linux-kernel - [PATCH v2] initrd: Fix unused variable warning in rd_load

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Message-ID: <20250911094908.1308767-2-thorsten.blum@linux.dev>
Date: Thu, 11 Sep 2025 11:49:08 +0200
From: Thorsten Blum <thorsten.blum@...ux.dev>
To: Alexander Viro <viro@...iv.linux.org.uk>,
	Christian Brauner <brauner@...nel.org>,
	Jan Kara <jack@...e.cz>
Cc: linux-s390@...r.kernel.org,
	Heiko Carstens <hca@...ux.ibm.com>,
	Thorsten Blum <thorsten.blum@...ux.dev>,
	linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] initrd: Fix unused variable warning in rd_load_image() on s390

The local variables 'rotator' and 'rotate' (used for the progress
indicator) aren't used on s390. Building the kernel with W=1 generates
the following warning:

init/do_mounts_rd.c:192:17: warning: variable 'rotate' set but not used [-Wunused-but-set-variable]
 192 |         unsigned short rotate = 0;
     |                        ^
1 warning generated.

Remove the preprocessor directives and use the IS_ENABLED(CONFIG_S390)
macro instead, allowing the compiler to optimize away unused variables
and avoid the warning on s390.

Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
---
Changes in v2:
- Use IS_ENABLED(CONFIG_S390) instead of the preprocessor directives as
  suggested by Heiko Carstens <hca@...ux.ibm.com>
- Link to v1: https://lore.kernel.org/lkml/20250908121303.180886-2-thorsten.blum@linux.dev/
---
 init/do_mounts_rd.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index ac021ae6e6fa..3cbdf43a42df 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -191,9 +191,7 @@ int __init rd_load_image(char *from)
 	char *buf = NULL;
 	unsigned short rotate = 0;
 	decompress_fn decompressor = NULL;
-#if !defined(CONFIG_S390)
 	char rotator[4] = { '|' , '/' , '-' , '\\' };
-#endif
 
 	out_file = filp_open("/dev/ram", O_RDWR, 0);
 	if (IS_ERR(out_file))
@@ -255,12 +253,10 @@ int __init rd_load_image(char *from)
 		}
 		kernel_read(in_file, buf, BLOCK_SIZE, &in_pos);
 		kernel_write(out_file, buf, BLOCK_SIZE, &out_pos);
-#if !defined(CONFIG_S390)
-		if (!(i % 16)) {
+		if (!IS_ENABLED(CONFIG_S390) && !(i % 16)) {
 			pr_cont("%c\b", rotator[rotate & 0x3]);
 			rotate++;
 		}
-#endif
 	}
 	pr_cont("done.\n");
 
-- 
2.51.0