Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Received-SPF: None (esa6.hc3370-68.iphmx.com: no sender
  authenticity information available from domain of
  roger.pau@citrix.com) identity=pra; client-ip=162.221.158.21;
  receiver=esa6.hc3370-68.iphmx.com;
  envelope-from="roger.pau@citrix.com";
  x-sender="roger.pau@citrix.com";
  x-conformance=sidf_compatible
Received-SPF: Pass (esa6.hc3370-68.iphmx.com: domain of
  roger.pau@citrix.com designates 162.221.158.21 as permitted
  sender) identity=mailfrom; client-ip=162.221.158.21;
  receiver=esa6.hc3370-68.iphmx.com;
  envelope-from="roger.pau@citrix.com";
  x-sender="roger.pau@citrix.com";
  x-conformance=sidf_compatible; x-record-type="v=spf1";
  x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133
  ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4
  ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88
  ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83
  ip4:168.245.78.127 ~all"
Received-SPF: None (esa6.hc3370-68.iphmx.com: no sender
  authenticity information available from domain of
  postmaster@mail.citrix.com) identity=helo;
  client-ip=162.221.158.21; receiver=esa6.hc3370-68.iphmx.com;
  envelope-from="roger.pau@citrix.com";
  x-sender="postmaster@mail.citrix.com";
  x-conformance=sidf_compatible
IronPort-SDR: iR1cwtc6wIxZHy2095D3SobXiBpJi1pHjnR4cTvwIX4HwAo3C1DNnED/QdKE4qoxNmS2nAl6jV
 dbJIfWoZdXEkP183BBYzQ6TbB8GAIJFJsQHT5i05dmAWRfPp9TMq78jYy6zAhB5tY8PZ+Q7C35
 eA/Mk5kAW7Vl1HUChfFa3m08+pqPatmh5F6H00J2FJ3RrXlA6MT4yoduIrrON+HcCXhgi/Wx1X
 VozdPrV+m5W8VHG95mKIH53r6u455YK/zwGOBAEcLqVjoFxNkKJ+9EpJ1DfbZb+f6uwBMlnkjs
 NjI=
Date:   Thu, 5 Mar 2020 13:42:55 +0100
From:   Roger Pau =?utf-8?B?TW9ubsOp?= <roger.pau@citrix.com>
To:     Juergen Gross <jgross@suse.com>
CC:     <xen-devel@lists.xenproject.org>, <linux-block@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH v2] xen/blkfront: fix ring info addressing
Message-ID: <20200305124255.GW24458@Air-de-Roger.citrite.net>
References: <20200305114044.20235-1-jgross@suse.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20200305114044.20235-1-jgross@suse.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Mar 05, 2020 at 12:40:44PM +0100, Juergen Gross wrote:
> Commit 0265d6e8ddb890 ("xen/blkfront: limit allocated memory size to
> actual use case") made struct blkfront_ring_info size dynamic. This is
> fine when running with only one queue, but with multiple queues the
> addressing of the single queues has to be adapted as the structs are
> allocated in an array.
> 
> Fixes: 0265d6e8ddb890 ("xen/blkfront: limit allocated memory size to actual use case")
> Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
> V2:
> - get rid of rinfo_ptr() helper
> - use proper parenthesis in for_each_rinfo()
> - rename rinfo parameter of for_each_rinfo()
> ---
>  drivers/block/xen-blkfront.c | 79 +++++++++++++++++++++++---------------------
>  1 file changed, 42 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index e2ad6bba2281..8e844da826db 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -213,6 +213,7 @@ struct blkfront_info
>  	struct blk_mq_tag_set tag_set;
>  	struct blkfront_ring_info *rinfo;
>  	unsigned int nr_rings;
> +	unsigned int rinfo_size;
>  	/* Save uncomplete reqs and bios for migration. */
>  	struct list_head requests;
>  	struct bio_list bio_list;
> @@ -259,6 +260,18 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo);
>  static void blkfront_gather_backend_features(struct blkfront_info *info);
>  static int negotiate_mq(struct blkfront_info *info);
>  
> +#define for_each_rinfo(info, ptr, idx)				\
> +	for ((ptr) = (info)->rinfo, (idx) = 0;			\
> +	     (idx) < (info)->nr_rings;				\
> +	     (idx)++, (ptr) = (void *)(ptr) + (info)->rinfo_size)
> +
> +static struct blkfront_ring_info *get_rinfo(struct blkfront_info *info,

I still think inline should be added here, but I don't have such a
strong opinion to block the patch on it.

Also, info should be constified AFAICT.

With at least info constified:

Acked-by: Roger Pau Monné <roger.pau@citrix.com>

Can you queue this through the Xen tree?

Thanks, Roger.