[PATCH 5 of 8] MD: raid1 changes to allow use by device mapper

MD RAID1: Changes to allow RAID1 to be used by device-mapper (dm-raid.c)

Added the necessary congestion function and conditionalize calls requiring an
array 'queue' or 'gendisk'.

Signed-off-by: Jonathan Brassow

Index: linux-2.6/drivers/md/raid1.c
============================================================ =======
--- linux-2.6.orig/drivers/md/raid1.c
+++ linux-2.6/drivers/md/raid1.c
@@ -497,21 +497,19 @@ static int read_balance(conf_t *conf, r1
return best_disk;
}

-static int raid1_congested(void *data, int bits)
+int md_raid1_congested(mddev_t *mddev, int bits)
{
- mddev_t *mddev = data;
conf_t *conf = mddev->private;
int i, ret = 0;

- if (mddev_congested(mddev, bits))
- return 1;
-
rcu_read_lock();
for (i = 0; i < mddev->raid_disks; i++) {
mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
if (rdev && !test_bit(Faulty, &rdev->flags)) {
struct request_queue *q = bdev_get_queue(rdev->bdev);

+ BUG_ON(!q);
+
/* Note the '|| 1' - when read_balance prefers
* non-congested targets, it can be removed
*/
@@ -524,7 +522,15 @@ static int raid1_congested(void *data, i
rcu_read_unlock();
return ret;
}
+EXPORT_SYMBOL_GPL(md_raid1_congested);

+static int raid1_congested(void *data, int bits)
+{
+ mddev_t *mddev = data;
+
+ return mddev_congested(mddev, bits) ||
+ md_raid1_congested(mddev, bits);
+}

static void flush_pending_writes(conf_t *conf)
{
@@ -1972,6 +1978,8 @@ static int run(mddev_t *mddev)
return PTR_ERR(conf);

list_for_each_entry(rdev, &mddev->disks, same_set) {
+ if (!mddev->gendisk)
+ continue;
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
/* as we don't honour merge_bvec_fn, we must never risk
@@ -2013,8 +2021,10 @@ static int run(mddev_t *mddev)

md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));

- mddev->queue->backing_dev_info.congested_fn = raid1_congested;
- mddev->queue->backing_dev_info.congested_data = mddev;
+ if (mddev->queue) {
+ mddev->queue->backing_dev_info.congested_fn = raid1_congested;
+ mddev->queue->backing_dev_info.congested_data = mddev;
+ }
return md_integrity_register(mddev);
}

Index: linux-2.6/drivers/md/raid1.h
============================================================ =======
--- linux-2.6.orig/drivers/md/raid1.h
+++ linux-2.6/drivers/md/raid1.h
@@ -126,4 +126,6 @@ struct r1bio_s {
*/
#define R1BIO_Returned 6

+extern int md_raid1_congested(mddev_t *mddev, int bits);
+
#endif


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