Subject: Re: [[Xen-devel] [PATCH net-next v3] xen-netfront: clean up code in xennet_release_rx_bufs

From: David Vrabel <[email-masked]>
Date: Thu, 23 Jan 2014 10:55:36 +0000

On 23/01/14 01:36, Annie Li wrote:
> From: Annie Li <[email-masked]>
> 
> This patch removes grant transfer code from netfront, and improves ending
> grant acess mechanism since gnttab_end_foreign_access_ref may fail when
> the grant entry is currently used for reading or writing.
> 
> * release grant reference and skb for tx/rx path, use get_page/put_page to
> ensure page is released when grant access is completed successfully.
> * change corresponding code in xen-blkfront/xen-tpmfront/xen-pcifront because
> of code change for put_page in gnttab_end_foreign_access.
> * clean up grant transfer code kept from old netfront(2.6.18) which grants
> pages for access/map and transfer. But grant transfer is deprecated in current
> netfront, so remove corresponding release code for transfer.
> 
> V3: Changes as suggestion from David Vrabel, ensure pages are not freed untill
> grant acess is ended.
> 
> V2: improve patch comments.
> Signed-off-by: Annie Li <[email-masked]>
> ---
>  drivers/block/xen-blkfront.c    |   25 ++++++++---
>  drivers/char/tpm/xen-tpmfront.c |    7 +++-
>  drivers/net/xen-netfront.c      |   93 ++++++++++++--------------------------
>  drivers/pci/xen-pcifront.c      |    7 +++-
>  drivers/xen/grant-table.c       |    4 +-
>  5 files changed, 63 insertions(+), 73 deletions(-)

I don't understand why you've made all these unnecessary changes to the
other frontends and grant-table.c.

The xen-netfront.c changes are fine on their own.

David