This is simple refactoring that moves code for modifying the semaphore cow_count into separate functions. It is needed by the following patch.
Signed-off-by: Mikulas Patocka <[email protected]> Cc: [email protected] # v5.0+ Fixes: 721b1d98fb51 ("dm snapshot: Fix excessive memory usage and workqueue stalls") --- drivers/md/dm-snap.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) Index: linux-2.6/drivers/md/dm-snap.c =================================================================== --- linux-2.6.orig/drivers/md/dm-snap.c 2019-10-01 15:19:20.000000000 +0200 +++ linux-2.6/drivers/md/dm-snap.c 2019-10-01 15:23:10.000000000 +0200 @@ -1512,6 +1512,16 @@ static void snapshot_dtr(struct dm_targe kfree(s); } +static void account_start_copy(struct dm_snapshot *s) +{ + down(&s->cow_count); +} + +static void account_end_copy(struct dm_snapshot *s) +{ + up(&s->cow_count); +} + /* * Flush a list of buffers. */ @@ -1732,7 +1742,7 @@ static void copy_callback(int read_err, rb_link_node(&pe->out_of_order_node, parent, p); rb_insert_color(&pe->out_of_order_node, &s->out_of_order_tree); } - up(&s->cow_count); + account_end_copy(s); } /* @@ -1756,7 +1766,7 @@ static void start_copy(struct dm_snap_pe dest.count = src.count; /* Hand over to kcopyd */ - down(&s->cow_count); + account_start_copy(s); dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, copy_callback, pe); } @@ -1776,7 +1786,7 @@ static void start_full_bio(struct dm_sna pe->full_bio = bio; pe->full_bio_end_io = bio->bi_end_io; - down(&s->cow_count); + account_start_copy(s); callback_data = dm_kcopyd_prepare_callback(s->kcopyd_client, copy_callback, pe); @@ -1866,7 +1876,7 @@ static void zero_callback(int read_err, struct bio *bio = context; struct dm_snapshot *s = bio->bi_private; - up(&s->cow_count); + account_end_copy(s); bio->bi_status = write_err ? BLK_STS_IOERR : 0; bio_endio(bio); } @@ -1880,7 +1890,7 @@ static void zero_exception(struct dm_sna dest.sector = bio->bi_iter.bi_sector; dest.count = s->store->chunk_size; - down(&s->cow_count); + account_start_copy(s); WARN_ON_ONCE(bio->bi_private); bio->bi_private = s; dm_kcopyd_zero(s->kcopyd_client, 1, &dest, 0, zero_callback, bio); -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
