Replace simple_strtoul() with the recommended kstrtouint() for parsing
the 'spin_retry=' boot parameter. Unlike simple_strtoul(), which returns
an unsigned long, kstrtouint() converts the string directly to an
unsigned integer.

Check the return value of kstrtouint() and reject invalid values. This
adds error handling while preserving existing behavior for valid values,
and removes use of the deprecated simple_strtoul() helper.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 arch/s390/lib/spinlock.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index 10db1e56a811..b4ca53356b96 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -34,8 +34,7 @@ early_initcall(spin_retry_init);
  */
 static int __init spin_retry_setup(char *str)
 {
-	spin_retry = simple_strtoul(str, &str, 0);
-	return 1;
+	return kstrtouint(str, 0, &spin_retry) == 0;
 }
 __setup("spin_retry=", spin_retry_setup);
 
-- 
Thorsten Blum <thorsten.blum@linux.dev>
GPG: 1D60 735E 8AEF 3BE4 73B6  9D84 7336 78FD 8DFE EAD4