From: Arnd Bergmann Date: Mon, 20 Mar 2017 09:40:28 +0000 (+0100) Subject: drm/i915: split out check for noncontiguous pfn range X-Git-Tag: v4.12~21^2~16^2~101 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=272bce17cc3ef4629e28c38324d81ca72a862115;p=platform%2Fkernel%2Flinux-exynos.git drm/i915: split out check for noncontiguous pfn range We get a warning with gcc-7 about a pointless comparison when using a linear memmap: drivers/gpu/drm/i915/selftests/scatterlist.c: In function 'alloc_table': drivers/gpu/drm/i915/selftests/scatterlist.c:219:66: error: self-comparison always evaluates to false [-Werror=tautological-compare] Splitting out the comparison into a separate function avoids the warning and makes it slightly more obvious what happens. Fixes: 935a2f776aa5 ("drm/i915: Add some selftests for sg_table manipulation") Signed-off-by: Arnd Bergmann Link: http://patchwork.freedesktop.org/patch/msgid/20170320094335.1266306-2-arnd@arndb.de Reviewed-by: Chris Wilson Signed-off-by: Chris Wilson --- diff --git a/drivers/gpu/drm/i915/selftests/scatterlist.c b/drivers/gpu/drm/i915/selftests/scatterlist.c index eb2cda8..1cc5d29 100644 --- a/drivers/gpu/drm/i915/selftests/scatterlist.c +++ b/drivers/gpu/drm/i915/selftests/scatterlist.c @@ -189,6 +189,13 @@ static unsigned int random(unsigned long n, return 1 + (prandom_u32_state(rnd) % 1024); } +static inline bool page_contiguous(struct page *first, + struct page *last, + unsigned long npages) +{ + return first + npages == last; +} + static int alloc_table(struct pfn_table *pt, unsigned long count, unsigned long max, npages_fn_t npages_fn, @@ -216,7 +223,9 @@ static int alloc_table(struct pfn_table *pt, unsigned long npages = npages_fn(n, count, rnd); /* Nobody expects the Sparse Memmap! */ - if (pfn_to_page(pfn + npages) != pfn_to_page(pfn) + npages) { + if (!page_contiguous(pfn_to_page(pfn), + pfn_to_page(pfn + npages), + npages)) { sg_free_table(&pt->st); return -ENOSPC; }