto out_eio;
...@@ -314,38 +318,43 @@ static inline void bounce_end_io(struct bio *bio, mempool_t *pool) ...@@ -314,38 +318,43 @@ static inline void bounce_end_io(struct bio *bio, mempool_t *pool)
} }
out_eio: out_eio:
bio_orig->bi_end_io(bio_orig); bio_endio(bio_orig, bytes_done, error);
bio_put(bio); bio_put(bio);
return 0;
} }
static void bounce_end_io_write(struct bio *bio) static int bounce_end_io_write(struct bio *bio, unsigned int bytes_done,
int error)
{ {
bounce_end_io(bio, page_pool); return bounce_end_io(bio, bytes_done, error, page_pool);
} }
static void bounce_end_io_write_isa(struct bio *bio) static int bounce_end_io_write_isa(struct bio *bio, unsigned int bytes_done,
int error)
{ {
bounce_end_io(bio, isa_page_pool); return bounce_end_io(bio, bytes_done, error, isa_page_pool);
} }
static inline void __bounce_end_io_read(struct bio *bio, mempool_t *pool) static inline int __bounce_end_io_read(struct bio *bio, unsigned int done,
int error, mempool_t *pool)
{ {
struct bio *bio_orig = bio->bi_private; struct bio *bio_orig = bio->bi_private;
if (test_bit(BIO_UPTODATE, &bio->bi_flags)) if (test_bit(BIO_UPTODATE, &bio->bi_flags))
copy_to_high_bio_irq(bio_orig, bio); copy_to_high_bio_irq(bio_orig, bio);
bounce_end_io(bio, pool); return bounce_end_io(bio, done, error, pool);
} }
static void bounce_end_io_read(struct bio *bio) static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
{ {
__bounce_end_io_read(bio, page_pool); return __bounce_end_io_read(bio, bytes_done, err, page_pool);
} }
static void bounce_end_io_read_isa(struct bio *bio) static int bounce_end_io_read_isa(struct bio *bio, unsigned int bytes_done,
int err)
{ {
return __bounce_end_io_read(bio, isa_page_pool); return __bounce_end_io_read(bio, bytes_done, err, isa_page_pool);
} }
void blk_queue_bounce(request_queue_t *q, struct bio **bio_orig) void blk_queue_bounce(request_queue_t *q, struct bio **bio_orig)
......
...@@ -47,22 +47,29 @@ get_swap_bio(int gfp_flags, struct page *page, bio_end_io_t end_io) ...@@ -47,22 +47,29 @@ get_swap_bio(int gfp_flags, struct page *page, bio_end_io_t end_io)
return bio; return bio;
} }
static void end_swap_bio_write(struct bio *bio) static int end_swap_bio_write(struct bio *bio, unsigned int bytes_done, int err)
{ {
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct page *page = bio->bi_io_vec[0].bv_page; struct page *page = bio->bi_io_vec[0].bv_page;
if (bio->bi_size)
return 1;
if (!uptodate) if (!uptodate)
SetPageError(page); SetPageError(page);
end_page_writeback(page); end_page_writeback(page);
bio_put(bio); bio_put(bio);
return 0;
} }
static void end_swap_bio_read(struct bio *bio) static int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err)
{ {
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct page *page = bio->bi_io_vec[0].bv_page; struct page *page = bio->bi_io_vec[0].bv_page;
if (bio->bi_size)
return 1;
if (!uptodate) { if (!uptodate) {
SetPageError(page); SetPageError(page);
ClearPageUptodate(page); ClearPageUptodate(page);
...@@ -71,6 +78,7 @@ static void end_swap_bio_read(struct bio *bio) ...@@ -71,6 +78,7 @@ static void end_swap_bio_read(struct bio *bio)
} }
unlock_page(page); unlock_page(page);
bio_put(bio); bio_put(bio);
return 0;
} }
/* /*
......
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