diff mbox series

[V3,31/37] drm/ttm: Replace kmap_atomic() usage

Message ID 20201103095859.726187546@linutronix.de (mailing list archive)
State Not Applicable
Headers show
Series mm/highmem: Preemptible variant of kmap_atomic & friends | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/merge (09a0972ac14f67d600aa3c80035367a8074e90eb)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/next (3cea11cd5e3b00d91caf0b4730194039b45c5891)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch linus/master (b7cbaf59f62f8ab8f157698f9e31642bff525bd0)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/fixes (99f070b62322a4b8c1252952735806d09eb44b68)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch linux-next (c50585161e791d5ddb924da98741fdf413a0480a)
snowpatch_ozlabs/apply_patch fail Failed to apply to any branch

Commit Message

Thomas Gleixner Nov. 3, 2020, 9:27 a.m. UTC 
There is no reason to disable pagefaults and preemption as a side effect of
kmap_atomic_prot().

Use kmap_local_page_prot() instead and document the reasoning for the
mapping usage with the given pgprot.

Remove the NULL pointer check for the map. These functions return a valid
address for valid pages and the return was bogus anyway as it would have
left preemption and pagefaults disabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
---
V3: New patch
---
 drivers/gpu/drm/ttm/ttm_bo_util.c |   20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)
diff mbox series

Patch

--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -181,13 +181,15 @@  static int ttm_copy_io_ttm_page(struct t
 		return -ENOMEM;
 
 	src = (void *)((unsigned long)src + (page << PAGE_SHIFT));
-	dst = kmap_atomic_prot(d, prot);
-	if (!dst)
-		return -ENOMEM;
+	/*
+	 * Ensure that a highmem page is mapped with the correct
+	 * pgprot. For non highmem the mapping is already there.
+	 */
+	dst = kmap_local_page_prot(d, prot);
 
 	memcpy_fromio(dst, src, PAGE_SIZE);
 
-	kunmap_atomic(dst);
+	kunmap_local(dst);
 
 	return 0;
 }
@@ -203,13 +205,15 @@  static int ttm_copy_ttm_io_page(struct t
 		return -ENOMEM;
 
 	dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT));
-	src = kmap_atomic_prot(s, prot);
-	if (!src)
-		return -ENOMEM;
+	/*
+	 * Ensure that a highmem page is mapped with the correct
+	 * pgprot. For non highmem the mapping is already there.
+	 */
+	src = kmap_local_page_prot(s, prot);
 
 	memcpy_toio(dst, src, PAGE_SIZE);
 
-	kunmap_atomic(src);
+	kunmap_local(src);
 
 	return 0;
 }