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authorHeinz Mauelshagen <hjm@redhat.com>2006-12-08 02:41:01 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-08 08:29:08 -0800
commitf00b16ad665a9b489d46f612679181f3f914917b (patch)
treefc39bc1e04e063f8c5eda29f79d33a3194bb56fc /drivers/md/dm-io.c
parent5cd307c5655c0b76d563b5f3f911742a32746841 (diff)
[PATCH] dm io: fix bi_max_vecs
The existing code allocates an extra slot in bi_io_vec[] and uses it to store the region number. This patch hides the extra slot from bio_add_page() so the region number can't get overwritten. Also remove a hard-coded SECTOR_SHIFT and fix a typo in a comment. Signed-off-by: Heinz Mauelshagen <hjm@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: Milan Broz <mbroz@redhat.com> Cc: dm-devel@redhat.com Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/md/dm-io.c')
-rw-r--r--drivers/md/dm-io.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index da663d2ff55..4eb73d39521 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -92,12 +92,12 @@ void dm_io_put(unsigned int num_pages)
*---------------------------------------------------------------*/
static inline void bio_set_region(struct bio *bio, unsigned region)
{
- bio->bi_io_vec[bio->bi_max_vecs - 1].bv_len = region;
+ bio->bi_io_vec[bio->bi_max_vecs].bv_len = region;
}
static inline unsigned bio_get_region(struct bio *bio)
{
- return bio->bi_io_vec[bio->bi_max_vecs - 1].bv_len;
+ return bio->bi_io_vec[bio->bi_max_vecs].bv_len;
}
/*-----------------------------------------------------------------
@@ -136,6 +136,7 @@ static int endio(struct bio *bio, unsigned int done, int error)
zero_fill_bio(bio);
dec_count(io, bio_get_region(bio), error);
+ bio->bi_max_vecs++;
bio_put(bio);
return 0;
@@ -250,16 +251,18 @@ static void do_region(int rw, unsigned int region, struct io_region *where,
while (remaining) {
/*
- * Allocate a suitably sized bio, we add an extra
- * bvec for bio_get/set_region().
+ * Allocate a suitably sized-bio: we add an extra
+ * bvec for bio_get/set_region() and decrement bi_max_vecs
+ * to hide it from bio_add_page().
*/
- num_bvecs = (remaining / (PAGE_SIZE >> 9)) + 2;
+ num_bvecs = (remaining / (PAGE_SIZE >> SECTOR_SHIFT)) + 2;
bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, _bios);
bio->bi_sector = where->sector + (where->count - remaining);
bio->bi_bdev = where->bdev;
bio->bi_end_io = endio;
bio->bi_private = io;
bio->bi_destructor = dm_bio_destructor;
+ bio->bi_max_vecs--;
bio_set_region(bio, region);
/*
@@ -302,7 +305,7 @@ static void dispatch_io(int rw, unsigned int num_regions,
}
/*
- * Drop the extra refence that we were holding to avoid
+ * Drop the extra reference that we were holding to avoid
* the io being completed too early.
*/
dec_count(io, 0, 0);