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fs/direct-io.c: don't try to allocate more than BIO_MAX_PAGES in a bio 

When using devices that support max_segments > BIO_MAX_PAGES (256), direct
IO tries to allocate a bio with more pages than allowed, which leads to an
oops in dio_bio_alloc().  Clamp the request to the supported maximum, and
change dio_bio_alloc() to reflect that bio_alloc() will always return a
bio when called with __GFP_WAIT and a valid number of vectors.

[akpm@linux-foundation.org: remove redundant BUG_ON()]
Signed-off-by: David Dillow <dillowda@ornl.gov>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Dillow 2011-01-20 14:44:22 -08:00 committed by Linus Torvalds
parent 82478fb7bc
commit 20d9600cb4
1 changed files with 7 additions and 3 deletions
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10
fs/direct-io.c
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@ -325,12 +325,16 @@ void dio_end_io(struct bio *bio, int error)
}
EXPORT_SYMBOL_GPL(dio_end_io);
static int
static void
dio_bio_alloc(struct dio *dio, struct block_device *bdev,
sector_t first_sector, int nr_vecs)
{
struct bio *bio;
/*
* bio_alloc() is guaranteed to return a bio when called with
* __GFP_WAIT and we request a valid number of vectors.
*/
bio = bio_alloc(GFP_KERNEL, nr_vecs);
bio->bi_bdev = bdev;
@ -342,7 +346,6 @@ dio_bio_alloc(struct dio *dio, struct block_device *bdev,
dio->bio = bio;
dio->logical_offset_in_bio = dio->cur_page_fs_offset;
return 0;
}
/*
@ -583,8 +586,9 @@ static int dio_new_bio(struct dio *dio, sector_t start_sector)
goto out;
sector = start_sector << (dio->blkbits - 9);
nr_pages = min(dio->pages_in_io, bio_get_nr_vecs(dio->map_bh.b_bdev));
nr_pages = min(nr_pages, BIO_MAX_PAGES);
BUG_ON(nr_pages <= 0);
ret = dio_bio_alloc(dio, dio->map_bh.b_bdev, sector, nr_pages);
dio_bio_alloc(dio, dio->map_bh.b_bdev, sector, nr_pages);
dio->boundary = 0;
out:
return ret;