| Message ID | 20210302190552.715551440@debian-a64.vm (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/4] block: introduce a function submit_bio_noacct_mq_direct | expand |
On 3/3/21 3:05 AM, Mikulas Patocka wrote: > Don't clear REQ_HIPRI for bio-based drivers. Device mapper will need to > see this flag in order to support polling. > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > > --- > block/blk-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-2.6/block/blk-core.c > =================================================================== > --- linux-2.6.orig/block/blk-core.c 2021-03-02 10:43:28.000000000 +0100 > +++ linux-2.6/block/blk-core.c 2021-03-02 10:53:50.000000000 +0100 I notice that the diff header indicates that the code base is from linux-2.6. Or it's just the name of your directory, while the code base is for the latest upstream 5.12? > @@ -836,7 +836,7 @@ static noinline_for_stack bool submit_bi > } > } > > - if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) > + if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && !bdev->bd_disk->fops->submit_bio) > bio->bi_opf &= ~REQ_HIPRI; > > switch (bio_op(bio)) { > > -- What if dm device is built upon mq devices that are not capable of polling, i.e., mq devices without QUEUE_FLAG_POLL set? Then this dm device shall not support polling.
On Wed, 3 Mar 2021, JeffleXu wrote: > > > On 3/3/21 3:05 AM, Mikulas Patocka wrote: > > Don't clear REQ_HIPRI for bio-based drivers. Device mapper will need to > > see this flag in order to support polling. > > > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > > > > --- > > block/blk-core.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > Index: linux-2.6/block/blk-core.c > > =================================================================== > > --- linux-2.6.orig/block/blk-core.c 2021-03-02 10:43:28.000000000 +0100 > > +++ linux-2.6/block/blk-core.c 2021-03-02 10:53:50.000000000 +0100 > > I notice that the diff header indicates that the code base is from > linux-2.6. Or it's just the name of your directory, while the code base > is for the latest upstream 5.12? It's just the name of the git repository. The patch is against 5.12-rc1. > > > @@ -836,7 +836,7 @@ static noinline_for_stack bool submit_bi > > } > > } > > > > - if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) > > + if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && !bdev->bd_disk->fops->submit_bio) > > bio->bi_opf &= ~REQ_HIPRI; > > > > switch (bio_op(bio)) { > > > > -- > > What if dm device is built upon mq devices that are not capable of > polling, i.e., mq devices without QUEUE_FLAG_POLL set? Then this dm > device shall not support polling. We will check if the underlying queue has QUEUE_FLAG_POLL in __map_bio - see this piece of code: case DM_MAPIO_REMAPPED: /* the bio has been remapped so dispatch it */ trace_block_bio_remap(clone, bio_dev(io->orig_bio), sector); if (clone->bi_opf & REQ_HIPRI && test_bit(QUEUE_FLAG_POLL, &clone->bi_bdev->bd_disk->queue->queue_flags)) { ci->poll_queue = clone->bi_bdev->bd_disk->queue; ci->poll_cookie = submit_bio_noacct_mq_direct(clone); } else { ci->poll_cookie = BLK_QC_T_NONE; submit_bio_noacct(clone); } break; Mikulas
Index: linux-2.6/block/blk-core.c =================================================================== --- linux-2.6.orig/block/blk-core.c 2021-03-02 10:43:28.000000000 +0100 +++ linux-2.6/block/blk-core.c 2021-03-02 10:53:50.000000000 +0100 @@ -836,7 +836,7 @@ static noinline_for_stack bool submit_bi } } - if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) + if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && !bdev->bd_disk->fops->submit_bio) bio->bi_opf &= ~REQ_HIPRI; switch (bio_op(bio)) {
Don't clear REQ_HIPRI for bio-based drivers. Device mapper will need to see this flag in order to support polling. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> --- block/blk-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)