[PATCH v2 2/3] loop: replace simple_strtol() with kstrtoint()

[Tao Cui <cui.tao@linux.dev>]

From: Tao Cui <cuitao@kylinos.cn>

simple_strtol() is deprecated and swallows errors.  Use kstrtoint()
in the max_loop setup code; an invalid option keeps the default and
now says so.

Only mark max_loop_specified when the option was parsed successfully.
With simple_strtol() a garbage string yields max_loop = 0, and
loop_probe()'s "max_loop_specified && max_loop" check short-circuits
on 0, so legacy autoloading is not capped.  Keeping max_loop at its
default while still setting max_loop_specified would instead turn the
default into a hard upper bound for dynamic device creation.  This
mirrors what max_loop_param_set_int() already does for the module
parameter.

Signed-off-by: Tao Cui <cuitao@kylinos.cn>

---
Changes in v2:
- move max_loop_specified = true under the success path, pointed out
  by an AI-assisted review of v1.
---
 drivers/block/loop.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 68a9cc7aeb13..126f42580632 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2341,7 +2341,10 @@ module_exit(loop_exit);
 #ifndef MODULE
 static int __init max_loop_setup(char *str)
 {
-	max_loop = simple_strtol(str, NULL, 0);
+	if (kstrtoint(str, 0, &max_loop)) {
+		pr_warn("loop: invalid max_loop, keeping default\n");
+		return 1;
+	}
 #ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
 	max_loop_specified = true;
 #endif
-- 
2.43.0