md: factor out a helper rdev_addable() from remove_and_add_spares()

There are no functional changes, just to make the code simpler and
prepare to delay remove_and_add_spares() to md_start_sync().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230825031622.1530464-7-yukuai1@huaweicloud.com

diff --git a/drivers/md/md.c b/drivers/md/md.c
index fd96729c665589e0b0f752e3358567a63c57417a..324e1f3243b6e4005f616c6c8a0d66c12c97f7c1 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9208,6 +9208,31 @@ static bool rdev_is_spare(struct md_rdev *rdev)
               !test_bit(Faulty, &rdev->flags);
 }
 
+static bool rdev_addable(struct md_rdev *rdev)
+{
+       /* rdev is already used, don't add it again. */
+       if (test_bit(Candidate, &rdev->flags) || rdev->raid_disk >= 0 ||
+           test_bit(Faulty, &rdev->flags))
+               return false;
+
+       /* Allow to add journal disk. */
+       if (test_bit(Journal, &rdev->flags))
+               return true;
+
+       /* Allow to add if array is read-write. */
+       if (md_is_rdwr(rdev->mddev))
+               return true;
+
+       /*
+        * For read-only array, only allow to readd a rdev. And if bitmap is
+        * used, don't allow to readd a rdev that is too old.
+        */
+       if (rdev->saved_raid_disk >= 0 && !test_bit(Bitmap_sync, &rdev->flags))
+               return true;
+
+       return false;
+}
+
 static int remove_and_add_spares(struct mddev *mddev,
                                 struct md_rdev *this)
 {
@@ -9265,20 +9290,10 @@ static int remove_and_add_spares(struct mddev *mddev,
                        continue;
                if (rdev_is_spare(rdev))
                        spares++;
-               if (test_bit(Candidate, &rdev->flags))
-                       continue;
-               if (rdev->raid_disk >= 0)
+               if (!rdev_addable(rdev))
                        continue;
-               if (test_bit(Faulty, &rdev->flags))
-                       continue;
-               if (!test_bit(Journal, &rdev->flags)) {
-                       if (!md_is_rdwr(mddev) &&
-                           !(rdev->saved_raid_disk >= 0 &&
-                             !test_bit(Bitmap_sync, &rdev->flags)))
-                               continue;
-
+               if (!test_bit(Journal, &rdev->flags))
                        rdev->recovery_offset = 0;
-               }
                if (mddev->pers->hot_add_disk(mddev, rdev) == 0) {
                        /* failure here is OK */
                        sysfs_link_rdev(mddev, rdev);