md/md-bitmap: add 'sync_size' into struct md_bitmap_stats

[ Upstream commit ec6bb299c7c3dd4ca1724d13d5f5fae3ee54fc65 ]

To avoid dereferencing bitmap directly in md-cluster to prepare
inventing a new bitmap.

BTW, also fix following checkpatch warnings:

WARNING: Deprecated use of 'kmap_atomic', prefer 'kmap_local_page' instead
WARNING: Deprecated use of 'kunmap_atomic', prefer 'kunmap_local' instead

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240826074452.1490072-7-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song@kernel.org>
Stable-dep-of: 8d28d0ddb986 ("md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime")
Signed-off-by: Sasha Levin <sashal@kernel.org>

3 files changed, 27 insertions, 14 deletions

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index f7b02d87a6da..80b0cd7b8899 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2115,10 +2115,15 @@ EXPORT_SYMBOL_GPL(md_bitmap_copy_from_slot);
 int md_bitmap_get_stats(struct bitmap *bitmap, struct md_bitmap_stats *stats)
 {
 	struct bitmap_counts *counts;
+	bitmap_super_t *sb;
 
 	if (!bitmap)
 		return -ENOENT;
 
+	sb = kmap_local_page(bitmap->storage.sb_page);
+	stats->sync_size = le64_to_cpu(sb->sync_size);
+	kunmap_local(sb);
+
 	counts = &bitmap->counts;
 	stats->missing_pages = counts->missing_pages;
 	stats->pages = counts->pages;
@@ -2126,6 +2131,7 @@ int md_bitmap_get_stats(struct bitmap *bitmap, struct md_bitmap_stats *stats)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(md_bitmap_get_stats);
 
 int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
 		  int chunksize, int init)
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index 60b86ee93908..840efd1b8a01 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -236,6 +236,7 @@ struct bitmap {
 
 struct md_bitmap_stats {
 	unsigned long	missing_pages;
+	unsigned long	sync_size;
 	unsigned long	pages;
 	struct file	*file;
 };
diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index ca4d3a8d5dd7..6a89f6b5d64f 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -1190,18 +1190,21 @@ out:
  */
 static int cluster_check_sync_size(struct mddev *mddev)
 {
-	int i, rv;
-	bitmap_super_t *sb;
-	unsigned long my_sync_size, sync_size = 0;
-	int node_num = mddev->bitmap_info.nodes;
 	int current_slot = md_cluster_ops->slot_number(mddev);
+	int node_num = mddev->bitmap_info.nodes;
 	struct bitmap *bitmap = mddev->bitmap;
-	char str[64];
 	struct dlm_lock_resource *bm_lockres;
+	struct md_bitmap_stats stats;
+	unsigned long sync_size = 0;
+	unsigned long my_sync_size;
+	char str[64];
+	int i, rv;
 
-	sb = kmap_atomic(bitmap->storage.sb_page);
-	my_sync_size = le64_to_cpu(sb->sync_size);
-	kunmap_atomic(sb);
+	rv = md_bitmap_get_stats(bitmap, &stats);
+	if (rv)
+		return rv;
+
+	my_sync_size = stats.sync_size;
 
 	for (i = 0; i < node_num; i++) {
 		if (i == current_slot)
@@ -1230,15 +1233,18 @@ static int cluster_check_sync_size(struct mddev *mddev)
 			md_bitmap_update_sb(bitmap);
 		lockres_free(bm_lockres);
 
-		sb = kmap_atomic(bitmap->storage.sb_page);
-		if (sync_size == 0)
-			sync_size = le64_to_cpu(sb->sync_size);
-		else if (sync_size != le64_to_cpu(sb->sync_size)) {
-			kunmap_atomic(sb);
+		rv = md_bitmap_get_stats(bitmap, &stats);
+		if (rv) {
+			md_bitmap_free(bitmap);
+			return rv;
+		}
+
+		if (sync_size == 0) {
+			sync_size = stats.sync_size;
+		} else if (sync_size != stats.sync_size) {
 			md_bitmap_free(bitmap);
 			return -1;
 		}
-		kunmap_atomic(sb);
 		md_bitmap_free(bitmap);
 	}