[3/7] rnbd: drop WRITE_SAME support

REQ_OP_WRITE_SAME was only ever submitted by the legacy Linux zeroing
code, which has switched to use REQ_OP_WRITE_ZEROES long before rnbd was
even merged.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/rnbd/rnbd-clt.c   | 7 ++-----
 drivers/block/rnbd/rnbd-clt.h   | 1 -
 drivers/block/rnbd/rnbd-proto.h | 6 ------
 drivers/block/rnbd/rnbd-srv.c   | 3 +--
 4 files changed, 3 insertions(+), 14 deletions(-)

On 2/9/22 5:13 PM, Jinpu Wang wrote:
>>> --- a/drivers/block/rnbd/rnbd-srv.c
>>> +++ b/drivers/block/rnbd/rnbd-srv.c
>>> @@ -548,8 +548,7 @@ static void rnbd_srv_fill_msg_open_rsp(struct rnbd_msg_open_rsp *rsp,
>>>                cpu_to_le16(rnbd_dev_get_max_segs(rnbd_dev));
>>>        rsp->max_hw_sectors =
>>>                cpu_to_le32(rnbd_dev_get_max_hw_sects(rnbd_dev));
>>> -     rsp->max_write_same_sectors =
>>> -             cpu_to_le32(bdev_write_same(rnbd_dev->bdev));
>>> +     rsp->max_write_same_sectors = 0;
>> IIUC, I think we can delete max_write_same_sectors from rsp as well given
>> the earlier change in setup_request_queue and rnbd_clt_set_dev_attr.
> No, I don't think it's a good idea, we need to keep the protocol
> compatible, so client for old kernel version
> won't be confused.

Fair enough. Then I guess it is better to add obsolete_ prefix like 
obsolete_rotational.

Thanks,
Guoqing

Hi Christoph,


On Wed, Feb 9, 2022 at 9:28 AM Christoph Hellwig <hch@lst.de> wrote:
>
> REQ_OP_WRITE_SAME was only ever submitted by the legacy Linux zeroing
> code, which has switched to use REQ_OP_WRITE_ZEROES long before rnbd was
> even merged.

Do you think if it makes sense to instead of removing
REQ_OP_WRITE_SAME, simply convert it to REQ_OP_WRITE_ZEROES?

Thanks!
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/block/rnbd/rnbd-clt.c   | 7 ++-----
>  drivers/block/rnbd/rnbd-clt.h   | 1 -
>  drivers/block/rnbd/rnbd-proto.h | 6 ------
>  drivers/block/rnbd/rnbd-srv.c   | 3 +--
>  4 files changed, 3 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/block/rnbd/rnbd-clt.c b/drivers/block/rnbd/rnbd-clt.c
> index c08971de369fc..dc192d2738854 100644
> --- a/drivers/block/rnbd/rnbd-clt.c
> +++ b/drivers/block/rnbd/rnbd-clt.c
> @@ -82,7 +82,6 @@ static int rnbd_clt_set_dev_attr(struct rnbd_clt_dev *dev,
>         dev->nsectors               = le64_to_cpu(rsp->nsectors);
>         dev->logical_block_size     = le16_to_cpu(rsp->logical_block_size);
>         dev->physical_block_size    = le16_to_cpu(rsp->physical_block_size);
> -       dev->max_write_same_sectors = le32_to_cpu(rsp->max_write_same_sectors);
>         dev->max_discard_sectors    = le32_to_cpu(rsp->max_discard_sectors);
>         dev->discard_granularity    = le32_to_cpu(rsp->discard_granularity);
>         dev->discard_alignment      = le32_to_cpu(rsp->discard_alignment);
> @@ -1359,8 +1358,6 @@ static void setup_request_queue(struct rnbd_clt_dev *dev)
>         blk_queue_logical_block_size(dev->queue, dev->logical_block_size);
>         blk_queue_physical_block_size(dev->queue, dev->physical_block_size);
>         blk_queue_max_hw_sectors(dev->queue, dev->max_hw_sectors);
> -       blk_queue_max_write_same_sectors(dev->queue,
> -                                        dev->max_write_same_sectors);
>
>         /*
>          * we don't support discards to "discontiguous" segments
> @@ -1610,10 +1607,10 @@ struct rnbd_clt_dev *rnbd_clt_map_device(const char *sessname,
>         }
>
>         rnbd_clt_info(dev,
> -                      "map_device: Device mapped as %s (nsectors: %zu, logical_block_size: %d, physical_block_size: %d, max_write_same_sectors: %d, max_discard_sectors: %d, discard_granularity: %d, discard_alignment: %d, secure_discard: %d, max_segments: %d, max_hw_sectors: %d, rotational: %d, wc: %d, fua: %d)\n",
> +                      "map_device: Device mapped as %s (nsectors: %zu, logical_block_size: %d, physical_block_size: %d, max_discard_sectors: %d, discard_granularity: %d, discard_alignment: %d, secure_discard: %d, max_segments: %d, max_hw_sectors: %d, rotational: %d, wc: %d, fua: %d)\n",
>                        dev->gd->disk_name, dev->nsectors,
>                        dev->logical_block_size, dev->physical_block_size,
> -                      dev->max_write_same_sectors, dev->max_discard_sectors,
> +                      dev->max_discard_sectors,
>                        dev->discard_granularity, dev->discard_alignment,
>                        dev->secure_discard, dev->max_segments,
>                        dev->max_hw_sectors, dev->rotational, dev->wc, dev->fua);
> diff --git a/drivers/block/rnbd/rnbd-clt.h b/drivers/block/rnbd/rnbd-clt.h
> index 0c2cae7f39b9f..6946ba23d62e5 100644
> --- a/drivers/block/rnbd/rnbd-clt.h
> +++ b/drivers/block/rnbd/rnbd-clt.h
> @@ -122,7 +122,6 @@ struct rnbd_clt_dev {
>         bool                    wc;
>         bool                    fua;
>         u32                     max_hw_sectors;
> -       u32                     max_write_same_sectors;
>         u32                     max_discard_sectors;
>         u32                     discard_granularity;
>         u32                     discard_alignment;
> diff --git a/drivers/block/rnbd/rnbd-proto.h b/drivers/block/rnbd/rnbd-proto.h
> index de5d5a8df81d7..3eb8b34bd1886 100644
> --- a/drivers/block/rnbd/rnbd-proto.h
> +++ b/drivers/block/rnbd/rnbd-proto.h
> @@ -249,9 +249,6 @@ static inline u32 rnbd_to_bio_flags(u32 rnbd_opf)
>         case RNBD_OP_SECURE_ERASE:
>                 bio_opf = REQ_OP_SECURE_ERASE;
>                 break;
> -       case RNBD_OP_WRITE_SAME:
> -               bio_opf = REQ_OP_WRITE_SAME;
> -               break;
>         default:
>                 WARN(1, "Unknown RNBD type: %d (flags %d)\n",
>                      rnbd_op(rnbd_opf), rnbd_opf);
> @@ -284,9 +281,6 @@ static inline u32 rq_to_rnbd_flags(struct request *rq)
>         case REQ_OP_SECURE_ERASE:
>                 rnbd_opf = RNBD_OP_SECURE_ERASE;
>                 break;
> -       case REQ_OP_WRITE_SAME:
> -               rnbd_opf = RNBD_OP_WRITE_SAME;
> -               break;
>         case REQ_OP_FLUSH:
>                 rnbd_opf = RNBD_OP_FLUSH;
>                 break;
> diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
> index 132e950685d59..0e6b5687f8321 100644
> --- a/drivers/block/rnbd/rnbd-srv.c
> +++ b/drivers/block/rnbd/rnbd-srv.c
> @@ -548,8 +548,7 @@ static void rnbd_srv_fill_msg_open_rsp(struct rnbd_msg_open_rsp *rsp,
>                 cpu_to_le16(rnbd_dev_get_max_segs(rnbd_dev));
>         rsp->max_hw_sectors =
>                 cpu_to_le32(rnbd_dev_get_max_hw_sects(rnbd_dev));
> -       rsp->max_write_same_sectors =
> -               cpu_to_le32(bdev_write_same(rnbd_dev->bdev));
> +       rsp->max_write_same_sectors = 0;
>         rsp->max_discard_sectors =
>                 cpu_to_le32(rnbd_dev_get_max_discard_sects(rnbd_dev));
>         rsp->discard_granularity =
> --
> 2.30.2
>

On Wed, Feb 9, 2022 at 3:04 PM Christoph Hellwig <hch@lst.de> wrote:
>
> On Wed, Feb 09, 2022 at 11:16:13AM +0100, Jinpu Wang wrote:
> > Hi Christoph,
> >
> >
> > On Wed, Feb 9, 2022 at 9:28 AM Christoph Hellwig <hch@lst.de> wrote:
> > >
> > > REQ_OP_WRITE_SAME was only ever submitted by the legacy Linux zeroing
> > > code, which has switched to use REQ_OP_WRITE_ZEROES long before rnbd was
> > > even merged.
> >
> > Do you think if it makes sense to instead of removing
> > REQ_OP_WRITE_SAME, simply convert it to REQ_OP_WRITE_ZEROES?
>
> Well, they have different semantics, so you can't just "convert" it.
> But it might make sense to add REQ_OP_WRITE_ZEROES.
Thanks, we will add support for REQ_OP_WRITE_ZEROES later.

For this patch, I've run internal tests, works fine.

Acked-by: Jack Wang <jinpu.wang@ionos.com>
Thanks!