commit b72cf4fca2bb786e20864b5e8755105aa9626fb4
author Christian König <christian.koenig@amd.com> Sun Sep 03 15:22:06 2017 +0200
committer Alex Deucher <alexander.deucher@amd.com> Tue Sep 12 14:24:00 2017 -0400
tree 0f3f739d3fdbe0b8c2a7510689f8fdf482da295d
parent 862095237c392887819e98018d6dc187d8c78726

drm/amdgpu: move taking mmap_sem into get_user_pages v2

This didn't helped as intended, just simplify the code.

v2: unlock mmap_sem in the error path as well

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 28e1219..ea0378c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -622,6 +622,8 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
 	if (!(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY))
 		flags |= FOLL_WRITE;
 
+	down_read(&current->mm->mmap_sem);
+
 	if (gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) {
 		/* check that we only use anonymous memory
 		   to prevent problems with writeback */
@@ -629,8 +631,10 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
 		struct vm_area_struct *vma;
 
 		vma = find_vma(gtt->usermm, gtt->userptr);
-		if (!vma || vma->vm_file || vma->vm_end < end)
+		if (!vma || vma->vm_file || vma->vm_end < end) {
+			up_read(&current->mm->mmap_sem);
 			return -EPERM;
+		}
 	}
 
 	do {
@@ -657,10 +661,12 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
 
 	} while (pinned < ttm->num_pages);
 
+	up_read(&current->mm->mmap_sem);
 	return 0;
 
 release_pages:
 	release_pages(pages, pinned, 0);
+	up_read(&current->mm->mmap_sem);
 	return r;
 }