fs/proc/vmcore: a few cleanups for vmcore_add_device_dump()

There are two cleanups for vmcore_add_device_dump().  Return -ENOMEM
directly rather than goto the label to simplify the code and use
scoped_guard() to simplify the lock/unlock code.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Su Hui <[email protected]>
Reviewed-by: Dan Carpenter <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Dave Young <[email protected]>
Cc: Suhui <[email protected]>
Cc: Vivek Goyal <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: Su Hui

fs/proc/vmcore.c

@@ -1490,10 +1490,8 @@ int vmcore_add_device_dump(struct vmcoredd_data *data)
 		return -EINVAL;
 
 	dump = vzalloc(sizeof(*dump));
-	if (!dump) {
-		ret = -ENOMEM;
-		goto out_err;
-	}
+	if (!dump)
+		return -ENOMEM;
 
 	/* Keep size of the buffer page aligned so that it can be mmaped */
 	data_size = roundup(sizeof(struct vmcoredd_header) + data->size,
@@ -1519,22 +1517,19 @@ int vmcore_add_device_dump(struct vmcoredd_data *data)
 	dump->size = data_size;
 
 	/* Add the dump to driver sysfs list and update the elfcore hdr */
-	mutex_lock(&vmcore_mutex);
-	if (vmcore_opened)
-		pr_warn_once("Unexpected adding of device dump\n");
-	if (vmcore_open) {
-		ret = -EBUSY;
-		goto unlock;
-	}
+	scoped_guard(mutex, &vmcore_mutex) {
+		if (vmcore_opened)
+			pr_warn_once("Unexpected adding of device dump\n");
+		if (vmcore_open) {
+			ret = -EBUSY;
+			goto out_err;
+		}
 
-	list_add_tail(&dump->list, &vmcoredd_list);
-	vmcoredd_update_size(data_size);
-	mutex_unlock(&vmcore_mutex);
+		list_add_tail(&dump->list, &vmcoredd_list);
+		vmcoredd_update_size(data_size);
+	}
 	return 0;
 
-unlock:
-	mutex_unlock(&vmcore_mutex);
-
 out_err:
 	vfree(buf);
 	vfree(dump);