[Intel-gfx] [PATCH 3/3] drm/i915: run shmem_pread_fast() after page fault

[Xiong Zhang]

fault_in_multipages_writeable() will load fault page into physical
memory, then pread can run fast path, no need to run slow path

Signed-off-by: Xiong Zhang <xiong.y.zhang at intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index f194d7e..982df1e 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -459,6 +459,7 @@ i915_gem_shmem_pread(struct drm_device *dev,
 		page_do_bit17_swizzling = obj_do_bit17_swizzling &&
 			(page_to_phys(page) & (1 << 17)) != 0;
 
+read_again:
 		ret = shmem_pread_fast(page, shmem_page_offset, page_length,
 				       user_data, page_do_bit17_swizzling,
 				       needs_clflush);
@@ -475,6 +476,8 @@ i915_gem_shmem_pread(struct drm_device *dev,
 			 * and just continue. */
 			(void)ret;
 			prefaulted = 1;
+			mutex_lock(&dev->struct_mutex);
+			goto read_again;
 		}
 
 		ret = shmem_pread_slow(page, shmem_page_offset, page_length,
-- 
1.8.3.2