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authorJun'ichi Nomura <j-nomura@ce.jp.nec.com>2007-07-12 17:27:45 +0100
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-12 15:01:08 -0700
commit596f138eede0c113aa655937c8be85fc15ccd61c (patch)
treeefd4e3d67b759b84bb1e72f9d50897d275085f7c /drivers/md/dm-io.c
parentc95bc206da4bc9838bad826883f8f461a972e441 (diff)
downloadblackbird-op-linux-596f138eede0c113aa655937c8be85fc15ccd61c.tar.gz
blackbird-op-linux-596f138eede0c113aa655937c8be85fc15ccd61c.zip
dm io: fix panic on large request
bio_alloc_bioset() will return NULL if 'num_vecs' is too large. Use bio_get_nr_vecs() to get estimation of maximum number. Cc: stable@kernel.org Signed-off-by: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/md/dm-io.c')
-rw-r--r--drivers/md/dm-io.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 352c6fbeac53..f3a772486437 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -293,7 +293,10 @@ static void do_region(int rw, unsigned int region, struct io_region *where,
* bvec for bio_get/set_region() and decrement bi_max_vecs
* to hide it from bio_add_page().
*/
- num_bvecs = (remaining / (PAGE_SIZE >> SECTOR_SHIFT)) + 2;
+ num_bvecs = dm_sector_div_up(remaining,
+ (PAGE_SIZE >> SECTOR_SHIFT));
+ num_bvecs = 1 + min_t(int, bio_get_nr_vecs(where->bdev),
+ num_bvecs);
bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
bio->bi_sector = where->sector + (where->count - remaining);
bio->bi_bdev = where->bdev;
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