From: Jonathan Brassow A clear_region function is permitted to block (in practice, rare) but gets called in rh_update_states() with a spinlock held. The bits being marked and cleared by the above functions are used to update the on-disk log, but are never read directly. We can perform these operations outside the spinlock since the bits are only changed within one thread viz. - mark_region in rh_inc() - clear_region in rh_update_states(). So, we grab the clean_regions list items via list_splice() within the spinlock and defer clear_region() until we iterate over the list for deletion - similar to how the recovered_regions list is already handled. We then move the flush() call down to ensure it encapsulates the changes which are done by the later calls to clear_region(). Signed-off-by: Jonathan Brassow Signed-off-by: Alasdair G Kergon --- drivers/md/dm-raid1.c | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-) Index: linux/drivers/md/dm-raid1.c =================================================================== --- linux.orig/drivers/md/dm-raid1.c 2007-07-12 17:04:02.000000000 +0100 +++ linux/drivers/md/dm-raid1.c 2007-07-12 17:04:04.000000000 +0100 @@ -378,10 +378,8 @@ static void rh_update_states(struct regi list_splice(&rh->clean_regions, &clean); INIT_LIST_HEAD(&rh->clean_regions); - list_for_each_entry (reg, &clean, list) { - rh->log->type->clear_region(rh->log, reg->key); + list_for_each_entry(reg, &clean, list) list_del(®->hash_list); - } } if (!list_empty(&rh->recovered_regions)) { @@ -405,10 +403,12 @@ static void rh_update_states(struct regi mempool_free(reg, rh->region_pool); } - rh->log->type->flush(rh->log); - - list_for_each_entry_safe (reg, next, &clean, list) + list_for_each_entry_safe(reg, next, &clean, list) { + rh->log->type->clear_region(rh->log, reg->key); mempool_free(reg, rh->region_pool); + } + + rh->log->type->flush(rh->log); } static void rh_inc(struct region_hash *rh, region_t region)