> On Apr 17, 2015, at 7:39 AM, heinzm@xxxxxxxxxx wrote:
>
> From: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
>
> This patch is a prerequisite for dm-raid "raid0" support to allow
> dm-raid to access the MD RAID0 personality doing unconditional
> accesses to mddev->queue, which is NULL in case of dm-raid stacked
> on top of MD.
>
> This patch is here for completeness; it has been send to Neil Brown
> and linux-raid, Neil said he applied it on Feb 23rd but it did not
> show up in upstream as yet.
>
>
> Signed-off-by: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
> Tested-by: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
>
> ---
> drivers/md/raid0.c | 48 +++++++++++++++++++++++++++---------------------
> 1 file changed, 27 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index 3ed9f42..e074813 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -271,14 +271,16 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
> goto abort;
> }
>
> - blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
> - blk_queue_io_opt(mddev->queue,
> - (mddev->chunk_sectors << 9) * mddev->raid_disks);
> -
> - if (!discard_supported)
> - queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
> - else
> - queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
> + if (mddev->queue) {
> + blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
> + blk_queue_io_opt(mddev->queue,
> + (mddev->chunk_sectors << 9) * mddev->raid_disks);
> +
> + if (!discard_supported)
> + queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
> + else
> + queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
> + }
>
> pr_debug("md/raid0:%s: done.\n", mdname(mddev));
> *private_conf = conf;
> @@ -429,9 +431,12 @@ static int raid0_run(struct mddev *mddev)
> }
> if (md_check_no_bitmap(mddev))
> return -EINVAL;
> - blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
> - blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
> - blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);
> +
> + if (mddev->queue) {
> + blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
> + blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
> + blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);
> + }
>
> /* if private is not null, we are here after takeover */
> if (mddev->private == NULL) {
> @@ -448,16 +453,17 @@ static int raid0_run(struct mddev *mddev)
> printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
> mdname(mddev),
> (unsigned long long)mddev->array_sectors);
> - /* calculate the max read-ahead size.
> - * For read-ahead of large files to be effective, we need to
> - * readahead at least twice a whole stripe. i.e. number of devices
> - * multiplied by chunk size times 2.
> - * If an individual device has an ra_pages greater than the
> - * chunk size, then we will not drive that device as hard as it
> - * wants. We consider this a configuration error: a larger
> - * chunksize should be used in that case.
> - */
> - {
> +
> + if (mddev->queue) {
> + /* calculate the max read-ahead size.
> + * For read-ahead of large files to be effective, we need to
> + * readahead at least twice a whole stripe. i.e. number of devices
> + * multiplied by chunk size times 2.
> + * If an individual device has an ra_pages greater than the
> + * chunk size, then we will not drive that device as hard as it
> + * wants. We consider this a configuration error: a larger
> + * chunksize should be used in that case.
> + */
> int stripe = mddev->raid_disks *
> (mddev->chunk_sectors << 9) / PAGE_SIZE;
> if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
fold in with conditionalization of gendisk structure?
brassow
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