[PATCH v2] drm/i915/gt: Replace kmap with its safer kmap_local_page counterpart

[Andi Shyti]

kmap_local_page(), unlike kmap(), performs a contextualized
mapping of pages. This means the pages are mapped locally to the
thread that created them, making them invisible outside the
thread and safer to use.

Replace kmap() and kunmap() with kmap_local_page() and
kunmap_local() counterparts for improved safety.

Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
Reviewed-by: Krzysztof Karas <krzysztof.karas at intel.com>
---
Cc: Nitin Gote <nitin.r.gote at intel.com>

v1 -> v2:
 - replaced kmap with the _local version also in the
   intel_ggtt_fencing.c file. (Thanks Nitin)

 drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c | 4 ++--
 drivers/gpu/drm/i915/gt/shmem_utils.c        | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c b/drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
index 0ffba50981e3..00f7cd6debf3 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c
@@ -749,7 +749,7 @@ static void swizzle_page(struct page *page)
 	char *vaddr;
 	int i;
 
-	vaddr = kmap(page);
+	vaddr = kmap_local_page(page);
 
 	for (i = 0; i < PAGE_SIZE; i += 128) {
 		memcpy(temp, &vaddr[i], 64);
@@ -757,7 +757,7 @@ static void swizzle_page(struct page *page)
 		memcpy(&vaddr[i + 64], temp, 64);
 	}
 
-	kunmap(page);
+	kunmap_local(vaddr);
 }
 
 /**
diff --git a/drivers/gpu/drm/i915/gt/shmem_utils.c b/drivers/gpu/drm/i915/gt/shmem_utils.c
index bb696b29ee2c..365c4b8b04f4 100644
--- a/drivers/gpu/drm/i915/gt/shmem_utils.c
+++ b/drivers/gpu/drm/i915/gt/shmem_utils.c
@@ -108,7 +108,7 @@ static int __shmem_rw(struct file *file, loff_t off,
 		if (IS_ERR(page))
 			return PTR_ERR(page);
 
-		vaddr = kmap(page);
+		vaddr = kmap_local_page(page);
 		if (write) {
 			memcpy(vaddr + offset_in_page(off), ptr, this);
 			set_page_dirty(page);
@@ -116,7 +116,7 @@ static int __shmem_rw(struct file *file, loff_t off,
 			memcpy(ptr, vaddr + offset_in_page(off), this);
 		}
 		mark_page_accessed(page);
-		kunmap(page);
+		kunmap_local(vaddr);
 		put_page(page);
 
 		len -= this;
@@ -143,11 +143,11 @@ int shmem_read_to_iosys_map(struct file *file, loff_t off,
 		if (IS_ERR(page))
 			return PTR_ERR(page);
 
-		vaddr = kmap(page);
+		vaddr = kmap_local_page(page);
 		iosys_map_memcpy_to(map, map_off, vaddr + offset_in_page(off),
 				    this);
 		mark_page_accessed(page);
-		kunmap(page);
+		kunmap_local(vaddr);
 		put_page(page);
 
 		len -= this;
-- 
2.47.2