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: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2010-06-01 19:37:28 +10:00
parent 768a418db1
commit 4a5add4995

View File

@ -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);