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@xxxxxxxxxxxxxx>
---
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!hba there, they are outdated.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@xxxxxxxxxxxx>
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.
