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From:   Ralph Campbell <rcampbell@nvidia.com>
To:     Alistair Popple <apopple@nvidia.com>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "nouveau@lists.freedesktop.org" <nouveau@lists.freedesktop.org>,
        "bskeggs@redhat.com" <bskeggs@redhat.com>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>
CC:     "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        "John Hubbard" <jhubbard@nvidia.com>,
        "jglisse@redhat.com" <jglisse@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        "hch@infradead.org" <hch@infradead.org>,
        "daniel@ffwll.ch" <daniel@ffwll.ch>
Subject: RE: [PATCH v3 6/8] mm: Selftests for exclusive device memory
Thread-Topic: [PATCH v3 6/8] mm: Selftests for exclusive device memory
Thread-Index: AQHXDA+10DMlRgXFfUuy1T9vHkceyqpvyHZQ
Date:   Mon, 1 Mar 2021 23:14:56 +0000
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References: <20210226071832.31547-1-apopple@nvidia.com>
 <20210226071832.31547-7-apopple@nvidia.com>
In-Reply-To: <20210226071832.31547-7-apopple@nvidia.com>
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> From: Alistair Popple <apopple@nvidia.com>
> Sent: Thursday, February 25, 2021 11:19 PM
> To: linux-mm@kvack.org; nouveau@lists.freedesktop.org;
> bskeggs@redhat.com; akpm@linux-foundation.org
> Cc: linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org; dri-
> devel@lists.freedesktop.org; John Hubbard <jhubbard@nvidia.com>; Ralph
> Campbell <rcampbell@nvidia.com>; jglisse@redhat.com; Jason Gunthorpe
> <jgg@nvidia.com>; hch@infradead.org; daniel@ffwll.ch; Alistair Popple
> <apopple@nvidia.com>
> Subject: [PATCH v3 6/8] mm: Selftests for exclusive device memory
>=20
> Adds some selftests for exclusive device memory.
>=20
> Signed-off-by: Alistair Popple <apopple@nvidia.com>

One minor nit below, but you can add
Tested-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>

> +static int dmirror_exclusive(struct dmirror *dmirror,
> +			     struct hmm_dmirror_cmd *cmd)
> +{
> +	unsigned long start, end, addr;
> +	unsigned long size =3D cmd->npages << PAGE_SHIFT;
> +	struct mm_struct *mm =3D dmirror->notifier.mm;
> +	struct page *pages[64];
> +	struct dmirror_bounce bounce;
> +	unsigned long next;
> +	int ret;
> +
> +	start =3D cmd->addr;
> +	end =3D start + size;
> +	if (end < start)
> +		return -EINVAL;
> +
> +	/* Since the mm is for the mirrored process, get a reference first. */
> +	if (!mmget_not_zero(mm))
> +		return -EINVAL;
> +
> +	mmap_read_lock(mm);
> +	for (addr =3D start; addr < end; addr =3D next) {
> +		int i, mapped;
> +
> +		if (end < addr + (64 << PAGE_SHIFT))
> +			next =3D end;
> +		else
> +			next =3D addr + (64 << PAGE_SHIFT);

I suggest using ARRAY_SIZE(pages) instead of '64' to make the meaning clear=
.