md: stop using for_each_mddev in md_do_sync

Just do a plain list_for_each that only grabs a mddev reference in
the case where the thread sleeps and restarts the list iteration.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3dc3985..f7d5865 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8723,7 +8723,6 @@ void md_do_sync(struct md_thread *thread)
        unsigned long update_time;
        sector_t mark_cnt[SYNC_MARKS];
        int last_mark,m;
-       struct list_head *tmp;
        sector_t last_check;
        int skipped = 0;
        struct md_rdev *rdev;
@@ -8787,7 +8786,8 @@ void md_do_sync(struct md_thread *thread)
        try_again:
                if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
                        goto skip;
-               for_each_mddev(mddev2, tmp) {
+               spin_lock(&all_mddevs_lock);
+               list_for_each_entry(mddev2, &all_mddevs, all_mddevs) {
                        if (mddev2 == mddev)
                                continue;
                        if (!mddev->parallel_resync
@@ -8819,7 +8819,8 @@ void md_do_sync(struct md_thread *thread)
                                                        desc, mdname(mddev),
                                                        mdname(mddev2));
                                        }
-                                       mddev_put(mddev2);
+                                       spin_unlock(&all_mddevs_lock);
+
                                        if (signal_pending(current))
                                                flush_signals(current);
                                        schedule();
@@ -8829,6 +8830,7 @@ void md_do_sync(struct md_thread *thread)
                                finish_wait(&resync_wait, &wq);
                        }
                }
+               spin_unlock(&all_mddevs_lock);
        } while (mddev->curr_resync < MD_RESYNC_DELAYED);
 
        j = 0;