public inbox for linux-scsi@vger.kernel.org
 help / color / mirror / Atom feed
From: Asutosh Das <asutoshd@codeaurora.org>
To: cang@codeaurora.org, martin.petersen@oracle.com,
	linux-scsi@vger.kernel.org
Cc: Asutosh Das <asutoshd@codeaurora.org>, linux-arm-msm@vger.kernel.org
Subject: [PATCH v5 0/2] Enable power management for ufs wlun
Date: Tue, 23 Feb 2021 21:13:53 -0800	[thread overview]
Message-ID: <cover.1614142928.git.asutoshd@codeaurora.org> (raw)

This patch attempts to fix a deadlock in ufs while sending SSU.
Recently, blk_queue_enter() added a check to not process requests if the
queue is suspended. That leads to a resume of the associated device which
is suspended. In ufs, that device is ufs device wlun and it's parent is
ufs_hba. This resume tries to resume ufs device wlun which in turn tries
to resume ufs_hba, which is already in the process of suspending, thus
causing a deadlock.

This patch takes care of:
* Suspending the ufs device lun only after all other luns are suspended
* Sending SSU during ufs device wlun suspend
* Clearing uac for rpmb and ufs device wlun
* Not sending commands to the device during host suspend

v4 -> v5:
- Addressed Adrian's comments
  * Used the rpmb driver contributed by Adrian
  * Runtime-resume the ufs device during suspend to honor spm-lvl
  * Unregister the scsi_driver in ufshcd_remove()
  * Currently shutdown() puts the ufs device to power-down mode
    so, just removed ufshcd_pci_poweroff()
  * Quiesce the scsi device during shutdown instead of remove

v3 RFC -> v4:
- Addressed Bart's comments
  * Except that I didn't get any checkpatch failures
- Addressed Avri's comments
- Addressed Adrian's comments
  * Added a check for deepsleep power mode
  * Removed a couple of forward declarations
  * Didn't separate the scsi drivers because in rpmb case it just sends uac
    in resume and it seemed pretty neat to me.
- Added sysfs changes to resume the devices before accessing

Asutosh Das (2):
  scsi: ufs: Enable power management for wlun
  ufs: sysfs: Resume the proper scsi device

 drivers/scsi/ufs/ufs-qcom.c      |   2 +
 drivers/scsi/ufs/ufs-sysfs.c     |  26 ++-
 drivers/scsi/ufs/ufshcd-pci.c    |  24 --
 drivers/scsi/ufs/ufshcd-pltfrm.c |  29 +++
 drivers/scsi/ufs/ufshcd-pltfrm.h |   4 +
 drivers/scsi/ufs/ufshcd.c        | 491 +++++++++++++++++++++++++++++++--------
 drivers/scsi/ufs/ufshcd.h        |   5 +
 include/trace/events/ufs.h       |  20 ++
 8 files changed, 469 insertions(+), 132 deletions(-)

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.


             reply	other threads:[~2021-02-24  5:14 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-24  5:13 Asutosh Das [this message]
2021-02-24  5:13 ` [PATCH v5 1/2] scsi: ufs: Enable power management for wlun Asutosh Das
2021-02-24 14:34   ` Adrian Hunter
2021-02-24 18:46     ` Asutosh Das
2021-02-24  5:13 ` [PATCH v5 2/2] ufs: sysfs: Resume the proper scsi device Asutosh Das

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=cover.1614142928.git.asutoshd@codeaurora.org \
    --to=asutoshd@codeaurora.org \
    --cc=cang@codeaurora.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=martin.petersen@oracle.com \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox