path: root/fs
diff options
authorDavid Dillow <dillowda@ornl.gov>2011-01-20 14:44:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-20 17:02:05 -0800
commit20d9600cb407b0b55fef6ee814b60345c6f58264 (patch)
treea023082339b33c55e8def552abecd441ffe92fb5 /fs
parentmm: compaction: prevent division-by-zero during user-requested compaction (diff)
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>
Diffstat (limited to 'fs')
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 85882f6ba5f7..b044705eedd4 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -325,12 +325,16 @@ void dio_end_io(struct bio *bio, int error)
-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;
return ret;