linux-kernel - [PATCH] brd: replace simple_strtol with kstrtoul in ramdisk

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Message-ID: <20251220235924.126384-1-thorsten.blum@linux.dev>
Date: Sun, 21 Dec 2025 00:59:23 +0100
From: Thorsten Blum <thorsten.blum@...ux.dev>
To: Jens Axboe <axboe@...nel.dk>
Cc: Thorsten Blum <thorsten.blum@...ux.dev>,
	linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] brd: replace simple_strtol with kstrtoul in ramdisk_size

Replace simple_strtol() with the recommended kstrtoul() for parsing the
'ramdisk_size=' boot parameter. Unlike simple_strtol(), which returns a
long, kstrtoul() converts the string directly to an unsigned long and
avoids implicit casting.

Check the return value of kstrtoul() and reject invalid values. This
adds error handling while preserving behavior for existing values, and
removes use of the deprecated simple_strtol() helper. The current code
silently sets 'rd_size = 0' if parsing fails, instead of leaving the
default value (CONFIG_BLK_DEV_RAM_SIZE) unchanged.

Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
---
 drivers/block/brd.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 9778259b30d4..a5104cf96609 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -247,8 +247,7 @@ MODULE_ALIAS("rd");
 /* Legacy boot options - nonmodular */
 static int __init ramdisk_size(char *str)
 {
-	rd_size = simple_strtol(str, NULL, 0);
-	return 1;
+	return kstrtoul(str, 0, &rd_size) == 0;
 }
 __setup("ramdisk_size=", ramdisk_size);
 #endif
-- 
Thorsten Blum <thorsten.blum@...ux.dev>
GPG: 1D60 735E 8AEF 3BE4 73B6  9D84 7336 78FD 8DFE EAD4