On Tue, Nov 15 2016 at 6:33pm -0500,
Bart Van Assche <bart.vanassche@xxxxxxxxxxx> wrote:
> Use a single loop instead of two loops to determine whether or not
> all_blk_mq has to be set.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> ---
> drivers/md/dm-table.c | 25 ++++++++++++-------------
> 1 file changed, 12 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index 49893fdc..fff4979 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -871,7 +871,7 @@ static int dm_table_determine_type(struct dm_table *t)
> {
> unsigned i;
> unsigned bio_based = 0, request_based = 0, hybrid = 0;
> - bool verify_blk_mq = false;
> + unsigned sq_count = 0, mq_count = 0;
> struct dm_target *tgt;
> struct dm_dev_internal *dd;
> struct list_head *devices = dm_table_get_devices(t);
> @@ -959,20 +959,15 @@ static int dm_table_determine_type(struct dm_table *t)
> }
>
> if (q->mq_ops)
> - verify_blk_mq = true;
> + mq_count++;
> + else
> + sq_count++;
> }
> -
> - if (verify_blk_mq) {
> - /* verify _all_ devices in the table are blk-mq devices */
> - list_for_each_entry(dd, devices, list)
> - if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
> - DMERR("table load rejected: not all devices"
> - " are blk-mq request-stackable");
> - return -EINVAL;
> - }
> -
> - t->all_blk_mq = true;
> + if (sq_count && mq_count) {
> + DMERR("table load rejected: not all devices are blk-mq request-stackable");
> + return -EINVAL;
> }
> + t->all_blk_mq = mq_count > 0;
>
> return 0;
> }
> @@ -1021,6 +1016,10 @@ bool dm_table_request_based(struct dm_table *t)
> return __table_type_request_based(dm_table_get_type(t));
> }
>
> +/*
> + * Returns true if all paths are blk-mq devices. Returns false if all paths
> + * are single queue block devices or if there are no paths.
> + */
This code isn't specific to multipath. So "paths" is misplaced.
"devices" is more appropriate. Not seeing the need for the comment to
be honest. The function name is pretty descriptive.
> bool dm_table_all_blk_mq_devices(struct dm_table *t)
> {
> return t->all_blk_mq;
> --
> 2.10.1
>
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