[GTK][WPE] Use drm render nodes in GbmDevice and make the fd global to the process

• Component: ANGLE
• Status: RESOLVED FIXED

[Alejandro G. Castro]

We just need to use render nodes from the library, we do not need the other apis of the primary device file.

[Alejandro G. Castro]

Created attachment 451937 [details]
Patch

[Zan Dobersek]

Comment on attachment 451937 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=451937&action=review

> Source/WebCore/platform/graphics/gbm/GBMDevice.cpp:61
> +    if (globalFd == -1)
> +        getDeviceFd();

This is now open to cross-thread race conditions.

> Source/WebCore/platform/graphics/gbm/GBMDevice.cpp:75
> -int GBMDevice::getDeviceFd()
> +void GBMDevice::getDeviceFd()

This should be moved out into a standalone static function that internally uses std::call_once() to protect against separate threads racing to open the render node.

[Zan Dobersek]

Comment on attachment 451937 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=451937&action=review

> Source/WebCore/platform/graphics/gbm/GBMDevice.cpp:81
>      if (numDevices <=0)

Poor spacing.

> Source/WebCore/platform/graphics/gbm/GBMDevice.cpp:89
> +        globalFd = open(device->nodes[DRM_NODE_RENDER], O_RDWR);

O_CLOEXEC should also be used.

[Alejandro G. Castro]

(In reply to Zan Dobersek from comment #2)
> Comment on attachment 451937 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=451937&action=review
> 
> > Source/WebCore/platform/graphics/gbm/GBMDevice.cpp:61
> > +    if (globalFd == -1)
> > +        getDeviceFd();
> 
> This is now open to cross-thread race conditions.
> 

Good point, we need to protect the first access.

> > Source/WebCore/platform/graphics/gbm/GBMDevice.cpp:75
> > -int GBMDevice::getDeviceFd()
> > +void GBMDevice::getDeviceFd()
> 
> This should be moved out into a standalone static function that internally
> uses std::call_once() to protect against separate threads racing to open the
> render node.

Thanks for the comments! I'll update the patch.

[Alejandro G. Castro]

Created attachment 452063 [details]
Patch

[Zan Dobersek (Reviews)]

Comment on attachment 452063 [details]
Patch

Great, thanks.

[EWS]

Committed r289885 (247323@main): <https://commits.webkit.org/247323@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 452063 [details].

[Radar WebKit Bug Importer]

<rdar://problem/89016322>