linux-kernel - [PATCH 2/9] mm: swap: factor out the actual swap entry freeing logic to new helper

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Message-Id: <20250313210515.9920-3-shikemeng@huaweicloud.com>
Date: Fri, 14 Mar 2025 05:05:08 +0800
From: Kemeng Shi <shikemeng@...weicloud.com>
To: akpm@...ux-foundation.org
Cc: kasong@...cent.com,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/9] mm: swap: factor out the actual swap entry freeing logic to new helper

Factor out the actual swap entry freeing logic to new helper
__swap_entries_free().
This allow us to futher simplify other swap entry freeing code by
leveraging __swap_entries_free() helper function.

Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
---
 mm/swapfile.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 5a775456e26c..7c886f9dd6f9 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1347,6 +1347,25 @@ static struct swap_info_struct *_swap_info_get(swp_entry_t entry)
 	return NULL;
 }
 
+static inline void __swap_entries_free(struct swap_info_struct *si,
+				       struct swap_cluster_info *ci,
+				       swp_entry_t entry, unsigned int nr_pages)
+{
+	unsigned long offset = swp_offset(entry);
+
+	VM_BUG_ON(cluster_is_empty(ci));
+	VM_BUG_ON(ci->count < nr_pages);
+
+	ci->count -= nr_pages;
+	mem_cgroup_uncharge_swap(entry, nr_pages);
+	swap_range_free(si, offset, nr_pages);
+
+	if (!ci->count)
+		free_cluster(si, ci);
+	else
+		partial_free_cluster(si, ci);
+}
+
 static unsigned char swap_entry_put_locked(struct swap_info_struct *si,
 					   unsigned long offset,
 					   unsigned char usage)
@@ -1525,22 +1544,13 @@ static void swap_entry_range_free(struct swap_info_struct *si,
 
 	/* It should never free entries across different clusters */
 	VM_BUG_ON(ci != offset_to_cluster(si, offset + nr_pages - 1));
-	VM_BUG_ON(cluster_is_empty(ci));
-	VM_BUG_ON(ci->count < nr_pages);
 
-	ci->count -= nr_pages;
 	do {
 		VM_BUG_ON(*map != SWAP_HAS_CACHE);
 		*map = 0;
 	} while (++map < map_end);
 
-	mem_cgroup_uncharge_swap(entry, nr_pages);
-	swap_range_free(si, offset, nr_pages);
-
-	if (!ci->count)
-		free_cluster(si, ci);
-	else
-		partial_free_cluster(si, ci);
+	__swap_entries_free(si, ci, entry, nr_pages);
 }
 
 static void cluster_swap_free_nr(struct swap_info_struct *si,
-- 
2.30.0