From 196d38bccfcfa32faed8c561868336fdfa0fe8e4 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Sat, 23 Nov 2013 18:34:15 -0800 Subject: block: Generic bio chaining This adds a generic mechanism for chaining bio completions. This is going to be used for a bio_split() replacement, and it turns out to be very useful in a fair amount of driver code - a fair number of drivers were implementing this in their own roundabout ways, often painfully. Note that this means it's no longer to call bio_endio() more than once on the same bio! This can cause problems for drivers that save/restore bi_end_io. Arguably they shouldn't be saving/restoring bi_end_io at all - in all but the simplest cases they'd be better off just cloning the bio, and immutable biovecs is making bio cloning cheaper. But for now, we add a bio_endio_nodec() for these cases. Signed-off-by: Kent Overstreet Cc: Jens Axboe --- drivers/md/dm-cache-target.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/md/dm-cache-target.c') diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 86f9c83eb30c..bf3a206abd78 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -765,6 +765,12 @@ static void writethrough_endio(struct bio *bio, int err) dm_unhook_bio(&pb->hook_info, bio); + /* + * Must bump bi_remaining to allow bio to complete with + * restored bi_end_io. + */ + atomic_inc(&bio->bi_remaining); + if (err) { bio_endio(bio, err); return; -- cgit v1.2.3