[RESEND PATCH v3 0/2] change UIC command handling

Kiwoong Kim posted 2 patches 2 years ago
drivers/ufs/core/ufshcd.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
[RESEND PATCH v3 0/2] change UIC command handling
Posted by Kiwoong Kim 2 years ago
v2 -> v3: rule out the change of polling w/ pmc from this thread.
(I'll post the change later)
v1 -> v2: remove an unused variable in __ufshcd_send_uic_cmd

Kiwoong Kim (2):
  ufs: make __ufshcd_send_uic_cmd not wrapped by host_lock
  ufs: poll HCS.UCRDY before issuing a UIC command

 drivers/ufs/core/ufshcd.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

-- 
2.7.4
Re: [RESEND PATCH v3 0/2] change UIC command handling
Posted by Martin K. Petersen 2 years ago
Kiwoong,

> v2 -> v3: rule out the change of polling w/ pmc from this thread.
> (I'll post the change later)
> v1 -> v2: remove an unused variable in __ufshcd_send_uic_cmd
>
> Kiwoong Kim (2):
>   ufs: make __ufshcd_send_uic_cmd not wrapped by host_lock
>   ufs: poll HCS.UCRDY before issuing a UIC command

Applied to 6.6/scsi-staging, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering
RE: [RESEND PATCH v3 0/2] change UIC command handling
Posted by Kiwoong Kim 1 year, 12 months ago
> > v2 -> v3: rule out the change of polling w/ pmc from this thread.
> > (I'll post the change later)
> > v1 -> v2: remove an unused variable in __ufshcd_send_uic_cmd
> >
> > Kiwoong Kim (2):
> >   ufs: make __ufshcd_send_uic_cmd not wrapped by host_lock
> >   ufs: poll HCS.UCRDY before issuing a UIC command
> 
> Applied to 6.6/scsi-staging, thanks!
> 
> --
> Martin K. Petersen	Oracle Linux Engineering

Hi, Martin

The following patch seems to make trouble because of using
read_poll_timeout.
Its initial version used udelay and after discussion it's been changed.
Could you revert this patch set?

> ufs: poll HCS.UCRDY before issuing a UIC command

[ 4671.226480] [3: kworker/u20:29:17140] BUG: scheduling while atomic:
kworker/u20:29/17140/0x00000002
..
[ 4671.228723] [3: kworker/u20:29:17140]  panic+0x16c/0x388
[ 4671.228745] [3: kworker/u20:29:17140]  check_panic_on_warn+0x60/0x94
[ 4671.228764] [3: kworker/u20:29:17140]  __schedule_bug+0x6c/0x94
[ 4671.228786] [3: kworker/u20:29:17140]  __schedule+0x6f4/0xa64
[ 4671.228806] [3: kworker/u20:29:17140]  schedule+0x7c/0xe8
[ 4671.228824] [3: kworker/u20:29:17140]
schedule_hrtimeout_range_clock+0x98/0x114
[ 4671.228841] [3: kworker/u20:29:17140]  schedule_hrtimeout_range+0x14/0x24
[ 4671.228856] [3: kworker/u20:29:17140]  usleep_range_state+0x60/0x94
[ 4671.228871] [3: kworker/u20:29:17140]  __ufshcd_send_uic_cmd+0xa0/0x1c4
[ 4671.228893] [3: kworker/u20:29:17140]  ufshcd_uic_pwr_ctrl+0x15c/0x390
[ 4671.228908] [3: kworker/u20:29:17140]
ufshcd_uic_hibern8_enter+0x9c/0x25c
[ 4671.228922] [3: kworker/u20:29:17140]
ufshcd_link_state_transition+0x34/0xb0
[ 4671.228939] [3: kworker/u20:29:17140]  __ufshcd_wl_suspend+0x3f0/0x4b4

Thanks you.
Re: [RESEND PATCH v3 0/2] change UIC command handling
Posted by Adrian Hunter 1 year, 12 months ago
On 11/09/23 04:35, Kiwoong Kim wrote:
>>> v2 -> v3: rule out the change of polling w/ pmc from this thread.
>>> (I'll post the change later)
>>> v1 -> v2: remove an unused variable in __ufshcd_send_uic_cmd
>>>
>>> Kiwoong Kim (2):
>>>   ufs: make __ufshcd_send_uic_cmd not wrapped by host_lock
>>>   ufs: poll HCS.UCRDY before issuing a UIC command
>>
>> Applied to 6.6/scsi-staging, thanks!
>>
>> --
>> Martin K. Petersen	Oracle Linux Engineering
> 
> Hi, Martin
> 
> The following patch seems to make trouble because of using
> read_poll_timeout.
> Its initial version used udelay and after discussion it's been changed.
> Could you revert this patch set?
> 
>> ufs: poll HCS.UCRDY before issuing a UIC command
> 
> [ 4671.226480] [3: kworker/u20:29:17140] BUG: scheduling while atomic:
> kworker/u20:29/17140/0x00000002
> ..
> [ 4671.228723] [3: kworker/u20:29:17140]  panic+0x16c/0x388
> [ 4671.228745] [3: kworker/u20:29:17140]  check_panic_on_warn+0x60/0x94
> [ 4671.228764] [3: kworker/u20:29:17140]  __schedule_bug+0x6c/0x94
> [ 4671.228786] [3: kworker/u20:29:17140]  __schedule+0x6f4/0xa64
> [ 4671.228806] [3: kworker/u20:29:17140]  schedule+0x7c/0xe8
> [ 4671.228824] [3: kworker/u20:29:17140]
> schedule_hrtimeout_range_clock+0x98/0x114
> [ 4671.228841] [3: kworker/u20:29:17140]  schedule_hrtimeout_range+0x14/0x24
> [ 4671.228856] [3: kworker/u20:29:17140]  usleep_range_state+0x60/0x94
> [ 4671.228871] [3: kworker/u20:29:17140]  __ufshcd_send_uic_cmd+0xa0/0x1c4
> [ 4671.228893] [3: kworker/u20:29:17140]  ufshcd_uic_pwr_ctrl+0x15c/0x390
> [ 4671.228908] [3: kworker/u20:29:17140]
> ufshcd_uic_hibern8_enter+0x9c/0x25c
> [ 4671.228922] [3: kworker/u20:29:17140]
> ufshcd_link_state_transition+0x34/0xb0
> [ 4671.228939] [3: kworker/u20:29:17140]  __ufshcd_wl_suspend+0x3f0/0x4b4

Do you know what is in that path that makes it an atomic context?
RE: [RESEND PATCH v3 0/2] change UIC command handling
Posted by Kiwoong Kim 1 year, 12 months ago
> >> ufs: poll HCS.UCRDY before issuing a UIC command
> >
> > [ 4671.226480] [3: kworker/u20:29:17140] BUG: scheduling while atomic:
> > kworker/u20:29/17140/0x00000002
> > ..
> > [ 4671.228723] [3: kworker/u20:29:17140]  panic+0x16c/0x388 [
> > 4671.228745] [3: kworker/u20:29:17140]  check_panic_on_warn+0x60/0x94
> > [ 4671.228764] [3: kworker/u20:29:17140]  __schedule_bug+0x6c/0x94 [
> > 4671.228786] [3: kworker/u20:29:17140]  __schedule+0x6f4/0xa64 [
> > 4671.228806] [3: kworker/u20:29:17140]  schedule+0x7c/0xe8 [
> > 4671.228824] [3: kworker/u20:29:17140]
> > schedule_hrtimeout_range_clock+0x98/0x114
> > [ 4671.228841] [3: kworker/u20:29:17140]
> > schedule_hrtimeout_range+0x14/0x24
> > [ 4671.228856] [3: kworker/u20:29:17140]  usleep_range_state+0x60/0x94
> > [ 4671.228871] [3: kworker/u20:29:17140]
> > __ufshcd_send_uic_cmd+0xa0/0x1c4 [ 4671.228893] [3:
> > kworker/u20:29:17140]  ufshcd_uic_pwr_ctrl+0x15c/0x390 [ 4671.228908]
> > [3: kworker/u20:29:17140] ufshcd_uic_hibern8_enter+0x9c/0x25c
> > [ 4671.228922] [3: kworker/u20:29:17140]
> > ufshcd_link_state_transition+0x34/0xb0
> > [ 4671.228939] [3: kworker/u20:29:17140]
> > __ufshcd_wl_suspend+0x3f0/0x4b4
> 
> Do you know what is in that path that makes it an atomic context?

Hi,
This made that.

static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
..
        bool reenable_intr = false;

        mutex_lock(&hba->uic_cmd_mutex); <<<<


At first, I was willing to post together w/ the following patch but I've got a suggestion to split the patch set because of different topic and I split the patch set.
- This patch removes the mutex, so it can fix the issue.
https://lore.kernel.org/linux-scsi/1694051306-172962-1-git-send-email-kwmad.kim@samsung.com/


But now I'm thinking again that simply removing the mutex could hurt atomicity of UIC command process
that the original code intended for the first time.
So I think this polling UCRDY should be modified rather than applying removal of the mutex.
Re: [RESEND PATCH v3 0/2] change UIC command handling
Posted by Adrian Hunter 1 year, 12 months ago
On 11/09/23 09:32, Kiwoong Kim wrote:
>>>> ufs: poll HCS.UCRDY before issuing a UIC command
>>>
>>> [ 4671.226480] [3: kworker/u20:29:17140] BUG: scheduling while atomic:
>>> kworker/u20:29/17140/0x00000002
>>> ..
>>> [ 4671.228723] [3: kworker/u20:29:17140]  panic+0x16c/0x388 [
>>> 4671.228745] [3: kworker/u20:29:17140]  check_panic_on_warn+0x60/0x94
>>> [ 4671.228764] [3: kworker/u20:29:17140]  __schedule_bug+0x6c/0x94 [
>>> 4671.228786] [3: kworker/u20:29:17140]  __schedule+0x6f4/0xa64 [
>>> 4671.228806] [3: kworker/u20:29:17140]  schedule+0x7c/0xe8 [
>>> 4671.228824] [3: kworker/u20:29:17140]
>>> schedule_hrtimeout_range_clock+0x98/0x114
>>> [ 4671.228841] [3: kworker/u20:29:17140]
>>> schedule_hrtimeout_range+0x14/0x24
>>> [ 4671.228856] [3: kworker/u20:29:17140]  usleep_range_state+0x60/0x94
>>> [ 4671.228871] [3: kworker/u20:29:17140]
>>> __ufshcd_send_uic_cmd+0xa0/0x1c4 [ 4671.228893] [3:
>>> kworker/u20:29:17140]  ufshcd_uic_pwr_ctrl+0x15c/0x390 [ 4671.228908]
>>> [3: kworker/u20:29:17140] ufshcd_uic_hibern8_enter+0x9c/0x25c
>>> [ 4671.228922] [3: kworker/u20:29:17140]
>>> ufshcd_link_state_transition+0x34/0xb0
>>> [ 4671.228939] [3: kworker/u20:29:17140]
>>> __ufshcd_wl_suspend+0x3f0/0x4b4
>>
>> Do you know what is in that path that makes it an atomic context?
> 
> Hi,
> This made that.
> 
> static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
> ..
>         bool reenable_intr = false;
> 
>         mutex_lock(&hba->uic_cmd_mutex); <<<<

It is OK to schedule while holding a mutex.  Are you sure
this is the problem?

> 
> 
> At first, I was willing to post together w/ the following patch but I've got a suggestion to split the patch set because of different topic and I split the patch set.
> - This patch removes the mutex, so it can fix the issue.
> https://lore.kernel.org/linux-scsi/1694051306-172962-1-git-send-email-kwmad.kim@samsung.com/
> 
> 
> But now I'm thinking again that simply removing the mutex could hurt atomicity of UIC command process
> that the original code intended for the first time.
> So I think this polling UCRDY should be modified rather than applying removal of the mutex.
> 
> 
>
RE: [RESEND PATCH v3 0/2] change UIC command handling
Posted by Kiwoong Kim 1 year, 12 months ago
> > static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command
> > *cmd) ..
> >         bool reenable_intr = false;
> >
> >         mutex_lock(&hba->uic_cmd_mutex); <<<<
> 
> It is OK to schedule while holding a mutex.  Are you sure this is the
> problem?

Ah, I mis-understood it. It was for not applying this.
https://lore.kernel.org/linux-scsi/782ba5f26f0a96e58d85dff50751787d2d2a6b2b.1693790060.git.kwmad.kim@samsung.com/

So this patch set has no problem. Sorry for bothering all of you.

Thanks.