[PATCH v5 05/15] md/md-bitmap: add a new parameter 'flush' to bitmap_ops->enabled

[Yu Kuai]

From: Yu Kuai <yuku...@huawei.com>

The method is only used from raid1/raid10 IO path, to check if write
bio should be pluged, the parameter is always set to true for now,
following patch will use this helper in other context like updating
superblock.

Signed-off-by: Yu Kuai <yuku...@huawei.com>
---
 drivers/md/md-bitmap.c | 19 +++++++++++++------
 drivers/md/md-bitmap.h |  2 +-
 drivers/md/raid1-10.c  |  2 +-
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 0ba1da35aa84..3f52716ea6f5 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -232,20 +232,27 @@ static inline char *bmname(struct bitmap *bitmap)
        return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
 }
 
-static bool __bitmap_enabled(struct bitmap *bitmap)
+static bool __bitmap_enabled(struct bitmap *bitmap, bool flush)
 {
-       return bitmap->storage.filemap &&
-              !test_bit(BITMAP_STALE, &bitmap->flags);
+       if (!flush)
+               return true;
+
+       /*
+        * If caller want to flush bitmap pages to underlying disks, check if
+        * there are cached pages in filemap.
+        */
+       return !test_bit(BITMAP_STALE, &bitmap->flags) &&
+              bitmap->storage.filemap != NULL;
 }
 
-static bool bitmap_enabled(struct mddev *mddev)
+static bool bitmap_enabled(struct mddev *mddev, bool flush)
 {
        struct bitmap *bitmap = mddev->bitmap;
 
        if (!bitmap)
                return false;
 
-       return __bitmap_enabled(bitmap);
+       return __bitmap_enabled(bitmap, flush);
 }
 
 /*
@@ -1244,7 +1251,7 @@ static void __bitmap_unplug(struct bitmap *bitmap)
        int dirty, need_write;
        int writing = 0;
 
-       if (!__bitmap_enabled(bitmap))
+       if (!__bitmap_enabled(bitmap, true))
                return;
 
        /* look at each page to see if there are any set bits that need to be
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index 0ceb9e97d21f..63d91831655f 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -62,7 +62,7 @@ struct md_bitmap_stats {
 };
 
 struct bitmap_operations {
-       bool (*enabled)(struct mddev *mddev);
+       bool (*enabled)(struct mddev *mddev, bool flush);
        int (*create)(struct mddev *mddev);
        int (*resize)(struct mddev *mddev, sector_t blocks, int chunksize);
 
diff --git a/drivers/md/raid1-10.c b/drivers/md/raid1-10.c
index b8b3a9069701..4ad051d49cdc 100644
--- a/drivers/md/raid1-10.c
+++ b/drivers/md/raid1-10.c
@@ -140,7 +140,7 @@ static inline bool raid1_add_bio_to_plug(struct mddev 
*mddev, struct bio *bio,
         * If bitmap is not enabled, it's safe to submit the io directly, and
         * this can get optimal performance.
         */
-       if (!mddev->bitmap_ops->enabled(mddev)) {
+       if (!mddev->bitmap_ops->enabled(mddev, true)) {
                raid1_submit_write(bio);
                return true;
        }
-- 
2.39.2