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To:     SelvaKumar S <selvakuma.s1@samsung.com>,
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Subject: Re: [RFC PATCH v3 1/2] block: add simple copy support
Thread-Topic: [RFC PATCH v3 1/2] block: add simple copy support
Thread-Index: AQHWz83y7bUu+jQhLUujuAOdfzAPcw==
Date:   Fri, 11 Dec 2020 16:25:57 +0000
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On 11/12/2020 15:57, SelvaKumar S wrote:=0A=
[...] =0A=
> +int blk_copy_emulate(struct block_device *bdev, struct blk_copy_payload =
*payload,=0A=
> +		gfp_t gfp_mask)=0A=
> +{=0A=
> +	struct request_queue *q =3D bdev_get_queue(bdev);=0A=
> +	struct bio *bio;=0A=
> +	void *buf =3D NULL;=0A=
> +	int i, nr_srcs, max_range_len, ret, cur_dest, cur_size;=0A=
> +=0A=
> +	nr_srcs =3D payload->copy_range;=0A=
> +	max_range_len =3D q->limits.max_copy_range_sectors << SECTOR_SHIFT;=0A=
> +	cur_dest =3D payload->dest;=0A=
> +	buf =3D kvmalloc(max_range_len, GFP_ATOMIC);=0A=
=0A=
Why GFP_ATOMIC and not the passed in gfp_mask? Especially as this is a kvma=
lloc()=0A=
which has the potential to grow quite big.=0A=
=0A=
> +int __blkdev_issue_copy(struct block_device *bdev, sector_t dest,=0A=
> +		sector_t nr_srcs, struct range_entry *rlist, gfp_t gfp_mask,=0A=
> +		int flags, struct bio **biop)=0A=
> +{=0A=
=0A=
[...]=0A=
=0A=
> +	total_size =3D struct_size(payload, range, nr_srcs);=0A=
> +	payload =3D kmalloc(total_size, GFP_ATOMIC | __GFP_NOWARN);=0A=
=0A=
Same here. =0A=
=0A=
=0A=
> diff --git a/block/ioctl.c b/block/ioctl.c=0A=
> index 6b785181344f..a4a507d85e56 100644=0A=
> --- a/block/ioctl.c=0A=
> +++ b/block/ioctl.c=0A=
> @@ -142,6 +142,47 @@ static int blk_ioctl_discard(struct block_device *bd=
ev, fmode_t mode,=0A=
>  				    GFP_KERNEL, flags);=0A=
>  }=0A=
>  =0A=
> +static int blk_ioctl_copy(struct block_device *bdev, fmode_t mode,=0A=
> +		unsigned long arg, unsigned long flags)=0A=
> +{=0A=
=0A=
[...]=0A=
=0A=
> +=0A=
> +	rlist =3D kmalloc_array(crange.nr_range, sizeof(*rlist),=0A=
> +			GFP_ATOMIC | __GFP_NOWARN);=0A=
=0A=
And here. I think this one can even be GFP_KERNEL.=0A=
=0A=
 =0A=
=0A=