Re: [Xen-devel] [PATCH V3 1/3] xen-blkback: add BLKIF_OP_TRIM and backend types

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> On 25.08.11 at 08:34, Li Dongyang <lidongyang@xxxxxxxxxx> wrote:
> On Wed, Aug 24, 2011 at 6:26 PM, Jan Beulich <JBeulich@xxxxxxxxxx> wrote:
>>>>> On 24.08.11 at 11:23, Li Dongyang <lidongyang@xxxxxxxxxx> wrote:
>>> This adds the BLKIF_OP_TRIM for blkfront and blkback, also 2 enums telling
>>> us the type of the backend, used in blkback to determine what to do when we
>>> see a trim request.
>>> The BLKIF_OP_TRIM part is just taken from Owen Smith, Thanks
>>>
>>> Signed-off-by: Owen Smith <owen.smith@xxxxxxxxxx>
>>> Signed-off-by: Li Dongyang <lidongyang@xxxxxxxxxx>
>>> ---
>>>  drivers/block/xen-blkback/common.h |   10 +++++++++-
>>>  include/xen/interface/io/blkif.h   |   19 +++++++++++++++++++
>>>  2 files changed, 28 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/drivers/block/xen-blkback/common.h
>>> b/drivers/block/xen-blkback/common.h
>>> index 9e40b28..146d325 100644
>>> --- a/drivers/block/xen-blkback/common.h
>>> +++ b/drivers/block/xen-blkback/common.h
>>> @@ -113,6 +113,11 @@ enum blkif_protocol {
>>>       BLKIF_PROTOCOL_X86_64 = 3,
>>>  };
>>>
>>> +enum blkif_backend_type {
>>> +     BLKIF_BACKEND_PHY  = 1,
>>> +     BLKIF_BACKEND_FILE = 2,
>>> +};
>>> +
>>>  struct xen_vbd {
>>>       /* What the domain refers to this vbd as. */
>>>       blkif_vdev_t            handle;
>>> @@ -138,6 +143,7 @@ struct xen_blkif {
>>>       unsigned int            irq;
>>>       /* Comms information. */
>>>       enum blkif_protocol     blk_protocol;
>>> +     enum blkif_backend_type blk_backend_type;
>>>       union blkif_back_rings  blk_rings;
>>>       struct vm_struct        *blk_ring_area;
>>>       /* The VBD attached to this interface. */
>>> @@ -159,8 +165,10 @@ struct xen_blkif {
>>>       int                     st_wr_req;
>>>       int                     st_oo_req;
>>>       int                     st_f_req;
>>> +     int                     st_tr_req;
>>>       int                     st_rd_sect;
>>>       int                     st_wr_sect;
>>> +     int                     st_tr_sect;
>>
>> Just to repeat - I don't think this piece of statistic is very useful, the
>> more that you use "int" here while ...
>>
>>>
>>>       wait_queue_head_t       waiting_to_free;
>>>
>>> @@ -182,7 +190,7 @@ struct xen_blkif {
>>>
>>>  struct phys_req {
>>>       unsigned short          dev;
>>> -     unsigned short          nr_sects;
>>> +     blkif_sector_t          nr_sects;
>>
>> ... you specifically widen the field to 64 bits here.
>>
> sounds reasonable, gonna kill the stat stuff

I didn't mean to say kill it all - the st_tr_req is quite reasonable to
have (in line with st_f_req).

Jan


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