Re: [PATCH 4/5] block: move queue enter logic into blk_mq_submit_bio()

[Ming Lei <ming.lei@redhat.com>]

On Thu, Nov 11, 2021 at 01:58:38PM +0100, Geert Uytterhoeven wrote:
> 	Hi Jens,
> 
> 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@lst.de>
> > > > 
> > > > 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@lst.de/T/#m759b88fda094a65ebf29bc81b780967cdaf9cf28

Maybe you can try the above patch.

Thanks,
Ming