mm/ksm: cleanup mm_slot_entry() invocation

Patch series "mm_slot: following fixup for usage of mm_slot_entry()", v2.

We got some late review commits during review of "mm_slot: fix the usage of
mm_slot_entry()" in [1].


This patch (of 2):

We got some late review commits during review of commit 08498be
("mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL").  Let's
reduce the indentation level and make the code easier to follow by using
gotos to a new label.

Link: https://lkml.kernel.org/r/20251001091900.20041-1-richard.weiyang@gmail.com
Link: https://lkml.kernel.org/r/20251001091900.20041-2-richard.weiyang@gmail.com
Link: https://lkml.kernel.org/r/20250927004539.19308-1-richard.weiyang@gmail.com [1]
Fixes: 08498be ("mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Kiryl Shutsemau <kas@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Raghavendra K T <raghavendra.kt@amd.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Kiryl Shutsemau <kirill@shutemov.name>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: RichardWeiYang

mm/ksm.c

@@ -2921,7 +2921,7 @@ int __ksm_enter(struct mm_struct *mm)
 
 void __ksm_exit(struct mm_struct *mm)
 {
-	struct ksm_mm_slot *mm_slot;
+	struct ksm_mm_slot *mm_slot = NULL;
 	struct mm_slot *slot;
 	int easy_to_free = 0;
 
@@ -2936,19 +2936,20 @@ void __ksm_exit(struct mm_struct *mm)
 
 	spin_lock(&ksm_mmlist_lock);
 	slot = mm_slot_lookup(mm_slots_hash, mm);
-	if (slot) {
-		mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
-		if (ksm_scan.mm_slot != mm_slot) {
-			if (!mm_slot->rmap_list) {
-				hash_del(&slot->hash);
-				list_del(&slot->mm_node);
-				easy_to_free = 1;
-			} else {
-				list_move(&slot->mm_node,
-					  &ksm_scan.mm_slot->slot.mm_node);
-			}
-		}
+	if (!slot)
+		goto unlock;
+	mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
+	if (ksm_scan.mm_slot == mm_slot)
+		goto unlock;
+	if (!mm_slot->rmap_list) {
+		hash_del(&slot->hash);
+		list_del(&slot->mm_node);
+		easy_to_free = 1;
+	} else {
+		list_move(&slot->mm_node,
+			  &ksm_scan.mm_slot->slot.mm_node);
 	}
+unlock:
 	spin_unlock(&ksm_mmlist_lock);
 
 	if (easy_to_free) {