| Message ID | 1609479893-8889-2-git-send-email-cang@codeaurora.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Synchronize user layer access with system PM ops and error handling | expand |
On 12/31/20 9:44 PM, Can Guo wrote: > During system resume/suspend, hba could be NULL. In this case, do not touch > eh_sem. > > Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM events and async scan") > > Signed-off-by: Can Guo <cang@codeaurora.org> > --- > drivers/scsi/ufs/ufshcd.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > index e221add..34e2541 100644 > --- a/drivers/scsi/ufs/ufshcd.c > +++ b/drivers/scsi/ufs/ufshcd.c > @@ -8896,8 +8896,11 @@ int ufshcd_system_suspend(struct ufs_hba *hba) > int ret = 0; > ktime_t start = ktime_get(); > > + if (!hba) > + return 0; > + > down(&hba->eh_sem); > - if (!hba || !hba->is_powered) > + if (!hba->is_powered) > return 0; > > if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) == > @@ -8945,10 +8948,8 @@ int ufshcd_system_resume(struct ufs_hba *hba) > int ret = 0; > ktime_t start = ktime_get(); > > - if (!hba) { > - up(&hba->eh_sem); > + if (!hba) > return -EINVAL; > - } > > if (!hba->is_powered || pm_runtime_suspended(hba->dev)) > /* Hi Can, How can ufshcd_system_suspend() or ufshcd_system_resume() be called with a NULL argument? In ufshcd_pci_probe() I see that pci_set_drvdata() is called before pm_runtime_allow(). ufshcd_pci_remove() calls pm_runtime_forbid(). Thanks, Bart.
On 2021-01-02 00:05, Bart Van Assche wrote: > On 12/31/20 9:44 PM, Can Guo wrote: >> During system resume/suspend, hba could be NULL. In this case, do not >> touch >> eh_sem. >> >> Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM >> events and async scan") >> >> Signed-off-by: Can Guo <cang@codeaurora.org> >> --- >> drivers/scsi/ufs/ufshcd.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >> index e221add..34e2541 100644 >> --- a/drivers/scsi/ufs/ufshcd.c >> +++ b/drivers/scsi/ufs/ufshcd.c >> @@ -8896,8 +8896,11 @@ int ufshcd_system_suspend(struct ufs_hba *hba) >> int ret = 0; >> ktime_t start = ktime_get(); >> >> + if (!hba) >> + return 0; >> + >> down(&hba->eh_sem); >> - if (!hba || !hba->is_powered) >> + if (!hba->is_powered) >> return 0; >> >> if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) == >> @@ -8945,10 +8948,8 @@ int ufshcd_system_resume(struct ufs_hba *hba) >> int ret = 0; >> ktime_t start = ktime_get(); >> >> - if (!hba) { >> - up(&hba->eh_sem); >> + if (!hba) >> return -EINVAL; >> - } >> >> if (!hba->is_powered || pm_runtime_suspended(hba->dev)) >> /* > > Hi Can, > > How can ufshcd_system_suspend() or ufshcd_system_resume() be called > with a > NULL argument? In ufshcd_pci_probe() I see that pci_set_drvdata() is > called > before pm_runtime_allow(). ufshcd_pci_remove() calls > pm_runtime_forbid(). > > Thanks, > > Bart. Hi Bart, You are right about ufshcd_RUNTIME_suspend/resume() - platform_set_drvdata() is called before pm_runtime_enable(), so runtime suspend/resume cannot happen before pm_runtime_enable() is called. We can remove the sanity checks of !hba there, they are outdated. But for ufshcd_SYSTEM_suspend/resume() callbacks (not runtime ones), my understanding is that system suspend/resume may happen after probe (vendor driver probe calls ufshcd_pltfrm_init()) starts but before platform_set_drvdata() is called, in this case hba is NULL. int ufshcd_pltfrm_init(struct platform_device *pdev, const struct ufs_hba_variant_ops *vops) { ... platform_set_drvdata(pdev, hba); pm_runtime_set_active(&pdev->dev); pm_runtime_enable(&pdev->dev); } Thanks, Can Guo.
On 2021-01-02 20:29, Can Guo wrote: > On 2021-01-02 00:05, Bart Van Assche wrote: >> On 12/31/20 9:44 PM, Can Guo wrote: >>> During system resume/suspend, hba could be NULL. In this case, do not >>> touch >>> eh_sem. >>> >>> Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM >>> events and async scan") >>> >>> Signed-off-by: Can Guo <cang@codeaurora.org> >>> --- >>> drivers/scsi/ufs/ufshcd.c | 9 +++++---- >>> 1 file changed, 5 insertions(+), 4 deletions(-) >>> >>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >>> index e221add..34e2541 100644 >>> --- a/drivers/scsi/ufs/ufshcd.c >>> +++ b/drivers/scsi/ufs/ufshcd.c >>> @@ -8896,8 +8896,11 @@ int ufshcd_system_suspend(struct ufs_hba *hba) >>> int ret = 0; >>> ktime_t start = ktime_get(); >>> >>> + if (!hba) >>> + return 0; >>> + >>> down(&hba->eh_sem); >>> - if (!hba || !hba->is_powered) >>> + if (!hba->is_powered) >>> return 0; >>> >>> if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) == >>> @@ -8945,10 +8948,8 @@ int ufshcd_system_resume(struct ufs_hba *hba) >>> int ret = 0; >>> ktime_t start = ktime_get(); >>> >>> - if (!hba) { >>> - up(&hba->eh_sem); >>> + if (!hba) >>> return -EINVAL; >>> - } >>> >>> if (!hba->is_powered || pm_runtime_suspended(hba->dev)) >>> /* >> >> Hi Can, >> >> How can ufshcd_system_suspend() or ufshcd_system_resume() be called >> with a >> NULL argument? In ufshcd_pci_probe() I see that pci_set_drvdata() is >> called >> before pm_runtime_allow(). ufshcd_pci_remove() calls >> pm_runtime_forbid(). >> >> Thanks, >> >> Bart. > > Hi Bart, > > You are right about ufshcd_RUNTIME_suspend/resume() - > platform_set_drvdata() > is called before pm_runtime_enable(), so runtime suspend/resume cannot > happen > before pm_runtime_enable() is called. We can remove the sanity checks > of > !hba there, they are outdated. Add more history here - before Stanley's change (see below), platform_set_drvdata() is called AFTER pm_runtime_enable(), which was why we needed sanity checks of !hba. But now the sanity checks are unnecessary in ufshcd_RUNTIME_suspend/resume(), so feel free to remove them. But still, things are a bit different for ufshcd_SYSTEM_suspend/resume(), we need the sanity checks of !hba there if my understanding is correct. commit 24e2e7a19f7e4b83d0d5189040d997bce3596473 Author: Stanley Chu <stanley.chu@mediatek.com> Date: Wed Jun 12 23:19:05 2019 +0800 scsi: ufs: Avoid runtime suspend possibly being blocked forever Thanks, Can Guo. > > But for ufshcd_SYSTEM_suspend/resume() callbacks (not runtime ones), my > understanding is that system suspend/resume may happen after probe > (vendor > driver probe calls ufshcd_pltfrm_init()) starts but before > platform_set_drvdata() > is called, in this case hba is NULL. > > int ufshcd_pltfrm_init(struct platform_device *pdev, > const struct ufs_hba_variant_ops *vops) > { > ... > platform_set_drvdata(pdev, hba); > > pm_runtime_set_active(&pdev->dev); > pm_runtime_enable(&pdev->dev); > } > > Thanks, > > Can Guo.
On 2/01/21 3:10 pm, Can Guo wrote: > On 2021-01-02 20:29, Can Guo wrote: >> On 2021-01-02 00:05, Bart Van Assche wrote: >>> On 12/31/20 9:44 PM, Can Guo wrote: >>>> During system resume/suspend, hba could be NULL. In this case, do not touch >>>> eh_sem. >>>> >>>> Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM events >>>> and async scan") >>>> >>>> Signed-off-by: Can Guo <cang@codeaurora.org> >>>> --- >>>> drivers/scsi/ufs/ufshcd.c | 9 +++++---- >>>> 1 file changed, 5 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >>>> index e221add..34e2541 100644 >>>> --- a/drivers/scsi/ufs/ufshcd.c >>>> +++ b/drivers/scsi/ufs/ufshcd.c >>>> @@ -8896,8 +8896,11 @@ int ufshcd_system_suspend(struct ufs_hba *hba) >>>> int ret = 0; >>>> ktime_t start = ktime_get(); >>>> >>>> + if (!hba) >>>> + return 0; >>>> + >>>> down(&hba->eh_sem); >>>> - if (!hba || !hba->is_powered) >>>> + if (!hba->is_powered) >>>> return 0; >>>> >>>> if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) == >>>> @@ -8945,10 +8948,8 @@ int ufshcd_system_resume(struct ufs_hba *hba) >>>> int ret = 0; >>>> ktime_t start = ktime_get(); >>>> >>>> - if (!hba) { >>>> - up(&hba->eh_sem); >>>> + if (!hba) >>>> return -EINVAL; >>>> - } >>>> >>>> if (!hba->is_powered || pm_runtime_suspended(hba->dev)) >>>> /* >>> >>> Hi Can, >>> >>> How can ufshcd_system_suspend() or ufshcd_system_resume() be called with a >>> NULL argument? In ufshcd_pci_probe() I see that pci_set_drvdata() is called >>> before pm_runtime_allow(). ufshcd_pci_remove() calls pm_runtime_forbid(). >>> >>> Thanks, >>> >>> Bart. >> >> Hi Bart, >> >> You are right about ufshcd_RUNTIME_suspend/resume() - platform_set_drvdata() >> is called before pm_runtime_enable(), so runtime suspend/resume cannot happen >> before pm_runtime_enable() is called. We can remove the sanity checks of >> !hba there, they are outdated. > > Add more history here - before Stanley's change (see below), > platform_set_drvdata() > is called AFTER pm_runtime_enable(), which was why we needed sanity checks > of !hba. > But now the sanity checks are unnecessary in > ufshcd_RUNTIME_suspend/resume(), so > feel free to remove them. > > But still, things are a bit different for ufshcd_SYSTEM_suspend/resume(), we > need > the sanity checks of !hba there if my understanding is correct. > > commit 24e2e7a19f7e4b83d0d5189040d997bce3596473 > Author: Stanley Chu <stanley.chu@mediatek.com> > Date: Wed Jun 12 23:19:05 2019 +0800 > > scsi: ufs: Avoid runtime suspend possibly being blocked forever > > Thanks, > Can Guo. > >> >> But for ufshcd_SYSTEM_suspend/resume() callbacks (not runtime ones), my >> understanding is that system suspend/resume may happen after probe (vendor >> driver probe calls ufshcd_pltfrm_init()) starts but before >> platform_set_drvdata() >> is called, in this case hba is NULL. >> >> int ufshcd_pltfrm_init(struct platform_device *pdev, >> const struct ufs_hba_variant_ops *vops) >> { >> ... >> platform_set_drvdata(pdev, hba); >> >> pm_runtime_set_active(&pdev->dev); >> pm_runtime_enable(&pdev->dev); >> } Hi Can I expect probe and system suspend are synchronized e.g. by device_lock(), so hba would not be NULL. Is there any example of it being NULL in system suspend? Regards Adrian
On 2021-01-15 21:07, Adrian Hunter wrote: > On 2/01/21 3:10 pm, Can Guo wrote: >> On 2021-01-02 20:29, Can Guo wrote: >>> On 2021-01-02 00:05, Bart Van Assche wrote: >>>> On 12/31/20 9:44 PM, Can Guo wrote: >>>>> During system resume/suspend, hba could be NULL. In this case, do >>>>> not touch >>>>> eh_sem. >>>>> >>>>> Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM >>>>> events >>>>> and async scan") >>>>> >>>>> Signed-off-by: Can Guo <cang@codeaurora.org> >>>>> --- >>>>> drivers/scsi/ufs/ufshcd.c | 9 +++++---- >>>>> 1 file changed, 5 insertions(+), 4 deletions(-) >>>>> >>>>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >>>>> index e221add..34e2541 100644 >>>>> --- a/drivers/scsi/ufs/ufshcd.c >>>>> +++ b/drivers/scsi/ufs/ufshcd.c >>>>> @@ -8896,8 +8896,11 @@ int ufshcd_system_suspend(struct ufs_hba >>>>> *hba) >>>>> int ret = 0; >>>>> ktime_t start = ktime_get(); >>>>> >>>>> + if (!hba) >>>>> + return 0; >>>>> + >>>>> down(&hba->eh_sem); >>>>> - if (!hba || !hba->is_powered) >>>>> + if (!hba->is_powered) >>>>> return 0; >>>>> >>>>> if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) == >>>>> @@ -8945,10 +8948,8 @@ int ufshcd_system_resume(struct ufs_hba >>>>> *hba) >>>>> int ret = 0; >>>>> ktime_t start = ktime_get(); >>>>> >>>>> - if (!hba) { >>>>> - up(&hba->eh_sem); >>>>> + if (!hba) >>>>> return -EINVAL; >>>>> - } >>>>> >>>>> if (!hba->is_powered || pm_runtime_suspended(hba->dev)) >>>>> /* >>>> >>>> Hi Can, >>>> >>>> How can ufshcd_system_suspend() or ufshcd_system_resume() be called >>>> with a >>>> NULL argument? In ufshcd_pci_probe() I see that pci_set_drvdata() is >>>> called >>>> before pm_runtime_allow(). ufshcd_pci_remove() calls >>>> pm_runtime_forbid(). >>>> >>>> Thanks, >>>> >>>> Bart. >>> >>> Hi Bart, >>> >>> You are right about ufshcd_RUNTIME_suspend/resume() - >>> platform_set_drvdata() >>> is called before pm_runtime_enable(), so runtime suspend/resume >>> cannot happen >>> before pm_runtime_enable() is called. We can remove the sanity checks >>> of >>> !hba there, they are outdated. >> >> Add more history here - before Stanley's change (see below), >> platform_set_drvdata() >> is called AFTER pm_runtime_enable(), which was why we needed sanity >> checks >> of !hba. >> But now the sanity checks are unnecessary in >> ufshcd_RUNTIME_suspend/resume(), so >> feel free to remove them. >> >> But still, things are a bit different for >> ufshcd_SYSTEM_suspend/resume(), we >> need >> the sanity checks of !hba there if my understanding is correct. >> >> commit 24e2e7a19f7e4b83d0d5189040d997bce3596473 >> Author: Stanley Chu <stanley.chu@mediatek.com> >> Date: Wed Jun 12 23:19:05 2019 +0800 >> >> scsi: ufs: Avoid runtime suspend possibly being blocked forever >> >> Thanks, >> Can Guo. >> >>> >>> But for ufshcd_SYSTEM_suspend/resume() callbacks (not runtime ones), >>> my >>> understanding is that system suspend/resume may happen after probe >>> (vendor >>> driver probe calls ufshcd_pltfrm_init()) starts but before >>> platform_set_drvdata() >>> is called, in this case hba is NULL. >>> >>> int ufshcd_pltfrm_init(struct platform_device *pdev, >>> const struct ufs_hba_variant_ops *vops) >>> { >>> ... >>> platform_set_drvdata(pdev, hba); >>> >>> pm_runtime_set_active(&pdev->dev); >>> pm_runtime_enable(&pdev->dev); >>> } > > Hi Can > > I expect probe and system suspend are synchronized e.g. by > device_lock(), so > hba would not be NULL. Is there any example of it being NULL in system > suspend? > > Regards > Adrian Hi Adrian, Thanks for the remind - I didn't notice they are protected by device_lock(). You are right, hba cannot be NULL in current code... Maybe if (!hba) was there just for a sanity check. I will make a change to remove these checks. Thanks, Can Guo.
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index e221add..34e2541 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -8896,8 +8896,11 @@ int ufshcd_system_suspend(struct ufs_hba *hba) int ret = 0; ktime_t start = ktime_get(); + if (!hba) + return 0; + down(&hba->eh_sem); - if (!hba || !hba->is_powered) + if (!hba->is_powered) return 0; if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) == @@ -8945,10 +8948,8 @@ int ufshcd_system_resume(struct ufs_hba *hba) int ret = 0; ktime_t start = ktime_get(); - if (!hba) { - up(&hba->eh_sem); + if (!hba) return -EINVAL; - } if (!hba->is_powered || pm_runtime_suspended(hba->dev)) /*
During system resume/suspend, hba could be NULL. In this case, do not touch eh_sem. Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM events and async scan") Signed-off-by: Can Guo <cang@codeaurora.org> --- drivers/scsi/ufs/ufshcd.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)