[PATCH] staging: android: ashmem: Don't allow range_alloc() to fail.

[Tetsuo Handa]

ashmem_pin() is calling range_shrink() without checking whether
range_alloc() succeeded. Since memory allocation fault injection might
force range_alloc() to fail while range_alloc() is called for only once
for one ioctl() request, make range_alloc() not to fail.

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
 drivers/staging/android/ashmem.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index d40c1d2..a8070a2 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -171,18 +171,14 @@ static inline void lru_del(struct ashmem_range *range)
  * @end:	   The ending page (inclusive)
  *
  * This function is protected by ashmem_mutex.
- *
- * Return: 0 if successful, or -ENOMEM if there is an error
  */
-static int range_alloc(struct ashmem_area *asma,
-		       struct ashmem_range *prev_range, unsigned int purged,
-		       size_t start, size_t end)
+static void range_alloc(struct ashmem_area *asma,
+			struct ashmem_range *prev_range, unsigned int purged,
+			size_t start, size_t end)
 {
 	struct ashmem_range *range;
 
-	range = kmem_cache_zalloc(ashmem_range_cachep, GFP_KERNEL);
-	if (!range)
-		return -ENOMEM;
+	range = kmem_cache_zalloc(ashmem_range_cachep, GFP_KERNEL | __GFP_NOFAIL);
 
 	range->asma = asma;
 	range->pgstart = start;
@@ -193,8 +189,6 @@ static int range_alloc(struct ashmem_area *asma,
 
 	if (range_on_lru(range))
 		lru_add(range);
-
-	return 0;
 }
 
 /**
@@ -687,7 +681,8 @@ static int ashmem_unpin(struct ashmem_area *asma, size_t pgstart, size_t pgend)
 		}
 	}
 
-	return range_alloc(asma, range, purged, pgstart, pgend);
+	range_alloc(asma, range, purged, pgstart, pgend);
+	return 0;
 }
 
 /*
-- 
1.8.3.1