From: Can Guo <cang@codeaurora.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: asutoshd@codeaurora.org, nguyenb@codeaurora.org,
hongwus@codeaurora.org, ziqichen@codeaurora.org,
linux-scsi@vger.kernel.org, kernel-team@android.com,
Alim Akhtar <alim.akhtar@samsung.com>,
Avri Altman <avri.altman@wdc.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Bean Huo <beanhuo@micron.com>,
Stanley Chu <stanley.chu@mediatek.com>,
Keoseong Park <keosung.park@samsung.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Jaegeuk Kim <jaegeuk@kernel.org>,
Kiwoong Kim <kwmad.kim@samsung.com>,
Satya Tangirala <satyat@google.com>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 10/10] scsi: ufs: Apply more limitations to user access
Date: Mon, 28 Jun 2021 15:16:52 +0800 [thread overview]
Message-ID: <0c859144bb1570331853d6eaf441fad9@codeaurora.org> (raw)
In-Reply-To: <e803db99-947c-f217-e0c8-091241014086@acm.org>
On 2021-06-25 06:25, Bart Van Assche wrote:
> On 6/23/21 7:23 PM, Can Guo wrote:
>> On 2021-06-24 05:51, Bart Van Assche wrote:
>>> On 6/23/21 12:35 AM, Can Guo wrote:
>>> - During system suspend, user space software is paused before the
>>> device
>>> driver freeze callbacks are invoked. Hence, the
>>> hba->is_sys_suspended
>>> check can be left out.
>>
>> is_sys_suspended indicates that system resume failed (power/clk is
>> OFF).
>>
>>> - If a LUN is runtime suspended, it should be resumed if accessed
>>> from
>>> user space instead of failing user space accesses. In other words,
>>> the
>>> hba->is_wlu_sys_suspended check seems inappropriate to me.
>>
>> hba->is_wlu_sys_suspended indicates that wl system resume failed,
>> device
>> is not operational.
>
> Hi Can,
>
> Thanks for the clarification. How about converting the above two
> answers
> into comments inside ufshcd_is_user_access_allowed()?
>
Sure.
> Should ufshcd_is_user_access_allowed() perhaps be called after
> ufshcd_rpm_get_sync() instead of before to prevent that the value of
> hba->is_sys_suspended or hba->is_wlu_sys_suspended changes after having
> been checked and before the UFS device is accessed?
>
is_sys_suspended and is_wlu_sys_suspended only represent system PM
status,
not runtime PM status.
My understanding is that user threads are frozen before system PM
starts,
so it does not matter we call ufshcd_is_user_access_allowed() before or
after ufshcd_rpm_get_sync().
If my understanding is wrong, then we need to either call
lock_system_sleep()
in get_user_access() or wrap
ufshcd_suspend_prepare/ufshcd_resume_complete()
with host_sem.
Thanks,
Can Guo.
> Thanks,
>
> Bart.
prev parent reply other threads:[~2021-06-28 7:17 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1624433711-9339-1-git-send-email-cang@codeaurora.org>
2021-06-23 7:35 ` [PATCH v4 01/10] scsi: ufs: Rename flags pm_op_in_progress and is_sys_suspended Can Guo
2021-06-23 20:05 ` Bart Van Assche
2021-06-23 20:57 ` Bart Van Assche
2021-06-24 2:02 ` Can Guo
2021-06-24 2:34 ` Can Guo
2021-06-24 6:04 ` Adrian Hunter
2021-06-23 20:42 ` Bjorn Andersson
2021-06-23 22:41 ` Bart Van Assche
2021-06-24 2:04 ` Can Guo
2021-06-24 17:32 ` Bart Van Assche
2021-06-24 23:42 ` Bart Van Assche
2021-06-28 7:01 ` Can Guo
2021-06-28 7:35 ` Can Guo
2021-06-28 17:07 ` Bart Van Assche
2021-06-23 7:35 ` [PATCH v4 02/10] scsi: ufs: Add " Can Guo
2021-06-23 12:33 ` Adrian Hunter
2021-06-24 2:05 ` Can Guo
2021-06-23 20:59 ` Bart Van Assche
2021-06-24 2:07 ` Can Guo
2021-06-24 17:35 ` Bart Van Assche
2021-06-28 7:11 ` Can Guo
2021-06-23 7:35 ` [PATCH v4 03/10] scsi: ufs: Update the return value of supplier pm ops Can Guo
2021-06-23 21:08 ` Bart Van Assche
2021-06-24 2:11 ` Can Guo
2021-06-23 7:35 ` [PATCH v4 04/10] scsi: ufs: Enable IRQ after enabling clocks in error handling preparation Can Guo
2021-06-23 21:20 ` Bart Van Assche
2021-06-23 7:35 ` [PATCH 05/10] scsi: ufs: Complete the cmd before returning in queuecommand Can Guo
2021-06-23 7:39 ` Can Guo
2021-06-23 7:35 ` [PATCH v4 05/10] scsi: ufs: Remove a redundant tag check in ufshcd_queuecommand() Can Guo
2021-06-23 21:24 ` Bart Van Assche
2021-06-23 7:35 ` [PATCH v4 06/10] scsi: ufs: Remove host_sem used in suspend/resume Can Guo
2021-06-23 14:30 ` Adrian Hunter
2021-06-24 2:16 ` Can Guo
2021-06-24 5:52 ` Adrian Hunter
2021-06-24 6:12 ` Can Guo
2021-06-24 6:23 ` Adrian Hunter
2021-06-24 6:31 ` Can Guo
2021-06-24 10:04 ` Adrian Hunter
2021-06-28 7:26 ` Can Guo
2021-07-07 19:04 ` Adrian Hunter
2021-06-24 17:11 ` Bart Van Assche
2021-06-28 8:17 ` Can Guo
2021-06-28 17:31 ` Bart Van Assche
2021-06-29 6:23 ` Can Guo
2021-06-29 18:01 ` Bart Van Assche
2021-06-29 21:50 ` Can Guo
2021-06-23 7:35 ` [PATCH v4 07/10] scsi: ufs: Simplify error handling preparation Can Guo
2021-06-23 21:30 ` Bart Van Assche
2021-06-23 7:35 ` [PATCH v4 08/10] scsi: ufs: Update ufshcd_recover_pm_error() Can Guo
2021-06-23 7:35 ` [PATCH v4 09/10] scsi: ufs: Update the fast abort path in ufshcd_abort() for PM requests Can Guo
2021-06-23 21:33 ` Bart Van Assche
2021-06-24 4:16 ` Can Guo
2021-06-24 16:57 ` Bart Van Assche
2021-06-23 7:35 ` [PATCH v4 10/10] scsi: ufs: Apply more limitations to user access Can Guo
2021-06-23 21:51 ` Bart Van Assche
2021-06-24 2:23 ` Can Guo
2021-06-24 22:25 ` Bart Van Assche
2021-06-28 7:16 ` Can Guo [this message]
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