Re: [Xen-devel] [PATCH v3] xen-blk(front|back): Handle large physical sector disks

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 22.05.13 at 15:15, Stefan Bader <stefan.bader@xxxxxxxxxxxxx> wrote:
> On 22.05.2013 14:21, Jan Beulich wrote:
>> 
>> The only thing I haven't seen so far is a patch to the master
>> copy of blkif.h to document the new xenstore node.
>> 
> 
> Ok, maybe something like this. What I realize is that I deliberately used
> unsigned int as this is defined as 32bit on x86. But maybe it should be 
> changed
> to uint32_t?

I don't think this matters much, as the values are represented as
strings anyway. Personally I'm not even sure that specifying a
type here is really necessary. Let's see what others think.

Jan

> From 8d1023ce11b9067346e9794d95b2876d98484f43 Mon Sep 17 00:00:00 2001
> From: Stefan Bader <stefan.bader@xxxxxxxxxxxxx>
> Date: Wed, 22 May 2013 15:11:18 +0200
> Subject: [PATCH] blkif.h: Document the physical-sector-size extension
> 
> Signed-off-by: Stefan Bader <stefan.bader@xxxxxxxxxxxxx>
> ---
>  xen/include/public/io/blkif.h |   14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/include/public/io/blkif.h b/xen/include/public/io/blkif.h
> index 97b423b..f7c3366 100644
> --- a/xen/include/public/io/blkif.h
> +++ b/xen/include/public/io/blkif.h
> @@ -208,12 +208,17 @@
>   * sector-size
>   *      Values:         <uint32_t>
>   *
> - *      The native sector size, in bytes, of the backend device.
> + *      The logical sector size, in bytes, of the backend device.
> + *
> + * physical-sector-size
> + *      Values:         <unsigned int>
> + *
> + *      The physical sector size, in bytes, of the backend device.
>   *
>   * sectors
>   *      Values:         <uint64_t>
>   *
> - *      The size of the backend device, expressed in units of its native
> + *      The size of the backend device, expressed in units of its logical
>   *      sector size ("sector-size").
>   *
>   
> *****************************************************************************
> @@ -473,8 +478,9 @@
>   * NB. first_sect and last_sect in blkif_request_segment, as well as
>   * sector_number in blkif_request, are always expressed in 512-byte units.
>   * However they must be properly aligned to the real sector size of the
> - * physical disk, which is reported in the "sector-size" node in the backend
> - * xenbus info. Also the xenbus "sectors" node is expressed in 512-byte 
> units.
> + * physical disk, which is reported in the "physical-sector-size" node in
> + * the backend xenbus info. Also the xenbus "sectors" node is expressed in
> + * 512-byte units.
>   */
>  struct blkif_request_segment {
>      grant_ref_t gref;        /* reference to I/O buffer frame        */
> -- 
> 1.7.9.5




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