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>

3 files changed, 8 insertions, 16 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 3fe816f6beca..283a216ee758 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -500,18 +500,14 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
         struct amdgpu_fpriv *fpriv = p->filp->driver_priv;
         struct amdgpu_bo_list_entry *e;
         struct list_head duplicates;
-        bool need_mmap_lock = false;
         unsigned i, tries = 10;
         int r;
 
         INIT_LIST_HEAD(&p->validated);
 
         p->bo_list = amdgpu_bo_list_get(fpriv, cs->in.bo_list_handle);
-        if (p->bo_list) {
-                need_mmap_lock = p->bo_list->first_userptr !=
-                        p->bo_list->num_entries;
+        if (p->bo_list)
                 amdgpu_bo_list_get_list(p->bo_list, &p->validated);
-        }
 
         INIT_LIST_HEAD(&duplicates);
         amdgpu_vm_get_pd_bo(&fpriv->vm, &p->validated, &p->vm_pd);
@@ -519,9 +515,6 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
         if (p->uf_entry.robj)
                 list_add(&p->uf_entry.tv.head, &p->validated);
 
-        if (need_mmap_lock)
-                down_read(&current->mm->mmap_sem);
-
         while (1) {
                 struct list_head need_pages;
                 unsigned i;
@@ -674,9 +667,6 @@ error_validate:
 
 error_free_pages:
 
-        if (need_mmap_lock)
-                up_read(&current->mm->mmap_sem);
-
         if (p->bo_list) {
                 for (i = p->bo_list->first_userptr;
                      i < p->bo_list->num_entries; ++i) {
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index f1e61b3df640..b0d45c8e6bb3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -318,8 +318,6 @@ int amdgpu_gem_userptr_ioctl(struct drm_device *dev, void *data,
         }
 
         if (args->flags & AMDGPU_GEM_USERPTR_VALIDATE) {
-                down_read(&current->mm->mmap_sem);
-
                 r = amdgpu_ttm_tt_get_user_pages(bo->tbo.ttm,
                                                  bo->tbo.ttm->pages);
                 if (r)
@@ -334,8 +332,6 @@ int amdgpu_gem_userptr_ioctl(struct drm_device *dev, void *data,
                 amdgpu_bo_unreserve(bo);
                 if (r)
                         goto free_pages;
-
-                up_read(&current->mm->mmap_sem);
         }
 
         r = drm_gem_handle_create(filp, gobj, &handle);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 28e121984332..ea0378c8b049 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;
 }