md/plug: optionally use plugger to unplug an array during resync/recovery.

If an array doesn't have a 'queue' then md_do_sync cannot
unplug it.
In that case it will have a 'plugger', so make that available
to the mddev, and use it to unplug the array if needed.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index eec75f1..03c64e9 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4693,6 +4693,7 @@ static void md_clean(mddev_t *mddev)
        mddev->bitmap_info.chunksize = 0;
        mddev->bitmap_info.daemon_sleep = 0;
        mddev->bitmap_info.max_write_behind = 0;
+       mddev->plug = NULL;
 }
 
 void md_stop_writes(mddev_t *mddev)
@@ -6626,6 +6627,14 @@ int md_allow_write(mddev_t *mddev)
 }
 EXPORT_SYMBOL_GPL(md_allow_write);
 
+static void md_unplug(mddev_t *mddev)
+{
+       if (mddev->queue)
+               blk_unplug(mddev->queue);
+       if (mddev->plug)
+               mddev->plug->unplug_fn(mddev->plug);
+}
+
 #define SYNC_MARKS     10
 #define        SYNC_MARK_STEP  (3*HZ)
 void md_do_sync(mddev_t *mddev)
@@ -6804,7 +6813,7 @@ void md_do_sync(mddev_t *mddev)
                     >= mddev->resync_max - mddev->curr_resync_completed
                            )) {
                        /* time to update curr_resync_completed */
-                       blk_unplug(mddev->queue);
+                       md_unplug(mddev);
                        wait_event(mddev->recovery_wait,
                                   atomic_read(&mddev->recovery_active) == 0);
                        mddev->curr_resync_completed =
@@ -6882,7 +6891,7 @@ void md_do_sync(mddev_t *mddev)
                 * about not overloading the IO subsystem. (things like an
                 * e2fsck being done on the RAID array should execute fast)
                 */
-               blk_unplug(mddev->queue);
+               md_unplug(mddev);
                cond_resched();
 
                currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
@@ -6901,7 +6910,7 @@ void md_do_sync(mddev_t *mddev)
         * this also signals 'finished resyncing' to md_stop
         */
  out:
-       blk_unplug(mddev->queue);
+       md_unplug(mddev);
 
        wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
 

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 5be0d69..57eb864 100644 (file)
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -328,6 +328,8 @@ struct mddev_s
        struct list_head                all_mddevs;
 
        struct attribute_group          *to_remove;
+       struct plug_handle              *plug; /* if used by personality */
+
        /* Generic barrier handling.
         * If there is a pending barrier request, all other
         * writes are blocked while the devices are flushed.

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 84bb9ae..0a8173e 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5189,6 +5189,7 @@ static int run(mddev_t *mddev)
        md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
 
        plugger_init(&conf->plug, raid5_unplug);
+       mddev->plug = &conf->plug;
        if (mddev->queue) {
                /* read-ahead size must cover two whole stripes, which
                 * is 2 * (datadisks) * chunksize where 'n' is the