Re: [PATCH 03/12] drbd: remove RB_CONGESTED_REMOTE

Jan Kara
2020-09-17T09:55:17Z

On Thu 10-09-20 16:48:23, Christoph Hellwig wrote:
> This case isn't ever used.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Are you sure it's never used? As far as I'm reading drdb code the contents
of the disk_conf structure seems to be received through netlink (that code
is really a macro hell) and so read_balancing attribute passed to
remote_due_to_read_balancing() can have any value userspace passed to it.

Honza

> ---
> drivers/block/drbd/drbd_req.c | 4 ----
> include/linux/drbd.h | 1 -
> 2 files changed, 5 deletions(-)
>
> diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
> index 5c975af9c15fb8..481bc34fcf386a 100644
> --- a/drivers/block/drbd/drbd_req.c
> +++ b/drivers/block/drbd/drbd_req.c
> @@ -901,13 +901,9 @@ static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector,
> static bool remote_due_to_read_balancing(struct drbd_device *device, sector_t sector,
> enum drbd_read_balancing rbm)
> {
> - struct backing_dev_info *bdi;
> int stripe_shift;
>
> switch (rbm) {
> - case RB_CONGESTED_REMOTE:
> - bdi = device->ldev->backing_bdev->bd_disk->queue->backing_dev_info;
> - return bdi_read_congested(bdi);
> case RB_LEAST_PENDING:
> return atomic_read(&device->local_cnt) >
> atomic_read(&device->ap_pending_cnt) + atomic_read(&device->rs_pending_cnt);
> diff --git a/include/linux/drbd.h b/include/linux/drbd.h
> index 5755537b51b114..6a8286132751df 100644
> --- a/include/linux/drbd.h
> +++ b/include/linux/drbd.h
> @@ -94,7 +94,6 @@ enum drbd_read_balancing {
> RB_PREFER_REMOTE,
> RB_ROUND_ROBIN,
> RB_LEAST_PENDING,
> - RB_CONGESTED_REMOTE,
> RB_32K_STRIPING,
> RB_64K_STRIPING,
> RB_128K_STRIPING,
> --
> 2.28.0
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR