[Intel-gfx] [PATCH v2 01/14] video: fb_defio: preserve user fb_ops

[Noralf Trønnes]

Den 29.11.2019 11.29, skrev Jani Nikula:
> Modifying fb_ops directly to override fb_mmap with fb_deferred_io_mmap
> and then resetting it to NULL afterwards causes problems all over the
> place. First, it prevents making the fbops member of struct fb_info a
> const pointer, which means we can't make struct fb_ops const
> anywhere. Second, a few places have to go out of their way to restore
> the original fb_mmap pointer that gets reset to NULL.
> 
> Since the only user of the fbops->fb_mmap hook is fb_mmap() in fbmem.c,
> call fb_deferred_io_mmap() directly when deferred IO is enabled, and
> avoid modifying fb_ops altogether.
> 
> Simply use info->fbdefio to determine whether deferred IO should be used
> or not. This should be accurate enough for all use cases, although
> perhaps not pedantically correct.
> 
> v2: Simplify considerably by calling fb_deferred_io_mmap() directly
>     (Daniel, Ville)
> 
> Cc: Jaya Kumar <jayalk at intworks.biz>
> Cc: linux-fbdev at vger.kernel.org
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> ---

Nice simple solution:

Acked-by: Noralf Trønnes <noralf at tronnes.org>