From: Heinz Mauelshagen <hjm@xxxxxxxxxx>
Delay decrementing the 'struct io' reference count until after the bio has
been freed so that a bio destructor function may reference it.
Required by a later patch.
Signed-off-by: Heinz Mauelshagen <hjm@xxxxxxxxxx>
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>
Cc: Milan Broz <mbroz@xxxxxxxxxx>
---
drivers/md/dm-io.c | 12 ++++++++++--
1 files changed, 10 insertions(+), 2 deletions(-)
Index: linux-2.6.21/drivers/md/dm-io.c
===================================================================
--- linux-2.6.21.orig/drivers/md/dm-io.c 2007-05-01 17:38:32.000000000 +0100
+++ linux-2.6.21/drivers/md/dm-io.c 2007-05-01 17:40:52.000000000 +0100
@@ -126,7 +126,8 @@ static void dec_count(struct io *io, uns
static int endio(struct bio *bio, unsigned int done, int error)
{
- struct io *io = (struct io *) bio->bi_private;
+ struct io *io;
+ unsigned region;
/* keep going until we've finished */
if (bio->bi_size)
@@ -135,10 +136,17 @@ static int endio(struct bio *bio, unsign
if (error && bio_data_dir(bio) == READ)
zero_fill_bio(bio);
- dec_count(io, bio_get_region(bio), error);
+ /*
+ * The bio destructor in bio_put() may use the io object.
+ */
+ io = bio->bi_private;
+ region = bio_get_region(bio);
+
bio->bi_max_vecs++;
bio_put(bio);
+ dec_count(io, region, error);
+
return 0;
}
--
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