RE: [PATCH] Revert "blk-mq: issue directly if hw queue isn't busy in case of 'none'"

["Hunter, Adrian" <adrian.hunter@intel.com>]

> -----Original Message-----
> From: Jens Axboe [mailto:axboe@kernel.dk]
> Sent: Tuesday, August 28, 2018 8:12 PM
> To: Ian W MORRISON <ianwmorrison@gmail.com>
> Cc: linux-block@vger.kernel.org; linux-kernel@vger.kernel.org;
> kashyap.desai@broadcom.com; loberman@redhat.com; osandov@fb.com;
> hch@lst.de; bart.vanassche@wdc.com; hare@suse.de;
> ming.lei@redhat.com; Hunter, Adrian <adrian.hunter@intel.com>
> Subject: Re: [PATCH] Revert "blk-mq: issue directly if hw queue isn't busy in
> case of 'none'"
> 
> On 8/28/18 11:01 AM, Ian W MORRISON wrote:
> > On Wed, 29 Aug 2018 at 02:13, Jens Axboe <axboe@kernel.dk> wrote:
> >>
> >> On 8/28/18 10:10 AM, Ian W MORRISON wrote:
> >>> On Wed, 29 Aug 2018 at 02:09, Jens Axboe <axboe@kernel.dk> wrote:
> >>>>
> >>>> On 8/28/18 10:07 AM, Ian W MORRISON wrote:
> >>>>> On Wed, 29 Aug 2018 at 01:48, Jens Axboe <axboe@kernel.dk>
> wrote:
> >>>>>>
> >>>>>> On 8/28/18 9:47 AM, Ian W MORRISON wrote:
> >>>>>>> Kernel oops when booting on Bay and Cherry Trail devices such as
> >>>>>>> Intel Compute Stick. Bisected as:
> >>>>>>>
> >>>>>>> commit 6ce3dd6eec11 ("blk-mq: issue directly if hw queue isn't
> >>>>>>> busy in case of 'none'")
> >>>>>>>
> >>>>>>> This patch reverts the above commit.
> >>>>>>
> >>>>>> Did I miss the posting of that oops? Just curious where this is
> >>>>>> going wrong. Not adverse to reverting, but I'd like to try to
> >>>>>> understand the issue first.
> >>>>>>
> >>>>>> --
> >>>>>> Jens Axboe
> >>>>>>
> >>>>>
> >>>>> I've not been able to capture it however manually transcribing
> >>>>> what is on the screen:
> >>>>>
> >>>>> mmc0: Got data interrupt 0x00000002 even though no data operation
> >>>>>
> >>>>> followed by:
> >>>>>
> >>>>> mmc0: sdhci: ============= SDHCI REGISTER DUMP
> ==============
> >>>>>
> >>>>> Do you want any specific register value or should I transcribe
> >>>>> each (as I am working from an image taken at boot)?
> >>>>
> >>>> Just take a picture of the screen, that should be good enough.
> >>>>
> >>>> --
> >>>> Jens Axboe
> >>>>
> >>>
> >>> Attached as requested.
> >>
> >> Can you see if this patch helps?
> >>
> >> https://marc.info/?l=linux-mmc&m=153485326025301&w=2
> >>
> >> --
> >> Jens Axboe
> >>
> >
> > I confirm that the above patch works with commit 6ce3dd6eec11 and
> > removes the need for reverting it on eMMC based devices.
> >
> > Tested on Bay Trail, Cherry Trail (both now working) and Kaby Lake
> > (not affected) devices.
> 
> Great, thanks for testing. Adrian, when is this going upstream?

It is in Ulf's fixes branch, so most likely v4.19-rc2 .  Then to stable in due course.

	https://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc.git/commit/?h=fixes&id=26caddf274cf1e89fd4ce44ab2b8dbc7a7f97681