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From:   Selva Jove <selvajove@gmail.com>
Date:   Mon, 4 Jan 2021 18:12:39 +0530
Message-ID: <CAHqX9vbuq=N0LwH25x6fHajy8Q65dyKyKJhJOksKYW1U3YGHZw@mail.gmail.com>
Subject: Re: [RFC PATCH v4 1/3] block: export bio_map_kern()
To:     Damien Le Moal <Damien.LeMoal@wdc.com>
Cc:     SelvaKumar S <selvakuma.s1@samsung.com>,
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Thanks Damien, Will update that.

On Mon, Jan 4, 2021 at 5:45 PM Damien Le Moal <Damien.LeMoal@wdc.com> wrote:
>
> On 2021/01/04 19:48, SelvaKumar S wrote:
> > Export bio_map_kern() so that copy offload emulation can use
> > it to add vmalloced memory to bio.
> >
> > Signed-off-by: SelvaKumar S <selvakuma.s1@samsung.com>
> > ---
> >  block/blk-map.c        | 3 ++-
> >  include/linux/blkdev.h | 2 ++
> >  2 files changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/block/blk-map.c b/block/blk-map.c
> > index 21630dccac62..50d61475bb68 100644
> > --- a/block/blk-map.c
> > +++ b/block/blk-map.c
> > @@ -378,7 +378,7 @@ static void bio_map_kern_endio(struct bio *bio)
> >   *   Map the kernel address into a bio suitable for io to a block
> >   *   device. Returns an error pointer in case of error.
> >   */
> > -static struct bio *bio_map_kern(struct request_queue *q, void *data,
> > +struct bio *bio_map_kern(struct request_queue *q, void *data,
> >               unsigned int len, gfp_t gfp_mask)
> >  {
> >       unsigned long kaddr = (unsigned long)data;
> > @@ -428,6 +428,7 @@ static struct bio *bio_map_kern(struct request_queue *q, void *data,
> >       bio->bi_end_io = bio_map_kern_endio;
> >       return bio;
> >  }
> > +EXPORT_SYMBOL(bio_map_kern);
>
> Simple copy support is a block layer code, so you I do not think you need this.
> You only need to remove the static declaration of the function.
>
> >
> >  static void bio_copy_kern_endio(struct bio *bio)
> >  {
> > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> > index 070de09425ad..81f9e7bec16c 100644
> > --- a/include/linux/blkdev.h
> > +++ b/include/linux/blkdev.h
> > @@ -936,6 +936,8 @@ extern int blk_rq_map_user(struct request_queue *, struct request *,
> >                          struct rq_map_data *, void __user *, unsigned long,
> >                          gfp_t);
> >  extern int blk_rq_unmap_user(struct bio *);
> > +extern struct bio *bio_map_kern(struct request_queue *q, void *data,
> > +                             unsigned int len, gfp_t gfp_mask);
> >  extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
> >  extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
> >                              struct rq_map_data *, const struct iov_iter *,
> >
>
>
> --
> Damien Le Moal
> Western Digital Research