The patch titled
dm io: fix bi_max_vecs
has been added to the -mm tree. Its filename is
dm-io-fix-bi_max_vecs.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: dm io: fix bi_max_vecs
From: Heinz Mauelshagen <hjm@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>
Cc: Milan Broz <mbroz@xxxxxxxxxx>
Cc: dm-devel@xxxxxxxxxx
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/md/dm-io.c | 15 +++++++++------
1 files changed, 9 insertions(+), 6 deletions(-)
diff -puN drivers/md/dm-io.c~dm-io-fix-bi_max_vecs drivers/md/dm-io.c
--- a/drivers/md/dm-io.c~dm-io-fix-bi_max_vecs
+++ a/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, unsign
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 i
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
}
/*
- * 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);
_
Patches currently in -mm which might be from hjm@xxxxxxxxxx are
dm-io-fix-bi_max_vecs.patch
-
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