md/raid submits a lot of IO from the various raid threads.
So adding start/finish plug calls to those so that some
plugging happens.
Signed-off-by: NeilBrown <neilb@suse.de>
        conf_t *conf = mddev->private;
        struct list_head *head = &conf->retry_list;
        mdk_rdev_t *rdev;
+       struct blk_plug plug;
 
        md_check_recovery(mddev);
-       
+
+       blk_start_plug(&plug);
        for (;;) {
                char b[BDEVNAME_SIZE];
 
                }
                cond_resched();
        }
+       blk_finish_plug(&plug);
 }
 
 
 
        conf_t *conf = mddev->private;
        struct list_head *head = &conf->retry_list;
        mdk_rdev_t *rdev;
+       struct blk_plug plug;
 
        md_check_recovery(mddev);
 
+       blk_start_plug(&plug);
        for (;;) {
                char b[BDEVNAME_SIZE];
 
                }
                cond_resched();
        }
+       blk_finish_plug(&plug);
 }
 
 
 
        struct stripe_head *sh;
        raid5_conf_t *conf = mddev->private;
        int handled;
+       struct blk_plug plug;
 
        pr_debug("+++ raid5d active\n");
 
        md_check_recovery(mddev);
 
+       blk_start_plug(&plug);
        handled = 0;
        spin_lock_irq(&conf->device_lock);
        while (1) {
        spin_unlock_irq(&conf->device_lock);
 
        async_tx_issue_pending_all();
+       blk_finish_plug(&plug);
 
        pr_debug("--- raid5d inactive\n");
 }