On Thu, Feb 02, 2017 at 09:06:13AM -0700, Jens Axboe wrote: > If we end up doing a request-to-request merge when we have completed > a bio-to-request merge, we free the request from deep down in that > path. For blk-mq-sched, the merge path has to hold the appropriate > lock, but we don't need it for freeing the request. And in fact > holding the lock is problematic, since we are now calling the > mq sched put_rq_private() hook with the lock held. Other call paths > do not hold this lock. > > Fix this inconsistency by ensuring that the caller frees a merged > request. Then we can do it outside of the lock, making it both more > efficient and fixing the blk-mq-sched problem of invoking parts of > the scheduler with an unknown lock state. > > Reported-by: Paolo Valente <paolo.valente@xxxxxxxxxx> Reviewed-by: Omar Sandoval <osandov@xxxxxx> > Signed-off-by: Jens Axboe <axboe@xxxxxx> > --- > block/blk-core.c | 12 +++++++++--- > block/blk-merge.c | 15 ++++++++++++--- > block/blk-mq-sched.c | 9 ++++++--- > block/blk-mq-sched.h | 3 ++- > block/mq-deadline.c | 8 ++++++-- > 5 files changed, 35 insertions(+), 12 deletions(-)
