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Commit 4a5add49 authored by NeilBrown's avatar NeilBrown
Browse files

raid5: Don't set read-ahead when there is no queue 



dm-raid456 does not provide a 'queue' for raid5 to use,
so we must make raid5 stop depending on the queue.

First: read_ahead
dm handles read-ahead adjustment fully in userspace, so
simply don't do any readahead adjustments if there is
no queue.

Also re-arrange code slightly so all the accesses to ->queue are
together.

Finally, move the blk_queue_merge_bvec function into the 'if' as
the ->split_io setting in dm-raid456 has the same effect.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 768a418d

drivers/md/raid5.c

+17 −15
Original line number Diff line number Diff line
@@ -5161,16 +5161,6 @@ static int run(mddev_t *mddev) 
							"reshape");

	}



	/* read-ahead size must cover two whole stripes, which is

	 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices

	 */

	{

		int data_disks = conf->previous_raid_disks - conf->max_degraded;

		int stripe = data_disks *

			((mddev->chunk_sectors << 9) / PAGE_SIZE);

		if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)

			mddev->queue->backing_dev_info.ra_pages = 2 * stripe;

	}



	/* Ok, everything is just fine now */

	if (mddev->to_remove == &raid5_attrs_group)
@@ -5178,8 +5168,23 @@ static int run(mddev_t *mddev) 
	else if (mddev->kobj.sd &&

	    sysfs_create_group(&mddev->kobj, &raid5_attrs_group))

		printk(KERN_WARNING

		       "md/raid:%s: failed to create sysfs attributes.\n",

		       "raid5: failed to create sysfs attributes for %s\n",

		       mdname(mddev));

	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));



	if (mddev->queue) {

		/* read-ahead size must cover two whole stripes, which

		 * is 2 * (datadisks) * chunksize where 'n' is the

		 * number of raid devices

		 */

		int data_disks = conf->previous_raid_disks - conf->max_degraded;

		int stripe = data_disks *

			((mddev->chunk_sectors << 9) / PAGE_SIZE);

		if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)

			mddev->queue->backing_dev_info.ra_pages = 2 * stripe;



		blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);

	}



	mddev->queue->queue_lock = &conf->device_lock;
@@ -5187,9 +5192,6 @@ static int run(mddev_t *mddev) 
	mddev->queue->backing_dev_info.congested_data = mddev;

	mddev->queue->backing_dev_info.congested_fn = raid5_congested;



	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));



	blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);

	chunk_size = mddev->chunk_sectors << 9;

	blk_queue_io_min(mddev->queue, chunk_size);

	blk_queue_io_opt(mddev->queue, chunk_size *
@@ -5618,7 +5620,7 @@ static void end_reshape(raid5_conf_t *conf) 
		/* read-ahead size must cover two whole stripes, which is

		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices

		 */

		{

		if (conf->mddev->queue) {

			int data_disks = conf->raid_disks - conf->max_degraded;

			int stripe = data_disks * ((conf->chunk_sectors << 9)

						   / PAGE_SIZE);