On Thu, Nov 11, 2021 at 03:17:27PM -0700, Jens Axboe wrote: > On 11/11/21 8:23 AM, Ming Lei wrote: > > Hi Geert, > > > > On Thu, Nov 11, 2021 at 03:51:28PM +0100, Geert Uytterhoeven wrote: > >> Hi Ming, > >> > >> On Thu, Nov 11, 2021 at 2:45 PM Ming Lei <ming.lei@xxxxxxxxxx> wrote: > >>> On Thu, Nov 11, 2021 at 01:58:38PM +0100, Geert Uytterhoeven wrote: > >>>> On Thu, 4 Nov 2021, Jens Axboe wrote: > >>>>> On 11/4/21 1:04 PM, Christoph Hellwig wrote: > >>>>>> On Thu, Nov 04, 2021 at 01:02:54PM -0600, Jens Axboe wrote: > >>>>>>> On 11/4/21 12:52 PM, Christoph Hellwig wrote: > >>>>>>>> Looks good: > >>>>>>>> > >>>>>>>> Reviewed-by: Christoph Hellwig <hch@xxxxxx> > >>>>>>> > >>>>>>> So these two are now: > >>>>>>> > >>>>>>> https://git.kernel.dk/cgit/linux-block/commit/?h=for-5.16/block&id=c98cb5bbdab10d187aff9b4e386210eb2332af96 > >>>>>>> > >>>>>>> which is the one I sent here, and then the next one gets cleaned up to > >>>>>>> remove that queue enter helper: > >>>>>>> > >>>>>>> https://git.kernel.dk/cgit/linux-block/commit/?h=for-5.16/block&id=7f930eb31eeb07f1b606b3316d8ad3ab6a92905b > >>>>>>> > >>>>>>> Can I add your reviewed-by to this last one as well? Only change is the > >>>>>>> removal of blk_mq_enter_queue() and the weird construct there, it's just > >>>>>>> bio_queue_enter() now. > >>>>>> > >>>>>> Sure. > >>>>> > >>>>> Thanks, prematurely already done, as you could tell :-) > >>>> > >>>> The updated version is now commit 900e080752025f00 ("block: move queue > >>>> enter logic into blk_mq_submit_bio()") in Linus' tree. > >>>> > >>>> I have bisected failures on m68k/atari (on ARAnyM, using nfhd as the > >>>> root device) to this commit, e.g.: > >>>> > >>>> sd 0:0:0:0: [sda] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s > >>>> sd 0:0:0:0: [sda] tag#0 Sense Key : Illegal Request [current] > >>>> sd 0:0:0:0: [sda] tag#0 Add. Sense: Invalid field in cdb > >>>> sd 0:0:0:0: [sda] tag#0 CDB: Write(10) 2a 08 00 00 00 01 00 00 08 00 > >>>> critical target error, dev sda, sector 1 op 0x1:(WRITE) flags 0x20800 phys_seg 1 prio class 0 > >>>> Buffer I/O error on dev sda1, logical block 0, lost sync page write > >>>> > >>>> EXT4-fs (sda1): I/O error while writing superblock > >>>> sd 0:0:0:0: [sda] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s > >>>> sd 0:0:0:0: [sda] tag#0 Sense Key : Illegal Request [current] > >>>> sd 0:0:0:0: [sda] tag#0 Add. Sense: Invalid field in cdb > >>>> sd 0:0:0:0: [sda] tag#0 CDB: Write(10) 2a 08 00 00 00 01 00 00 08 00 > >>>> critical target error, dev sda, sector 1 op 0x1:(WRITE) flags 0x20800 phys_seg 1 prio class 0 > >>>> Buffer I/O error on dev sda1, logical block 0, lost sync page write > >>>> EXT4-fs (sda1): I/O error while writing superblock > >>>> > >>>> This may happen either when mounting the root file system (leading to an > >>>> unable to mount root fs panic), or later (leading to a read-only > >>>> rootfs). > >>> > >>> BTW, today I just found that hang in blk_mq_freeze_queue_wait() is > >>> caused by commit 900e080752025f00, and the following patch can fix it: > >>> > >>> - blk-mq: don't grab ->q_usage_counter in blk_mq_sched_bio_merge > >>> > >>> https://lore.kernel.org/linux-block/20211111085650.GA476@xxxxxx/T/#m759b88fda094a65ebf29bc81b780967cdaf9cf28 > >>> > >>> Maybe you can try the above patch. > >> > >> Thanks! I have applied both patches, but it doesn't make a difference. > > > > Thanks for your test! > > > > Can you try the following patch? > > > > > > diff --git a/block/blk-mq.c b/block/blk-mq.c > > index f511db395c7f..a5ab2f2e9f67 100644 > > --- a/block/blk-mq.c > > +++ b/block/blk-mq.c > > @@ -2517,7 +2517,6 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q, > > struct blk_mq_alloc_data data = { > > .q = q, > > .nr_tags = 1, > > - .cmd_flags = bio->bi_opf, > > }; > > struct request *rq; > > > > @@ -2525,6 +2524,7 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q, > > return NULL; > > if (unlikely(!submit_bio_checks(bio))) > > goto put_exit; > > + data.cmd_flags = bio->bi_opf; > > if (blk_mq_attempt_bio_merge(q, bio, nsegs, same_queue_rq)) > > goto put_exit; > > That's definitely a real fix, akin to the other pre-enter variants, this > one just post checks. Geert, can you give this a whirl? > > Ming, would you mind sending this as a real patch? Hi Jens, The above patch may not be enough, since submit_bio_checks() is done in case of using cached request, so how about the following patch(un-tested)? diff --git a/block/blk-mq.c b/block/blk-mq.c index f511db395c7f..f84044c8de3f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2517,7 +2517,6 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q, struct blk_mq_alloc_data data = { .q = q, .nr_tags = 1, - .cmd_flags = bio->bi_opf, }; struct request *rq; @@ -2525,6 +2524,7 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q, return NULL; if (unlikely(!submit_bio_checks(bio))) goto put_exit; + data.cmd_flags = bio->bi_opf; if (blk_mq_attempt_bio_merge(q, bio, nsegs, same_queue_rq)) goto put_exit; @@ -2564,13 +2564,15 @@ static inline struct request *blk_mq_get_request(struct request_queue *q, if (blk_mq_attempt_bio_merge(q, bio, nsegs, same_queue_rq)) return NULL; + if (bio->bi_opf != rq->cmd_flags) + goto fallback; plug->cached_rq = rq_list_next(rq); INIT_LIST_HEAD(&rq->queuelist); rq_qos_throttle(q, bio); return rq; } } - +fallback: return blk_mq_get_new_requests(q, plug, bio, nsegs, same_queue_rq); } -- Ming
