zram: fix error return code

Author: Julia Lawall <Julia.Lawall@lip6.fr>

Return a negative error code on failure.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// 
@@
identifier ret; expression e1,e2;
@@
(
if (\(ret < 0\|ret != 0\))
 { ... return ret; }
|
ret = 0
)
... when != ret = e1
    when != &ret
*if(...)
{
  ... when != ret = e2
      when forall
 return ret;
}
// 

Signed-off-by: Julia Lawall 
Cc: Minchan Kim 
Cc: Nitin Gupta 
Acked-by: Sergey Senozhatsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 

---
 drivers/block/zram/zram_drv.c | 1 +
 1 file changed, 1 insertion(+)
 
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 4491787..c94386a 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1154,6 +1154,7 @@ static int create_device(struct zram *zram, int device_id)
 	if (!zram->disk) {
 		pr_warn("Error allocating disk structure for device %d\n",
 			device_id);
+		ret = -ENOMEM;
 		goto out_free_queue;
 	}