Re: [PATCH] fbcon: introduce for_each_registered_fb() helper

On Mon, 2018-07-02 at 09:30 +0200, Daniel Vetter wrote:

On Fri, Jun 29, 2018 at 07:20:13PM +0300, Andy Shevchenko wrote:

...

On Fri, 2018-06-29 at 00:20 +0800, Yisheng Xie wrote:

...

LGTM except macro implementation. That's why I have mentioned for_each_pci_bridge() to look at.

...

+#define for_each_registered_fb(i) \

• for (i = 0; i < FB_MAX; i++) \

• if (registered_fb[i])
  

This needs to be protected against nested conditionals. Otherwise compiler issues a warning and even may generate wrong code.

See for_each_if() in include/drm/drmP.h ... we should probably lift that into a general header. The for_each_if() is used all over drm in iterator macros, exactly to avoid surprises.

Wow, didn't know we have a such. It's a good idea to forelift it for wider use.

Yisheng, it seems you may use it in your patch directly.