linux-kernel - Re: [PATCH 07/16] rbd: use memzero

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Message-ID: <CAOi1vP-zSAnx5z7EbPNVLoCHWdK5iGjXU7KKrRL8YZF1QfMf3A@mail.gmail.com>
Date:   Wed, 9 Jun 2021 11:37:45 +0200
From:   Ilya Dryomov <idryomov@...il.com>
To:     Christoph Hellwig <hch@....de>
Cc:     Jens Axboe <axboe@...nel.dk>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Geoff Levand <geoff@...radead.org>,
        Dongsheng Yang <dongsheng.yang@...ystack.cn>,
        Mike Snitzer <snitzer@...hat.com>,
        Ira Weiny <ira.weiny@...el.com>, dm-devel@...hat.com,
        linux-mips@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
        linux-block <linux-block@...r.kernel.org>,
        linuxppc-dev@...ts.ozlabs.org,
        Ceph Development <ceph-devel@...r.kernel.org>
Subject: Re: [PATCH 07/16] rbd: use memzero_bvec

On Tue, Jun 8, 2021 at 6:06 PM Christoph Hellwig <hch@....de> wrote:
>
> Use memzero_bvec instead of reimplementing it.
>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
>  drivers/block/rbd.c | 15 ++-------------
>  1 file changed, 2 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index bbb88eb009e0..eb243fc4d108 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -1219,24 +1219,13 @@ static void rbd_dev_mapping_clear(struct rbd_device *rbd_dev)
>         rbd_dev->mapping.size = 0;
>  }
>
> -static void zero_bvec(struct bio_vec *bv)
> -{
> -       void *buf;
> -       unsigned long flags;
> -
> -       buf = bvec_kmap_irq(bv, &flags);
> -       memset(buf, 0, bv->bv_len);
> -       flush_dcache_page(bv->bv_page);
> -       bvec_kunmap_irq(buf, &flags);
> -}
> -
>  static void zero_bios(struct ceph_bio_iter *bio_pos, u32 off, u32 bytes)
>  {
>         struct ceph_bio_iter it = *bio_pos;
>
>         ceph_bio_iter_advance(&it, off);
>         ceph_bio_iter_advance_step(&it, bytes, ({
> -               zero_bvec(&bv);
> +               memzero_bvec(&bv);
>         }));
>  }
>
> @@ -1246,7 +1235,7 @@ static void zero_bvecs(struct ceph_bvec_iter *bvec_pos, u32 off, u32 bytes)
>
>         ceph_bvec_iter_advance(&it, off);
>         ceph_bvec_iter_advance_step(&it, bytes, ({
> -               zero_bvec(&bv);
> +               memzero_bvec(&bv);
>         }));
>  }
>

Ira already brought up the fact that this conversion drops
flush_dcache_page() calls throughout.  Other than that:

Acked-by: Ilya Dryomov <idryomov@...il.com>

Thanks,

                Ilya