On Tue, Jul 31 2018 at 6:49am -0400, Ming Lei <ming.lei@xxxxxxxxxx> wrote: > Hi, > > This patchset fixes one issue related with physical segment computation, > which is found by Mike. In case of dm-rq, the warning of 'blk_cloned_rq_check_limits: > over max segments limit' can be triggered easily. > > Follows the cause: > > 1) in IO fast path(blk_queue_split()), we always figure out physical segment number > no matter the flag of QUEUE_FLAG_NO_SG_MERGE is set or not. > > 2) only blk_recount_segments() and blk_recalc_rq_segments() uses the flag of > QUEUE_FLAG_NO_SG_MERGE, but the two are only called in some unusual > cases, such as request clone in dm-rq. > > 3) the above two computation don't match, and cause the warning of > "blk_cloned_rq_check_limits: over max segments limit". > > This patchset fixes this issue by killing the queue flag since it is basically > bypassed since v4.4, and no one complains that at all. Also multipage bvec will > come soon, and it doesn't make sense to keep QUEUE_FLAG_NO_SG_MERGE any more. Thanks Ming, for the series: Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
