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* [PATCH] drivers/pci/hotplug: Handle presence detection change properly
@ 2016-12-20  6:49 Gavin Shan
  2016-12-20  9:37 ` Greg KH
  2016-12-22  4:26 ` Gavin Shan
  0 siblings, 2 replies; 4+ messages in thread
From: Gavin Shan @ 2016-12-20  6:49 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: Gavin Shan, stable, #v4.9+

The surprise hotplug is driven by interrupt in PowerNV PCI hotplug
driver. In the interrupt handler, pnv_php_interrupt(), we bail when
pnv_pci_get_presence_state() returns zero wrongly. It causes the
presence change event is always ignored incorrectly.

This fixes the issue by bailing on error (non-zero value) returned
from pnv_pci_get_presence_state().

Fixes: 360aebd85a4 ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
Cc: stable@vger.kernel.org #v4.9+
Reported-by: Hank Chang <hankmax0000@gmail.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: Willie Liauw <williel@supermicro.com.tw>
---
 drivers/pci/hotplug/pnv_php.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
index 56efaf7..38a2309 100644
--- a/drivers/pci/hotplug/pnv_php.c
+++ b/drivers/pci/hotplug/pnv_php.c
@@ -707,8 +707,12 @@ static irqreturn_t pnv_php_interrupt(int irq, void *data)
 		added = !!(lsts & PCI_EXP_LNKSTA_DLLLA);
 	} else if (sts & PCI_EXP_SLTSTA_PDC) {
 		ret = pnv_pci_get_presence_state(php_slot->id, &presence);
-		if (!ret)
+		if (ret) {
+			dev_warn(&pdev->dev, "PCI slot [%s] error %d handling PDC event (0x%04x)\n",
+				php_slot->name, ret, sts);
 			return IRQ_HANDLED;
+		}
+
 		added = !!(presence == OPAL_PCI_SLOT_PRESENT);
 	} else {
 		return IRQ_NONE;
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH] drivers/pci/hotplug: Handle presence detection change properly
  2016-12-20  6:49 [PATCH] drivers/pci/hotplug: Handle presence detection change properly Gavin Shan
@ 2016-12-20  9:37 ` Greg KH
  2016-12-20 23:06   ` Gavin Shan
  2016-12-22  4:26 ` Gavin Shan
  1 sibling, 1 reply; 4+ messages in thread
From: Greg KH @ 2016-12-20  9:37 UTC (permalink / raw)
  To: Gavin Shan; +Cc: linuxppc-dev, stable, #v4.9+

On Tue, Dec 20, 2016 at 05:49:33PM +1100, Gavin Shan wrote:
> The surprise hotplug is driven by interrupt in PowerNV PCI hotplug
> driver. In the interrupt handler, pnv_php_interrupt(), we bail when
> pnv_pci_get_presence_state() returns zero wrongly. It causes the
> presence change event is always ignored incorrectly.
> 
> This fixes the issue by bailing on error (non-zero value) returned
> from pnv_pci_get_presence_state().
> 
> Fixes: 360aebd85a4 ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
> Cc: stable@vger.kernel.org #v4.9+
> Reported-by: Hank Chang <hankmax0000@gmail.com>
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
> Tested-by: Willie Liauw <williel@supermicro.com.tw>
> ---
>  drivers/pci/hotplug/pnv_php.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
> index 56efaf7..38a2309 100644
> --- a/drivers/pci/hotplug/pnv_php.c
> +++ b/drivers/pci/hotplug/pnv_php.c
> @@ -707,8 +707,12 @@ static irqreturn_t pnv_php_interrupt(int irq, void *data)
>  		added = !!(lsts & PCI_EXP_LNKSTA_DLLLA);
>  	} else if (sts & PCI_EXP_SLTSTA_PDC) {
>  		ret = pnv_pci_get_presence_state(php_slot->id, &presence);
> -		if (!ret)
> +		if (ret) {
> +			dev_warn(&pdev->dev, "PCI slot [%s] error %d handling PDC event (0x%04x)\n",
> +				php_slot->name, ret, sts);

What can a user do with this warning?


^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] drivers/pci/hotplug: Handle presence detection change properly
  2016-12-20  9:37 ` Greg KH
@ 2016-12-20 23:06   ` Gavin Shan
  0 siblings, 0 replies; 4+ messages in thread
From: Gavin Shan @ 2016-12-20 23:06 UTC (permalink / raw)
  To: Greg KH; +Cc: Gavin Shan, linuxppc-dev, stable, #v4.9+

On Tue, Dec 20, 2016 at 10:37:09AM +0100, Greg KH wrote:
>On Tue, Dec 20, 2016 at 05:49:33PM +1100, Gavin Shan wrote:
>> The surprise hotplug is driven by interrupt in PowerNV PCI hotplug
>> driver. In the interrupt handler, pnv_php_interrupt(), we bail when
>> pnv_pci_get_presence_state() returns zero wrongly. It causes the
>> presence change event is always ignored incorrectly.
>> 
>> This fixes the issue by bailing on error (non-zero value) returned
>> from pnv_pci_get_presence_state().
>> 
>> Fixes: 360aebd85a4 ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
>> Cc: stable@vger.kernel.org #v4.9+
>> Reported-by: Hank Chang <hankmax0000@gmail.com>
>> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>> Tested-by: Willie Liauw <williel@supermicro.com.tw>
>> ---
>>  drivers/pci/hotplug/pnv_php.c | 6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
>> index 56efaf7..38a2309 100644
>> --- a/drivers/pci/hotplug/pnv_php.c
>> +++ b/drivers/pci/hotplug/pnv_php.c
>> @@ -707,8 +707,12 @@ static irqreturn_t pnv_php_interrupt(int irq, void *data)
>>  		added = !!(lsts & PCI_EXP_LNKSTA_DLLLA);
>>  	} else if (sts & PCI_EXP_SLTSTA_PDC) {
>>  		ret = pnv_pci_get_presence_state(php_slot->id, &presence);
>> -		if (!ret)
>> +		if (ret) {
>> +			dev_warn(&pdev->dev, "PCI slot [%s] error %d handling PDC event (0x%04x)\n",
>> +				php_slot->name, ret, sts);
>
>What can a user do with this warning?
>

This warning is to catch developer's attention only. It's very
rare for pnv_pci_get_presence_state() to fail as it simply checks
hardware regiter bit (from Slot Status regsiter in PCIe capability
or PHB's Hotplug Override register) in the skiboot firmware.

User needs to retry the operation (hot-add or hot-remove) when
seeing this warning. Greg, please let me know if below message
is better?

dev_warn(&pdev->dev, "PCI slot [%s] error %d getting presence status on event 0x%04x, to retry the operation.\n",
         php_slot->name, ret, sts);

Thanks,
Gavin


^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] drivers/pci/hotplug: Handle presence detection change properly
  2016-12-20  6:49 [PATCH] drivers/pci/hotplug: Handle presence detection change properly Gavin Shan
  2016-12-20  9:37 ` Greg KH
@ 2016-12-22  4:26 ` Gavin Shan
  1 sibling, 0 replies; 4+ messages in thread
From: Gavin Shan @ 2016-12-22  4:26 UTC (permalink / raw)
  To: Gavin Shan; +Cc: linuxppc-dev, stable, #v4.9+

On Tue, Dec 20, 2016 at 05:49:33PM +1100, Gavin Shan wrote:
>The surprise hotplug is driven by interrupt in PowerNV PCI hotplug
>driver. In the interrupt handler, pnv_php_interrupt(), we bail when
>pnv_pci_get_presence_state() returns zero wrongly. It causes the
>presence change event is always ignored incorrectly.
>
>This fixes the issue by bailing on error (non-zero value) returned
>from pnv_pci_get_presence_state().
>
>Fixes: 360aebd85a4 ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
>Cc: stable@vger.kernel.org #v4.9+
>Reported-by: Hank Chang <hankmax0000@gmail.com>
>Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>Tested-by: Willie Liauw <williel@supermicro.com.tw>
>---

Please ignore this one for now. I will post a revised series to fix
more issues found in recent testing. Also, the warning message will
be modified accordingly.

Thanks,
Gavin

> drivers/pci/hotplug/pnv_php.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
>index 56efaf7..38a2309 100644
>--- a/drivers/pci/hotplug/pnv_php.c
>+++ b/drivers/pci/hotplug/pnv_php.c
>@@ -707,8 +707,12 @@ static irqreturn_t pnv_php_interrupt(int irq, void *data)
> 		added = !!(lsts & PCI_EXP_LNKSTA_DLLLA);
> 	} else if (sts & PCI_EXP_SLTSTA_PDC) {
> 		ret = pnv_pci_get_presence_state(php_slot->id, &presence);
>-		if (!ret)
>+		if (ret) {
>+			dev_warn(&pdev->dev, "PCI slot [%s] error %d handling PDC event (0x%04x)\n",
>+				php_slot->name, ret, sts);
> 			return IRQ_HANDLED;
>+		}
>+
> 		added = !!(presence == OPAL_PCI_SLOT_PRESENT);
> 	} else {
> 		return IRQ_NONE;
>-- 
>2.7.4
>


^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-12-22  5:42 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-12-20  6:49 [PATCH] drivers/pci/hotplug: Handle presence detection change properly Gavin Shan
2016-12-20  9:37 ` Greg KH
2016-12-20 23:06   ` Gavin Shan
2016-12-22  4:26 ` Gavin Shan

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