lib/scatterlist: fix memory leak with scsi-mq

Fix a memory leak with scsi-mq triggered by commands with large data transfer length.

---

For inclusion in 3.18 and 3.17.x.

@@ -203,10 +203,10 @@ void __sg_free_table(struct sg_table *ta
 		}
 
 		table->orig_nents -= sg_size;
-		if (!skip_first_chunk) {
-			free_fn(sgl, alloc_size);
+		if (skip_first_chunk)
 			skip_first_chunk = false;
-		}
+		else
+			free_fn(sgl, alloc_size);
 		sgl = next;
 	}
 

Thanks, this was indeed caused by a last minute change due to someone complaining about my earlier version being a little too convoluted.

Thanks for tracking this down!

Tony> Fix a memory leak with scsi-mq triggered by commands with large Tony> data transfer length.

Tony> Fixes: c53c6d6a68b1 ("scatterlist: allow chaining to preallocated Tony> chunks")

Martin K. Petersen	Oracle Linux Engineering