drm/ttm: handle OOM in ttm_tt_swapout

- Without this change I get a general protection fault.
- Also use PTR_ERR where applicable.

Signed-off-by: Maarten Maathuis <madman2003@gmail.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Acked-by: Thomas Hellstrom <thellstrom@vmware.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 11 insertions, 7 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index e2123af7775a..160c2745f8d8 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -476,7 +476,7 @@ static int ttm_tt_swapin(struct ttm_tt *ttm)
         void *from_virtual;
         void *to_virtual;
         int i;
-        int ret;
+        int ret = -ENOMEM;
 
         if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
                 ret = ttm_tt_set_user(ttm, ttm->tsk, ttm->start,
@@ -495,8 +495,10 @@ static int ttm_tt_swapin(struct ttm_tt *ttm)
 
         for (i = 0; i < ttm->num_pages; ++i) {
                 from_page = read_mapping_page(swap_space, i, NULL);
-                if (IS_ERR(from_page))
+                if (IS_ERR(from_page)) {
+                        ret = PTR_ERR(from_page);
                         goto out_err;
+                }
                 to_page = __ttm_tt_get_page(ttm, i);
                 if (unlikely(to_page == NULL))
                         goto out_err;
@@ -519,7 +521,7 @@ static int ttm_tt_swapin(struct ttm_tt *ttm)
         return 0;
 out_err:
         ttm_tt_free_alloced_pages(ttm);
-        return -ENOMEM;
+        return ret;
 }
 
 int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistant_swap_storage)
@@ -531,6 +533,7 @@ int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistant_swap_storage)
         void *from_virtual;
         void *to_virtual;
         int i;
+        int ret = -ENOMEM;
 
         BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
         BUG_ON(ttm->caching_state != tt_cached);
@@ -553,7 +556,7 @@ int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistant_swap_storage)
                                                 0);
                 if (unlikely(IS_ERR(swap_storage))) {
                         printk(KERN_ERR "Failed allocating swap storage.\n");
-                        return -ENOMEM;
+                        return PTR_ERR(swap_storage);
                 }
         } else
                 swap_storage = persistant_swap_storage;
@@ -565,9 +568,10 @@ int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistant_swap_storage)
                 if (unlikely(from_page == NULL))
                         continue;
                 to_page = read_mapping_page(swap_space, i, NULL);
-                if (unlikely(to_page == NULL))
+                if (unlikely(IS_ERR(to_page))) {
+                        ret = PTR_ERR(to_page);
                         goto out_err;
-
+                }
                 preempt_disable();
                 from_virtual = kmap_atomic(from_page, KM_USER0);
                 to_virtual = kmap_atomic(to_page, KM_USER1);
@@ -591,5 +595,5 @@ out_err:
         if (!persistant_swap_storage)
                 fput(swap_storage);
 
-        return -ENOMEM;
+        return ret;
 }