Patchwork [-v2,2/3] PCI,pciehp: avoid add a device already exist before suspend during resume

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Submitter Yijing Wang
Date July 11, 2013, 9:43 a.m.
Message ID <1373535825-49972-3-git-send-email-wangyijing@huawei.com>
Download mbox | patch
Permalink /patch/258391/
State Superseded
Headers show

Comments

Yijing Wang - July 11, 2013, 9:43 a.m.
Currently, pciehp_resume() try to hot add device if the slot adapter
status return true. But if there are already some devices exist,
namely list_empty(bus->devices) return false. We should not add the device
again, because the device add action will fail. Also print some uncomfortable
messages like this:
	pciehp 0000:00:1c.1:pcie04: Device 0000:03:00.0 already exists at 0000:03:00, cannot hot-add
	pciehp 0000:00:1c.1:pcie04: Cannot add device at 0000:03:00

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Oliver Neukum <oneukum@suse.de>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: linux-pci@vger.kernel.org
---
 drivers/pci/hotplug/pciehp_core.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)
Paul Bolle - July 11, 2013, 2:27 p.m.
On Thu, 2013-07-11 at 17:43 +0800, Yijing Wang wrote:
> Currently, pciehp_resume() try to hot add device if the slot adapter
> status return true. But if there are already some devices exist,
> namely list_empty(bus->devices) return false. We should not add the device
> again, because the device add action will fail. Also print some uncomfortable
> messages like this:
> 	pciehp 0000:00:1c.1:pcie04: Device 0000:03:00.0 already exists at 0000:03:00, cannot hot-add
> 	pciehp 0000:00:1c.1:pcie04: Cannot add device at 0000:03:00
> 
> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> Cc: Paul Bolle <pebolle@tiscali.nl>
> Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
> Cc: Oliver Neukum <oneukum@suse.de>
> Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
> Cc: linux-pci@vger.kernel.org
> ---
>  drivers/pci/hotplug/pciehp_core.c |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
> index 7d72c5e..1542735 100644
> --- a/drivers/pci/hotplug/pciehp_core.c
> +++ b/drivers/pci/hotplug/pciehp_core.c
[...]
> @@ -311,10 +312,12 @@ static int pciehp_resume (struct pcie_device *dev)
>  
>  	/* Check if slot is occupied */
>  	pciehp_get_adapter_status(slot, &status);
> -	if (status)
> -		pciehp_enable_slot(slot);
> -	else
> +	if (status) {
> +		if (list_empty(&pbus->devices))
> +			pciehp_enable_slot(slot);
> +	} else if (!list_empty(&pbus->devices))
>  		pciehp_disable_slot(slot);
> +

Coding style: braces for the "else if" branch too? Or change the first
test to "if (status && list_empty([...]))" and drop the braces?

>  	return 0;
>  }
>  #endif /* PM */


Paul Bolle

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Yijing Wang - July 12, 2013, 2:19 a.m.
>> ---
>>  drivers/pci/hotplug/pciehp_core.c |    9 ++++++---
>>  1 files changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
>> index 7d72c5e..1542735 100644
>> --- a/drivers/pci/hotplug/pciehp_core.c
>> +++ b/drivers/pci/hotplug/pciehp_core.c
> [...]
>> @@ -311,10 +312,12 @@ static int pciehp_resume (struct pcie_device *dev)
>>  
>>  	/* Check if slot is occupied */
>>  	pciehp_get_adapter_status(slot, &status);
>> -	if (status)
>> -		pciehp_enable_slot(slot);
>> -	else
>> +	if (status) {
>> +		if (list_empty(&pbus->devices))
>> +			pciehp_enable_slot(slot);
>> +	} else if (!list_empty(&pbus->devices))
>>  		pciehp_disable_slot(slot);
>> +
> 
> Coding style: braces for the "else if" branch too? Or change the first
> test to "if (status && list_empty([...]))" and drop the braces?

Hmmm, I will add the braces for "else if "

Change the first test "if (status && list_empty([...]))" is not a good idea,
because this change will modify the code logic, for example
if a device was present before suspend and still there during resume, we should do nothing,
but after the logic change, we may disable it.

> 
>>  	return 0;
>>  }
>>  #endif /* PM */
> 
> 
> Paul Bolle
> 
> 
> .
>

Patch

diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 7d72c5e..1542735 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -300,6 +300,7 @@  static int pciehp_resume (struct pcie_device *dev)
 {
 	struct controller *ctrl;
 	struct slot *slot;
+	struct pci_bus *pbus = dev->port->subordinate;
 	u8 status;
 
 	ctrl = get_service_data(dev);
@@ -311,10 +312,12 @@  static int pciehp_resume (struct pcie_device *dev)
 
 	/* Check if slot is occupied */
 	pciehp_get_adapter_status(slot, &status);
-	if (status)
-		pciehp_enable_slot(slot);
-	else
+	if (status) {
+		if (list_empty(&pbus->devices))
+			pciehp_enable_slot(slot);
+	} else if (!list_empty(&pbus->devices))
 		pciehp_disable_slot(slot);
+
 	return 0;
 }
 #endif /* PM */