[PATCH] md: define backing_dev_info.congested_fn for raid0 and linear

Each backing_dev needs to be able to report whether it is congested, either by
modulating BDI_*_congested in ->state, or by defining a ->congested_fn.
md/raid did neither of these.  This patch add a congested_fn which simply
checks all component devices to see if they are congested.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index cb8c6317e4e5..dfe32149ad3a 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -60,6 +60,21 @@ static int raid0_issue_flush(request_queue_t *q, struct gendisk *disk,
         return ret;
 }
 
+static int raid0_congested(void *data, int bits)
+{
+        mddev_t *mddev = data;
+        raid0_conf_t *conf = mddev_to_conf(mddev);
+        mdk_rdev_t **devlist = conf->strip_zone[0].dev;
+        int i, ret = 0;
+
+        for (i = 0; i < mddev->raid_disks && !ret ; i++) {
+                request_queue_t *q = bdev_get_queue(devlist[i]->bdev);
+
+                ret |= bdi_congested(&q->backing_dev_info, bits);
+        }
+        return ret;
+}
+
 
 static int create_strip_zones (mddev_t *mddev)
 {
@@ -236,6 +251,8 @@ static int create_strip_zones (mddev_t *mddev)
         mddev->queue->unplug_fn = raid0_unplug;
 
         mddev->queue->issue_flush_fn = raid0_issue_flush;
+        mddev->queue->backing_dev_info.congested_fn = raid0_congested;
+        mddev->queue->backing_dev_info.congested_data = mddev;
 
         printk("raid0: done.\n");
         return 0;