[dm-devel] dm: fix congested_fn for request-based device
Mike Snitzer
snitzer at redhat.com
Tue Mar 3 16:15:35 UTC 2020
On Tue, Mar 03 2020 at 3:45am -0500,
Hou Tao <houtao1 at huawei.com> wrote:
> We neither assign congested_fn for requested-based blk-mq device
> nor implement it correctly. So fix both.
>
> Fixes: 4aa9c692e052 ("bdi: separate out congested state into a separate struct")
> Signed-off-by: Hou Tao <houtao1 at huawei.com>
> ---
> drivers/md/dm.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index b89f07ee2eff..80b95e21db43 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -1784,11 +1784,13 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
>
> if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
> if (dm_request_based(md)) {
> + struct backing_dev_info *bdi =
> + md->queue->backing_dev_info;
> /*
> * With request-based DM we only need to check the
> * top-level queue for congestion.
> */
> - r = md->queue->backing_dev_info->wb.state & bdi_bits;
> + r = bdi->wb.congested->state & bdi_bits;
> } else {
> map = dm_get_live_table_fast(md);
> if (map)
The above change does indeed fix missing conversion that should've
occurred in commit 4aa9c692e052.
> @@ -2265,6 +2267,7 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
> DMERR("Cannot initialize queue for request-based dm-mq mapped device");
> return r;
> }
> + dm_init_normal_md_queue(md);
> break;
> case DM_TYPE_BIO_BASED:
> case DM_TYPE_DAX_BIO_BASED:
I've renamed dm_init_normal_md_queue to dm_init_congested_fn and removed
it's incorrect comment.
Here is the final fix I just staged:
https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-5.6&id=974f51e8633f0f3f33e8f86bbb5ae66758aa63c7
Thanks,
Mike
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