[Intel-gfx] [PATCH] drm/i915/selftests: Switch 4k kmalloc to use get_free_page for alignment

[Chris Wilson]

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" <nitin.r.gote at intel.com>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: "Gote, Nitin R" <nitin.r.gote at intel.com>
---
 drivers/gpu/drm/i915/gt/selftest_lrc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index c8753559c44c..a885f2fb6e66 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -4761,7 +4761,7 @@ 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);
 	if (!lrc)
 		return -ENOMEM;
 
@@ -4850,7 +4850,7 @@ static int live_lrc_layout(void *arg)
 			break;
 	}
 
-	kfree(lrc);
+	free_page((unsigned long)lrc);
 	return err;
 }
 
-- 
2.20.1