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: Thu, 24 Jun 2021 10:23:01 +0800 [thread overview]
Message-ID: <d9db00ef6dd4b28d0ba2019dcf026479@codeaurora.org> (raw)
In-Reply-To: <89a3c8bf-bbfc-4a2a-73f0-a0db956fbf0e@acm.org>
Hi Bart,
On 2021-06-24 05:51, Bart Van Assche wrote:
> On 6/23/21 12:35 AM, Can Guo wrote:
>> +int ufshcd_get_user_access(struct ufs_hba *hba)
>> +__acquires(&hba->host_sem)
>> +{
>> + down(&hba->host_sem);
>> + if (!ufshcd_is_user_access_allowed(hba)) {
>> + up(&hba->host_sem);
>> + return -EBUSY;
>> + }
>> + if (ufshcd_rpm_get_sync(hba)) {
>> + ufshcd_rpm_put_sync(hba);
>> + up(&hba->host_sem);
>> + return -EBUSY;
>> + }
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(ufshcd_get_user_access);
>> +
>> +void ufshcd_put_user_access(struct ufs_hba *hba)
>> +__releases(&hba->host_sem)
>> +{
>> + ufshcd_rpm_put_sync(hba);
>> + up(&hba->host_sem);
>> +}
>> +EXPORT_SYMBOL_GPL(ufshcd_put_user_access);
>
> Please indent __acquires() and __releases() annotations by one tab as
> is
> done elsewhere in the kernel.
OK.
>
>> static inline bool ufshcd_is_user_access_allowed(struct ufs_hba *hba)
>> {
>> - return !hba->shutting_down;
>> + return !hba->shutting_down && !hba->is_sys_suspended &&
>> + !hba->is_wlu_sys_suspended &&
>> + hba->ufshcd_state == UFSHCD_STATE_OPERATIONAL;
>> }
>
> Is my understanding of the following correct?
> - ufshcd_is_user_access_allowed() is not in the hot path and hence
> should not be inline.
OK.
> - The hba->shutting_down member variable is set from inside a shutdown
> callback. Hence, the hba->shutting_down test can be left out since
> no UFS sysfs attributes are accessed after shutdown has started.
We see that user can still access UFS sysfs during shutdown if shutdown
is invoked by: reboot -f, hence the check.
> - 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.
> - If the HBA is not in an operational state, user space accesses
> should be blocked until error handling has finished. After error
> handling has finished, the user space access should fail if and only
> if error handling failed.
>
Yes, which is why ufshcd_get_user_access() acquires host_sem first and
checks the OPERATOINAL flag here. host_sem shall make sure that user
space accesses should be blocked until error handling has finished.
Thanks,
Can Guo.
> Thanks,
>
> Bart.
next prev parent reply other threads:[~2021-06-24 2:23 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 [this message]
2021-06-24 22:25 ` Bart Van Assche
2021-06-28 7:16 ` Can Guo
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=d9db00ef6dd4b28d0ba2019dcf026479@codeaurora.org \
--to=cang@codeaurora.org \
--cc=adrian.hunter@intel.com \
--cc=alim.akhtar@samsung.com \
--cc=asutoshd@codeaurora.org \
--cc=avri.altman@wdc.com \
--cc=beanhuo@micron.com \
--cc=bvanassche@acm.org \
--cc=gustavoars@kernel.org \
--cc=hongwus@codeaurora.org \
--cc=jaegeuk@kernel.org \
--cc=jejb@linux.ibm.com \
--cc=keosung.park@samsung.com \
--cc=kernel-team@android.com \
--cc=kwmad.kim@samsung.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=nguyenb@codeaurora.org \
--cc=satyat@google.com \
--cc=stanley.chu@mediatek.com \
--cc=ziqichen@codeaurora.org \
/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;
as well as URLs for NNTP newsgroup(s).