On Thu, Jul 31, 2014 at 11:31:10AM +0100, Matt Fleming wrote:
> On Wed, 30 Jul, at 12:23:32PM, Josh Triplett wrote:
> > @@ -61,14 +81,18 @@ void __init efi_bgrt_init(void)
> > early_iounmap(image, sizeof(bmp_header));
> > bgrt_image_size = bmp_header.size;
> >
> > - bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL);
> > - if (!bgrt_image)
> > + bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
> > + if (!bgrt_image) {
> > + pr_err("Ignoring BGRT: failed to allocate memory for image (wanted %zu bytes)\n",
> > + bgrt_image_size);
> > return;
>
> I'm not sure that using __GFP_NOWARN is the right thing to do here. If
> for some reason we can't handle the BGRT image we should include checks
> in the BGRT code, rather than relying on the page-allocation machinery
> to save us.
>
> Let's just use an explicit limit on the size of the BGRT image we're
> willing to handle.
I started to add an explicit limit, but any reasonable limit (large
enough for modern screens) would be large enough that there's still a
non-trivial possibility of allocation failure. And I think it makes
sense for BGRT image allocation to be non-fatal and minimally noisy
(just a single-line error, not a scary-looking allocation warning),
considering the highly optional and cosmetic nature of BGRT. So, I
believe __GFP_NOWARN makes sense.
- Josh Triplett
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