From 8d03344b9df3dca108f8849c71a4eb5e65cebcf4 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 23 Sep 2020 12:41:56 +0100 Subject: [PATCH] drm/i915/selftests: Switch 4k kmalloc to use get_free_page for alignment In generating the reference LRC, we want a page-aligned address for simplicity in computing the offsets within. This then shares the computation for the HW LRC which is mapped and so page aligned, making the comparison straightforward. It seems that kmalloc(4k) is not always returning from a 4k-aligned slab cache (which would give us a page aligned address) so force alignment by explicitly allocating a page. Reported-by: "Gote, Nitin R" Signed-off-by: Chris Wilson Cc: "Gote, Nitin R" Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20200923114156.17749-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gt/selftest_lrc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c index ba6c2be5c8ff..3485cb7c431d 100644 --- a/drivers/gpu/drm/i915/gt/selftest_lrc.c +++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c @@ -139,9 +139,10 @@ static int live_lrc_layout(void *arg) * match the layout saved by HW. */ - lrc = kmalloc(PAGE_SIZE, GFP_KERNEL); + lrc = (u32 *)__get_free_page(GFP_KERNEL); /* requires page alignment */ if (!lrc) return -ENOMEM; + GEM_BUG_ON(offset_in_page(lrc)); err = 0; for_each_engine(engine, gt, id) { @@ -225,7 +226,7 @@ static int live_lrc_layout(void *arg) break; } - kfree(lrc); + free_page((unsigned long)lrc); return err; } -- 2.11.0