[0/4] dm: fix various issues with bio splitting code

Message

Mike Snitzer Jan. 19, 2019, 6:05 p.m. UTC

Hi,

These mostly stable@ patches will be sent to Linus for 5.0-rc4
inclusion (would've sent today for 5.0-rc3 but I don't yet have
linux-next coverage).

Just wanted to give a heads up because some of the problems fixed
could bite other users of the bio_split()+generic_make_request()
recursive pattern.  We should probably factor out some helpers that
all users could share (e.g. so they don't forget to set
BIO_QUEUE_ENTERED or call trace_block_split(), etc).

Thanks,
Mike

Mike Snitzer (4):
  dm: fix clone_bio() to trigger blk_recount_segments()
  dm: fix redundant IO accounting for bios that need splitting
  dm: fix missing bio_split() pattern code in __split_and_process_bio()
  dm: fix dm_wq_work() to only use __split_and_process_bio() if appropriate

 drivers/md/dm.c | 44 ++++++++++++++++++++++++++++++++------------
 1 file changed, 32 insertions(+), 12 deletions(-)