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From:   Damien Le Moal <Damien.LeMoal@wdc.com>
To:     SelvaKumar S <selvakuma.s1@samsung.com>,
        "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
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Subject: Re: [RFC PATCH v4 1/3] block: export bio_map_kern()
Thread-Topic: [RFC PATCH v4 1/3] block: export bio_map_kern()
Thread-Index: AQHW4ocU0RUveu4eRki+HX4FIJ17pA==
Date:   Mon, 4 Jan 2021 12:15:38 +0000
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On 2021/01/04 19:48, SelvaKumar S wrote:=0A=
> Export bio_map_kern() so that copy offload emulation can use=0A=
> it to add vmalloced memory to bio.=0A=
> =0A=
> Signed-off-by: SelvaKumar S <selvakuma.s1@samsung.com>=0A=
> ---=0A=
>  block/blk-map.c        | 3 ++-=0A=
>  include/linux/blkdev.h | 2 ++=0A=
>  2 files changed, 4 insertions(+), 1 deletion(-)=0A=
> =0A=
> diff --git a/block/blk-map.c b/block/blk-map.c=0A=
> index 21630dccac62..50d61475bb68 100644=0A=
> --- a/block/blk-map.c=0A=
> +++ b/block/blk-map.c=0A=
> @@ -378,7 +378,7 @@ static void bio_map_kern_endio(struct bio *bio)=0A=
>   *	Map the kernel address into a bio suitable for io to a block=0A=
>   *	device. Returns an error pointer in case of error.=0A=
>   */=0A=
> -static struct bio *bio_map_kern(struct request_queue *q, void *data,=0A=
> +struct bio *bio_map_kern(struct request_queue *q, void *data,=0A=
>  		unsigned int len, gfp_t gfp_mask)=0A=
>  {=0A=
>  	unsigned long kaddr =3D (unsigned long)data;=0A=
> @@ -428,6 +428,7 @@ static struct bio *bio_map_kern(struct request_queue =
*q, void *data,=0A=
>  	bio->bi_end_io =3D bio_map_kern_endio;=0A=
>  	return bio;=0A=
>  }=0A=
> +EXPORT_SYMBOL(bio_map_kern);=0A=
=0A=
Simple copy support is a block layer code, so you I do not think you need t=
his.=0A=
You only need to remove the static declaration of the function.=0A=
=0A=
>  =0A=
>  static void bio_copy_kern_endio(struct bio *bio)=0A=
>  {=0A=
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h=0A=
> index 070de09425ad..81f9e7bec16c 100644=0A=
> --- a/include/linux/blkdev.h=0A=
> +++ b/include/linux/blkdev.h=0A=
> @@ -936,6 +936,8 @@ extern int blk_rq_map_user(struct request_queue *, st=
ruct request *,=0A=
>  			   struct rq_map_data *, void __user *, unsigned long,=0A=
>  			   gfp_t);=0A=
>  extern int blk_rq_unmap_user(struct bio *);=0A=
> +extern struct bio *bio_map_kern(struct request_queue *q, void *data,=0A=
> +				unsigned int len, gfp_t gfp_mask);=0A=
>  extern int blk_rq_map_kern(struct request_queue *, struct request *, voi=
d *, unsigned int, gfp_t);=0A=
>  extern int blk_rq_map_user_iov(struct request_queue *, struct request *,=
=0A=
>  			       struct rq_map_data *, const struct iov_iter *,=0A=
> =0A=
=0A=
=0A=
-- =0A=
Damien Le Moal=0A=
Western Digital Research=0A=