From: Can Guo <cang@codeaurora.org>
To: Bean Huo <huobean@gmail.com>
Cc: alim.akhtar@samsung.com, avri.altman@wdc.com,
asutoshd@codeaurora.org, jejb@linux.ibm.com,
martin.petersen@oracle.com, stanley.chu@mediatek.com,
beanhuo@micron.com, bvanassche@acm.org, tomas.winkler@intel.com,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
rjw@rjwysocki.net
Subject: Re: [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown
Date: Tue, 05 Jan 2021 09:10:05 +0800 [thread overview]
Message-ID: <bf5b8bc409af22f32c4fc5f5de769058@codeaurora.org> (raw)
In-Reply-To: <20201224172010.10701-4-huobean@gmail.com>
On 2020-12-25 01:20, Bean Huo wrote:
> From: Bean Huo <beanhuo@micron.com>
>
> After ufshcd_shutdown(), both UFS device and UFS LINk are powered off,
> return '0' will mislead the upper PM layer since the device has not
> been
> successfully resumed yet. This will let pm_runtime_get_sync() caller
> mistakenly believe the device/LINK has been resumed, which leads to
> request processing timeout that was en-queued later.
>
> To fix this, let ufshcd_system/runtimie_resume() return -EBUSY in case
> of
> hba->is_powered == false.
This change won't work as you expect...
During/after shutdown, for UFS's case only,
pm_runtime_get_sync(hba->dev) will most likely return 0,
because it is already RUNTIME_ACTIVE, pm_runtime_get_sync()
will directly return 0... meaning your change won't even be
exercised.
Check Stanley's change -
https://lore.kernel.org/patchwork/patch/1341389/
Can Guo.
>
> Signed-off-by: Bean Huo <beanhuo@micron.com>
> ---
> drivers/scsi/ufs/ufshcd.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index e221add25a7e..e1bcac51c01f 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -8950,14 +8950,16 @@ int ufshcd_system_resume(struct ufs_hba *hba)
> return -EINVAL;
> }
>
> - if (!hba->is_powered || pm_runtime_suspended(hba->dev))
> + if (!hba->is_powered || pm_runtime_suspended(hba->dev)) {
> /*
> * Let the runtime resume take care of resuming
> * if runtime suspended.
> */
> + ret = -EBUSY;
> goto out;
> - else
> + } else {
> ret = ufshcd_resume(hba, UFS_SYSTEM_PM);
> + }
> out:
> trace_ufshcd_system_resume(dev_name(hba->dev), ret,
> ktime_to_us(ktime_sub(ktime_get(), start)),
> @@ -9026,10 +9028,12 @@ int ufshcd_runtime_resume(struct ufs_hba *hba)
> if (!hba)
> return -EINVAL;
>
> - if (!hba->is_powered)
> + if (!hba->is_powered) {
> + ret = -EBUSY;
> goto out;
> - else
> + } else {
> ret = ufshcd_resume(hba, UFS_RUNTIME_PM);
> + }
> out:
> trace_ufshcd_runtime_resume(dev_name(hba->dev), ret,
> ktime_to_us(ktime_sub(ktime_get(), start)),
prev parent reply other threads:[~2021-01-05 1:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-24 17:20 [PATCH v2 0/3] Two changes of UFS sysfs Bean Huo
2020-12-24 17:20 ` [PATCH v2 1/3] scsi: ufs: Replace sprintf and snprintf with sysfs_emit Bean Huo
2020-12-24 17:20 ` [PATCH v2 2/3] scsi: ufs: Add handling of the return value of pm_runtime_get_sync() Bean Huo
2020-12-28 1:50 ` Can Guo
2021-01-04 17:39 ` Bean Huo
2020-12-24 17:20 ` [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown Bean Huo
2021-01-04 19:26 ` Bean Huo
2021-01-05 1:10 ` Can Guo [this message]
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