On 12/21/2011 07:33 AM, Dan Williams wrote: > Commit 5e081591 "block: warn if tag is greater than real_max_depth" > cleaned up blk_queue_end_tag() to warn when the tag is truly invalid > (greater than real_max_depth). However, it changed behavior in the tag > < max_depth case to not end the request. Leading to triggering of > BUG_ON(blk_queued_rq(rq)) in the request completion path: > > http://marc.info/?l=linux-kernel&m=132204370518629&w=2 > > In order to allow blk_queue_resize_tags() to shrink the tag space > blk_queue_end_tag() must always complete tags with a value less than > real_max_depth regardless of the current max_depth. > > Cc: Tao Ma <boyu.mt@xxxxxxxxxx> > Reported-by: Meelis Roos <mroos@xxxxx> > Reported-by: Ed Nadolski <edmund.nadolski@xxxxxxxxx> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> > --- > Functionally the same as Tao Ma's fix [1], but just moves the warn into the > if() directly. > > [1]: http://marc.info/?l=linux-scsi&m=132439698602441&w=2 > > -- > Dan > > block/blk-tag.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/block/blk-tag.c b/block/blk-tag.c > index e74d6d1..6e61262 100644 > --- a/block/blk-tag.c > +++ b/block/blk-tag.c > @@ -286,12 +286,13 @@ void blk_queue_end_tag(struct request_queue *q, struct request *rq) > > BUG_ON(tag == -1); > > - if (unlikely(tag >= bqt->max_depth)) { > + if (WARN_ONCE(tag >= bqt->real_max_depth, > + "%s: tag %d greater than tag map size: %d\n", > + __func__, tag, bqt->real_max_depth)) { > /* > * This can happen after tag depth has been reduced. Please also change the comments here since it should never happen in the right workload. Thanks Tao > * But tag shouldn't be larger than real_max_depth. > */ > - WARN_ON(tag >= bqt->real_max_depth); > return; > } > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
