[Drbd-dev] [PATCH 3/7] rnbd: drop WRITE_SAME support

[Jinpu Wang]

On Wed, Feb 9, 2022 at 10:05 AM Guoqing Jiang <guoqing.jiang at linux.dev> wrote:
>
>
>
> On 2/9/22 4:28 PM, Christoph Hellwig 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.
> >
> > Signed-off-by: Christoph Hellwig<hch at 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;
>
> I am planning to remove more members inside struct rnbd_clt_dev.
>
> > 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;
>
> 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.

The patch looks good to me, but I want to run a regression test before
give an acked.

Thanks!
Jinpu
>
> Thanks,
> Guoqing