[PATCH] drm/gem-cma-helper: Change the level of the allocation failure message

[Eric Engestrom]

On Wednesday, 2017-10-04 22:28:54 +0000, Eric Anholt wrote:
> Boris Brezillon <boris.brezillon at free-electrons.com> writes:
> 
> > drm_gem_cma_create() prints an error message when dma_alloc_wc() fails to
> > allocate the amount of memory we requested. This can lead to annoying
> > error messages when CMA is only one possible source of memory for the BO
> > allocation.
> >
> > Turn this error message into a debug one and add a __must_check specifier
> > to make sure all callers are checking the return value.
> >
> > Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
> 
> The __must_check seems unnecessary to me -- you're definitely going to
> be doing something with the return value, because otherwise why did you
> call the object allocate function?

Indeed, `__must_check` (aka `warn_unused_result`) only makes sure the
return value is not discarded, which will probably always be true here.

> The `warn_unused_result` attribute causes a warning to be emitted if
> a caller of the function with this attribute does not use its return
> value.

I think we need a sparse attribute to check that the return value is
IS_ERR()-checked?
(not volunteering, I have no idea how to add a sparse attribute :)