[Intel-gfx] [PATCH 10/15] drm/i915: Use kmap_atomic for shmem pread

[Chris Wilson]

We only hold the mapped pages for the duration of the memcpy, and never
sleep with them, so we can safely use the cheaper atomic variants of
kmap.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c |   16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7f9be7a..96d4e64 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -314,13 +314,13 @@ slow_shmem_copy(struct page *dst_page,
 {
 	char *dst_vaddr, *src_vaddr;
 
-	dst_vaddr = kmap(dst_page);
-	src_vaddr = kmap(src_page);
+	dst_vaddr = kmap_atomic(dst_page);
+	src_vaddr = kmap_atomic(src_page);
 
 	memcpy(dst_vaddr + dst_offset, src_vaddr + src_offset, length);
 
-	kunmap(src_page);
-	kunmap(dst_page);
+	kunmap_atomic(src_vaddr);
+	kunmap_atomic(dst_vaddr);
 }
 
 static inline void
@@ -343,8 +343,8 @@ slow_shmem_bit17_copy(struct page *gpu_page,
 					       cpu_page, cpu_offset, length);
 	}
 
-	gpu_vaddr = kmap(gpu_page);
-	cpu_vaddr = kmap(cpu_page);
+	gpu_vaddr = kmap_atomic(gpu_page);
+	cpu_vaddr = kmap_atomic(cpu_page);
 
 	/* Copy the data, XORing A6 with A17 (1). The user already knows he's
 	 * XORing with the other bits (A9 for Y, A9 and A10 for X)
@@ -368,8 +368,8 @@ slow_shmem_bit17_copy(struct page *gpu_page,
 		length -= this_length;
 	}
 
-	kunmap(cpu_page);
-	kunmap(gpu_page);
+	kunmap_atomic(cpu_vaddr);
+	kunmap_atomic(gpu_vaddr);
 }
 
 /**
-- 
1.7.4.1