1 files changed, 20 insertions, 5 deletions

diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index 92f42cea5ae4..5d5b091b957a 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -75,6 +75,9 @@ struct ashmem_range {
 /* LRU list of unpinned pages, protected by ashmem_mutex */
 static LIST_HEAD(ashmem_lru_list);
 
+static atomic_t ashmem_shrink_inflight = ATOMIC_INIT(0);
+static DECLARE_WAIT_QUEUE_HEAD(ashmem_shrink_wait);
+
 /*
  * long lru_count - The count of pages on our LRU list.
  *
@@ -439,7 +442,6 @@ out:
 static unsigned long
 ashmem_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 {
-	struct ashmem_range *range, *next;
 	unsigned long freed = 0;
 
 	/* We might recurse into filesystem code, so bail out if necessary */
@@ -449,21 +451,33 @@ ashmem_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 	if (!mutex_trylock(&ashmem_mutex))
 		return -1;
 
-	list_for_each_entry_safe(range, next, &ashmem_lru_list, lru) {
+	while (!list_empty(&ashmem_lru_list)) {
+		struct ashmem_range *range =
+			list_first_entry(&ashmem_lru_list, typeof(*range), lru);
 		loff_t start = range->pgstart * PAGE_SIZE;
 		loff_t end = (range->pgend + 1) * PAGE_SIZE;
+		struct file *f = range->asma->file;
 
-		range->asma->file->f_op->fallocate(range->asma->file,
-				FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
-				start, end - start);
+		get_file(f);
+		atomic_inc(&ashmem_shrink_inflight);
 		range->purged = ASHMEM_WAS_PURGED;
 		lru_del(range);
 
 		freed += range_size(range);
+		mutex_unlock(&ashmem_mutex);
+		f->f_op->fallocate(f,
+				   FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+				   start, end - start);
+		fput(f);
+		if (atomic_dec_and_test(&ashmem_shrink_inflight))
+			wake_up_all(&ashmem_shrink_wait);
+		if (!mutex_trylock(&ashmem_mutex))
+			goto out;
 		if (--sc->nr_to_scan <= 0)
 			break;
 	}
 	mutex_unlock(&ashmem_mutex);
+out:
 	return freed;
 }
 
@@ -714,6 +728,7 @@ static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd,
 		return -EFAULT;
 
 	mutex_lock(&ashmem_mutex);
+	wait_event(ashmem_shrink_wait, !atomic_read(&ashmem_shrink_inflight));
 
 	if (!asma->file)
 		goto out_unlock;