This series fixes some incorrect accounting from merging discard requests. The first patch fixes merging two discard requests by having a special case for merging these using the unique constraints discards have. The second fixes merging a new discard bio into an existing request. Previously all the schedulers defaulted to a front merge, so the patch just checks merge type and adds a 'case' for handling discard in each of the callers. I've only been able to test with mq-deadline on NVMe as that is the only driver currently supporting multiple discard ranges in a single command. v1 -> v2: Fixed patch 1 based on feedback from Jens, tested with recreate sequence. Added 2nd patch for merging discard bios into existing requests. Keith Busch (2): block: Merge discard requests as a special case block: Handle merging discards in IO schedulers block/bfq-iosched.c | 2 +- block/blk-core.c | 4 ++++ block/blk-merge.c | 29 ++++++++++++++++++++++++++++- block/blk-mq-sched.c | 2 ++ block/cfq-iosched.c | 2 +- block/deadline-iosched.c | 4 +++- block/elevator.c | 2 +- block/mq-deadline.c | 2 +- 8 files changed, 41 insertions(+), 6 deletions(-) -- 2.14.3
