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From:   Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
To:     Chaitanya Kulkarni <chaitanyak@nvidia.com>
CC:     "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "axboe@kernel.dk" <axboe@kernel.dk>,
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        "bvanassche@acm.org" <bvanassche@acm.org>,
        "vincent.fu@samsung.com" <vincent.fu@samsung.com>
Subject: Re: [PATCH V4 1/8] null_blk: allow REQ_OP_WRITE_ZEROES
Thread-Topic: [PATCH V4 1/8] null_blk: allow REQ_OP_WRITE_ZEROES
Thread-Index: AQHZBEpV3/vIPNnSTUWn9aHpK6AE0a5XGscAgAEDsACAAB9SAA==
Date:   Thu, 1 Dec 2022 01:21:08 +0000
Message-ID: <20221201012106.wrultudwilepwmnt@shindev>
References: <20221129232813.37968-1-kch@nvidia.com>
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On Nov 30, 2022 / 23:29, Chaitanya Kulkarni wrote:
> >> Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
> >=20
> > This motivation sounds good. I tried this patch. With a quick test it l=
ooks
> > working good for me. Please find minor comments in line.
> >=20
> > [...]
> >=20
> >> +static void null_zero_sector(struct nullb_device *d, sector_t sect,
> >> +			     sector_t nr_sects, bool cache)
> >> +{
> >> +	struct radix_tree_root *root =3D cache ? &d->cache : &d->data;
> >> +	struct nullb_page *t_page;
> >> +	unsigned int offset;
> >> +	void *dest;
> >> +
> >> +	t_page =3D radix_tree_lookup(root, sect >> PAGE_SECTORS_SHIFT);
> >> +	if (!t_page)
> >> +		return;
> >> +
> >> +	offset =3D (sect & SECTOR_MASK) << SECTOR_SHIFT;
> >> +	dest =3D kmap_atomic(t_page->page);
> >> +	memset(dest + offset, 0, SECTOR_SIZE * nr_sects);
> >> +	kunmap_atomic(dest);
> >> +}
> >=20
> > Did you consider to call null_lookup_page() for __null_lookup_page() fr=
om
> > null_zero_sector()? It may simplify this function a bit.
> >=20
>=20
> I found this clear and easy than going over call chain when
> debugging.

Okay, then the patch looks good to me :)

Reviewed-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>

--=20
Shin'ichiro Kawasaki=