mm: KSM: fix data type

ksm_stable_node_chains_prune_millisecs is declared as int, but in
stable__node_chains_prune_millisecs_store(), it can store values up to
UINT_MAX.  Change its type to unsigned int.

Link: https://lkml.kernel.org/r/20210806111351.GA71845@asus
Signed-off-by: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: zhans00

mm/ksm.c

@@ -259,7 +259,7 @@ static unsigned long ksm_stable_node_chains;
 static unsigned long ksm_stable_node_dups;
 
 /* Delay in pruning stale stable_node_dups in the stable_node_chains */
-static int ksm_stable_node_chains_prune_millisecs = 2000;
+static unsigned int ksm_stable_node_chains_prune_millisecs = 2000;
 
 /* Maximum number of page slots sharing a stable node */
 static int ksm_max_page_sharing = 256;
@@ -3105,11 +3105,11 @@ stable_node_chains_prune_millisecs_store(struct kobject *kobj,
 					 struct kobj_attribute *attr,
 					 const char *buf, size_t count)
 {
-	unsigned long msecs;
+	unsigned int msecs;
 	int err;
 
-	err = kstrtoul(buf, 10, &msecs);
-	if (err || msecs > UINT_MAX)
+	err = kstrtouint(buf, 10, &msecs);
+	if (err)
 		return -EINVAL;
 
 	ksm_stable_node_chains_prune_millisecs = msecs;