linux-kernel - Re: [PATCH v1 31/36] vfio/pci: drop nth

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Message-ID: <20250828125251.08e4a429.alex.williamson@redhat.com>
Date: Thu, 28 Aug 2025 12:52:51 -0600
From: Alex Williamson <alex.williamson@...hat.com>
To: David Hildenbrand <david@...hat.com>
Cc: linux-kernel@...r.kernel.org, Brett Creeley <brett.creeley@....com>,
 Jason Gunthorpe <jgg@...pe.ca>, Yishai Hadas <yishaih@...dia.com>, Shameer
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Subject: Re: [PATCH v1 31/36] vfio/pci: drop nth_page() usage within SG
 entry

On Thu, 28 Aug 2025 00:01:35 +0200
David Hildenbrand <david@...hat.com> wrote:

> It's no longer required to use nth_page() when iterating pages within a
> single SG entry, so let's drop the nth_page() usage.
> 
> Cc: Brett Creeley <brett.creeley@....com>
> Cc: Jason Gunthorpe <jgg@...pe.ca>
> Cc: Yishai Hadas <yishaih@...dia.com>
> Cc: Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
> Cc: Kevin Tian <kevin.tian@...el.com>
> Cc: Alex Williamson <alex.williamson@...hat.com>
> Signed-off-by: David Hildenbrand <david@...hat.com>
> ---
>  drivers/vfio/pci/pds/lm.c         | 3 +--
>  drivers/vfio/pci/virtio/migrate.c | 3 +--
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/vfio/pci/pds/lm.c b/drivers/vfio/pci/pds/lm.c
> index f2673d395236a..4d70c833fa32e 100644
> --- a/drivers/vfio/pci/pds/lm.c
> +++ b/drivers/vfio/pci/pds/lm.c
> @@ -151,8 +151,7 @@ static struct page *pds_vfio_get_file_page(struct pds_vfio_lm_file *lm_file,
>  			lm_file->last_offset_sg = sg;
>  			lm_file->sg_last_entry += i;
>  			lm_file->last_offset = cur_offset;
> -			return nth_page(sg_page(sg),
> -					(offset - cur_offset) / PAGE_SIZE);
> +			return sg_page(sg) + (offset - cur_offset) / PAGE_SIZE;
>  		}
>  		cur_offset += sg->length;
>  	}
> diff --git a/drivers/vfio/pci/virtio/migrate.c b/drivers/vfio/pci/virtio/migrate.c
> index ba92bb4e9af94..7dd0ac866461d 100644
> --- a/drivers/vfio/pci/virtio/migrate.c
> +++ b/drivers/vfio/pci/virtio/migrate.c
> @@ -53,8 +53,7 @@ virtiovf_get_migration_page(struct virtiovf_data_buffer *buf,
>  			buf->last_offset_sg = sg;
>  			buf->sg_last_entry += i;
>  			buf->last_offset = cur_offset;
> -			return nth_page(sg_page(sg),
> -					(offset - cur_offset) / PAGE_SIZE);
> +			return sg_page(sg) + (offset - cur_offset) / PAGE_SIZE;
>  		}
>  		cur_offset += sg->length;
>  	}

Reviewed-by: Alex Williamson <alex.williamson@...hat.com>