diff mbox series

[1/2] PCI: Use software node API with additional device properties

Message ID 20210929133729.9427-2-heikki.krogerus@linux.intel.com (mailing list archive)
State Superseded
Headers show
Series device property: Remove device_add_properties() | expand

Commit Message

Heikki Krogerus Sept. 29, 2021, 1:37 p.m. UTC
Using device_create_managed_software_node() to inject the
properties in quirk_huawei_pcie_sva() instead of with the
old device_add_properties() API.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/pci/quirks.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Bjorn Helgaas Sept. 29, 2021, 5:08 p.m. UTC | #1
[+cc Zhangfei, author of 8304a3a199ee ("PCI: Set dma-can-stall for
HiSilicon chips"), which added this]

On Wed, Sep 29, 2021 at 04:37:28PM +0300, Heikki Krogerus wrote:
> Using device_create_managed_software_node() to inject the
> properties in quirk_huawei_pcie_sva() instead of with the
> old device_add_properties() API.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

This is fine with me, but please update the subject line and commit
log something like this:

  PCI: Convert to device_create_managed_software_node()

  In quirk_huawei_pcie_sva(), use device_create_managed_software_node()
  instead of device_add_properties() to set the "dma-can-stall"
  property.

  This resolves a software node lifetime issue (see 151f6ff78cdf
  ("software node: Provide replacement for device_add_properties()"))
  and paves the way for removing device_add_properties() completely.

Actually, 8304a3a199ee was merged during the v5.15 merge window, so if
this does in fact fix a lifetime issue, I can merge this before
v5.15-final.

I know *this* quirk applies to AMBA devices, and I assume they cannot
be removed, so there's no actual lifetime problem in this particular
case, but in general it looks like a problem for PCI devices.

> ---
>  drivers/pci/quirks.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index b6b4c803bdc94..fe5eedba47908 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -1850,7 +1850,7 @@ static void quirk_huawei_pcie_sva(struct pci_dev *pdev)
>  	 * can set it directly.
>  	 */
>  	if (!pdev->dev.of_node &&
> -	    device_add_properties(&pdev->dev, properties))
> +	    device_create_managed_software_node(&pdev->dev, properties, NULL))
>  		pci_warn(pdev, "could not add stall property");
>  }
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa250, quirk_huawei_pcie_sva);
> -- 
> 2.33.0
>
Zhangfei Gao Sept. 30, 2021, 2:33 a.m. UTC | #2
On 2021/9/30 上午1:08, Bjorn Helgaas wrote:
> [+cc Zhangfei, author of 8304a3a199ee ("PCI: Set dma-can-stall for
> HiSilicon chips"), which added this]
>
> On Wed, Sep 29, 2021 at 04:37:28PM +0300, Heikki Krogerus wrote:
>> Using device_create_managed_software_node() to inject the
>> properties in quirk_huawei_pcie_sva() instead of with the
>> old device_add_properties() API.
>>
>> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> This is fine with me, but please update the subject line and commit
> log something like this:
>
>    PCI: Convert to device_create_managed_software_node()
>
>    In quirk_huawei_pcie_sva(), use device_create_managed_software_node()
>    instead of device_add_properties() to set the "dma-can-stall"
>    property.
>
>    This resolves a software node lifetime issue (see 151f6ff78cdf
>    ("software node: Provide replacement for device_add_properties()"))
>    and paves the way for removing device_add_properties() completely.
>
> Actually, 8304a3a199ee was merged during the v5.15 merge window, so if
> this does in fact fix a lifetime issue, I can merge this before
> v5.15-final.
>
> I know *this* quirk applies to AMBA devices, and I assume they cannot
> be removed, so there's no actual lifetime problem in this particular
> case, but in general it looks like a problem for PCI devices.
Thanks Bjorn
This patch also works, though the quirk is for platform devices and not 
removed.

Acked-by: Zhangfei Gao <zhangfei.gao@linaro.org>
>
>> ---
>>   drivers/pci/quirks.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
>> index b6b4c803bdc94..fe5eedba47908 100644
>> --- a/drivers/pci/quirks.c
>> +++ b/drivers/pci/quirks.c
>> @@ -1850,7 +1850,7 @@ static void quirk_huawei_pcie_sva(struct pci_dev *pdev)
>>   	 * can set it directly.
>>   	 */
>>   	if (!pdev->dev.of_node &&
>> -	    device_add_properties(&pdev->dev, properties))
>> +	    device_create_managed_software_node(&pdev->dev, properties, NULL))
>>   		pci_warn(pdev, "could not add stall property");
>>   }
>>   DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa250, quirk_huawei_pcie_sva);
>> -- 
>> 2.33.0
>>
Heikki Krogerus Sept. 30, 2021, 10:05 a.m. UTC | #3
Hi guys,

On Thu, Sep 30, 2021 at 10:33:27AM +0800, Zhangfei Gao wrote:
> On 2021/9/30 上午1:08, Bjorn Helgaas wrote:
> > [+cc Zhangfei, author of 8304a3a199ee ("PCI: Set dma-can-stall for
> > HiSilicon chips"), which added this]
> > 
> > On Wed, Sep 29, 2021 at 04:37:28PM +0300, Heikki Krogerus wrote:
> > > Using device_create_managed_software_node() to inject the
> > > properties in quirk_huawei_pcie_sva() instead of with the
> > > old device_add_properties() API.
> > > 
> > > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > This is fine with me, but please update the subject line and commit
> > log something like this:
> > 
> >    PCI: Convert to device_create_managed_software_node()
> > 
> >    In quirk_huawei_pcie_sva(), use device_create_managed_software_node()
> >    instead of device_add_properties() to set the "dma-can-stall"
> >    property.
> > 
> >    This resolves a software node lifetime issue (see 151f6ff78cdf
> >    ("software node: Provide replacement for device_add_properties()"))
> >    and paves the way for removing device_add_properties() completely.
> > 
> > Actually, 8304a3a199ee was merged during the v5.15 merge window, so if
> > this does in fact fix a lifetime issue, I can merge this before
> > v5.15-final.

It does not fix lifetime issues. This is because device_del() called
device_remove_properties() unconditionally with every device.

There should be no functional impact.

> > I know *this* quirk applies to AMBA devices, and I assume they cannot
> > be removed, so there's no actual lifetime problem in this particular
> > case, but in general it looks like a problem for PCI devices.
> Thanks Bjorn
> This patch also works, though the quirk is for platform devices and not
> removed.

If the device is really never removed, then we could also constify the
node and the properties in it. Then the patch would look like this:

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index b6b4c803bdc94..3dc7a1c62bf24 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1833,13 +1833,17 @@ DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_HUAWEI, 0x1610, PCI_CLASS_BRIDGE_PCI
  * even when a "PCI" device turns out to be a regular old SoC device
  * dressed up as a RCiEP and normal rules don't apply.
  */
+static const struct property_entry huawei_pcie_sva_props[] = {
+       PROPERTY_ENTRY_BOOL("dma-can-stall"),
+       { }
+};
+
+static const struct software_node huawei_pcie_sva_swnode = {
+       .properties = huawei_pcie_sva_props,
+};
+
 static void quirk_huawei_pcie_sva(struct pci_dev *pdev)
 {
-       struct property_entry properties[] = {
-               PROPERTY_ENTRY_BOOL("dma-can-stall"),
-               {},
-       };
-
        if (pdev->revision != 0x21 && pdev->revision != 0x30)
                return;
 
@@ -1850,7 +1854,7 @@ static void quirk_huawei_pcie_sva(struct pci_dev *pdev)
         * can set it directly.
         */
        if (!pdev->dev.of_node &&
-           device_add_properties(&pdev->dev, properties))
+           device_add_software_node(&pdev->dev, &huawei_pcie_sva_swnode))
                pci_warn(pdev, "could not add stall property");
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa250, quirk_huawei_pcie_sva);


Let me know if you prefer it that way.

thanks,
Andy Shevchenko Sept. 30, 2021, 10:19 a.m. UTC | #4
On Thu, Sep 30, 2021 at 1:06 PM Heikki Krogerus
<heikki.krogerus@linux.intel.com> wrote:
> On Thu, Sep 30, 2021 at 10:33:27AM +0800, Zhangfei Gao wrote:

...

> If the device is really never removed, then we could also constify the
> node and the properties in it. Then the patch would look like this:

I'm not sure the user can't force removal of the device (via PCI
rescan, for example,, or via unbind/bind cycle). I guess this way
should be really taken carefully.
Rafael J. Wysocki Sept. 30, 2021, 10:37 a.m. UTC | #5
On Thu, Sep 30, 2021 at 12:20 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, Sep 30, 2021 at 1:06 PM Heikki Krogerus
> <heikki.krogerus@linux.intel.com> wrote:
> > On Thu, Sep 30, 2021 at 10:33:27AM +0800, Zhangfei Gao wrote:
>
> ...
>
> > If the device is really never removed, then we could also constify the
> > node and the properties in it. Then the patch would look like this:
>
> I'm not sure the user can't force removal of the device (via PCI
> rescan, for example,, or via unbind/bind cycle).

The sysfs unbind doesn't remove the device, though, AFAICS.  It just
unbinds the driver from it, if any.

> I guess this way should be really taken carefully.

But I agree.
Heikki Krogerus Sept. 30, 2021, 11:26 a.m. UTC | #6
On Thu, Sep 30, 2021 at 12:37:27PM +0200, Rafael J. Wysocki wrote:
> On Thu, Sep 30, 2021 at 12:20 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> >
> > On Thu, Sep 30, 2021 at 1:06 PM Heikki Krogerus
> > <heikki.krogerus@linux.intel.com> wrote:
> > > On Thu, Sep 30, 2021 at 10:33:27AM +0800, Zhangfei Gao wrote:
> >
> > ...
> >
> > > If the device is really never removed, then we could also constify the
> > > node and the properties in it. Then the patch would look like this:
> >
> > I'm not sure the user can't force removal of the device (via PCI
> > rescan, for example,, or via unbind/bind cycle).
> 
> The sysfs unbind doesn't remove the device, though, AFAICS.  It just
> unbinds the driver from it, if any.
> 
> > I guess this way should be really taken carefully.
> 
> But I agree.

OK. Makes sense.

Thanks guys,
diff mbox series

Patch

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index b6b4c803bdc94..fe5eedba47908 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1850,7 +1850,7 @@  static void quirk_huawei_pcie_sva(struct pci_dev *pdev)
 	 * can set it directly.
 	 */
 	if (!pdev->dev.of_node &&
-	    device_add_properties(&pdev->dev, properties))
+	    device_create_managed_software_node(&pdev->dev, properties, NULL))
 		pci_warn(pdev, "could not add stall property");
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0xa250, quirk_huawei_pcie_sva);