All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Saravana Kannan <saravanak@google.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	"James E . J . Bottomley" <jejb@linux.ibm.com>,
	"open list:TARGET SUBSYSTEM" <linux-scsi@vger.kernel.org>,
	Avri Altman <avri.altman@wdc.com>, Bean Huo <huobean@gmail.com>,
	Can Guo <cang@codeaurora.org>,
	Asutosh Das <asutoshd@codeaurora.org>,
	Bart Van Assche <bvanassche@acm.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe
Date: Thu, 8 Jul 2021 14:31:13 +0200	[thread overview]
Message-ID: <CAJZ5v0hfEE=ney1tH5MtQm0KWs4U2yzy_DqAAW7hTyxxx2-cNg@mail.gmail.com> (raw)
In-Reply-To: <66130101-b0c5-a9a3-318a-468c6f3b380f@intel.com>

On Wed, Jul 7, 2021 at 7:49 PM Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> On 7/07/21 8:39 pm, Greg Kroah-Hartman wrote:
> > On Wed, Jul 07, 2021 at 08:29:48PM +0300, Adrian Hunter wrote:
> >> If a LUN fails to probe (e.g. absent BOOT WLUN), the device will not have
> >> been registered but can still have a device link holding a reference to the
> >> device. The unwanted device link will prevent runtime suspend indefinitely,
> >> and cause some warnings if the supplier is ever deleted (e.g. by unbinding
> >> the UFS host controller). Fix by explicitly deleting the device link when
> >> SCSI destroys the SCSI device.
> >>
> >> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> >> ---
> >>  drivers/scsi/ufs/ufshcd.c | 7 +++++++
> >>  1 file changed, 7 insertions(+)
> >>
> >> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> >> index 708b3b62fc4d..483aa74fe2c8 100644
> >> --- a/drivers/scsi/ufs/ufshcd.c
> >> +++ b/drivers/scsi/ufs/ufshcd.c
> >> @@ -5029,6 +5029,13 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev)
> >>              spin_lock_irqsave(hba->host->host_lock, flags);
> >>              hba->sdev_ufs_device = NULL;
> >>              spin_unlock_irqrestore(hba->host->host_lock, flags);
> >> +    } else {
> >> +            /*
> >> +             * If a LUN fails to probe (e.g. absent BOOT WLUN), the device
> >> +             * will not have been registered but can still have a device
> >> +             * link holding a reference to the device.
> >> +             */
> >> +            device_links_scrap(&sdev->sdev_gendev);
> >
> > What created that link?  And why did it do that before probe happened
> > successfully?
>
> The same driver created the link.
>
> The documentation seems to say it is allowed to, if it is the consumer.
> From Documentation/driver-api/device_link.rst
>
>   Usage
>   =====
>
>   The earliest point in time when device links can be added is after
>   :c:func:`device_add()` has been called for the supplier and
>   :c:func:`device_initialize()` has been called for the consumer.

Yes, this is allowed, but if you've added device links to a device
object that is not going to be registered after all, you are
responsible for doing the cleanup.

Why can't you call device_link_del() directly on those links?

Or device_link_remove() if you don't want to deal with link pointers?

  reply	other threads:[~2021-07-08 12:31 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-07 17:29 [PATCH RFC 0/2] driver core: Add ability to delete device links of unregistered devices Adrian Hunter
2021-07-07 17:29 ` [PATCH RFC 1/2] " Adrian Hunter
2021-07-07 17:38   ` Greg Kroah-Hartman
2021-07-07 17:29 ` [PATCH RFC 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe Adrian Hunter
2021-07-07 17:39   ` Greg Kroah-Hartman
2021-07-07 17:49     ` Adrian Hunter
2021-07-08 12:31       ` Rafael J. Wysocki [this message]
2021-07-08 14:17         ` Adrian Hunter
2021-07-08 15:03           ` Rafael J. Wysocki
2021-07-08 15:12             ` Rafael J. Wysocki
2021-07-08 16:02               ` Adrian Hunter
2021-07-08 16:45           ` Saravana Kannan
2021-07-08 16:48             ` Rafael J. Wysocki
2021-07-08 16:57               ` Saravana Kannan
2021-07-08 17:39                 ` Rafael J. Wysocki
2021-07-07 17:40 ` [PATCH RFC 0/2] driver core: Add ability to delete device links of unregistered devices Greg Kroah-Hartman
2021-07-07 17:41   ` Saravana Kannan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAJZ5v0hfEE=ney1tH5MtQm0KWs4U2yzy_DqAAW7hTyxxx2-cNg@mail.gmail.com' \
    --to=rafael@kernel.org \
    --cc=adrian.hunter@intel.com \
    --cc=asutoshd@codeaurora.org \
    --cc=avri.altman@wdc.com \
    --cc=bvanassche@acm.org \
    --cc=cang@codeaurora.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=huobean@gmail.com \
    --cc=jejb@linux.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=martin.petersen@oracle.com \
    --cc=saravanak@google.com \
    --subject='Re: [PATCH RFC 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.