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
> Also, all of the changes to this header look somewhat misplaced, they
> should rather be part of the backend patch.
>
> Jan
>
>> struct block_device *bdev;
>> blkif_sector_t sector_number;
>> };
>> diff --git a/include/xen/interface/io/blkif.h
>> b/include/xen/interface/io/blkif.h
>> index 3d5d6db..43762dd 100644
>> --- a/include/xen/interface/io/blkif.h
>> +++ b/include/xen/interface/io/blkif.h
>> @@ -57,6 +57,19 @@ typedef uint64_t blkif_sector_t;
>> * "feature-flush-cache" node!
>> */
>> #define BLKIF_OP_FLUSH_DISKCACHE 3
>> +
>> +/*
>> + * Recognised only if "feature-trim" is present in backend xenbus info.
>> + * The "feature-trim" node contains a boolean indicating whether trim
>> + * requests are likely to succeed or fail. Either way, a trim request
>> + * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
>> + * the underlying block-device hardware. The boolean simply indicates
>> whether
>> + * or not it is worthwhile for the frontend to attempt trim requests.
>> + * If a backend does not recognise BLKIF_OP_TRIM, it should *not*
>> + * create the "feature-trim" node!
>> + */
>> +#define BLKIF_OP_TRIM 5
>> +
>> /*
>> * Maximum scatter/gather segments per request.
>> * This is carefully chosen so that sizeof(struct blkif_ring) <= PAGE_SIZE.
>> @@ -74,6 +87,11 @@ struct blkif_request_rw {
>> } seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
>> };
>>
>> +struct blkif_request_trim {
>> + blkif_sector_t sector_number;
>> + uint64_t nr_sectors;
>> +};
>> +
>> struct blkif_request {
>> uint8_t operation; /* BLKIF_OP_??? */
>> uint8_t nr_segments; /* number of segments */
>> @@ -81,6 +99,7 @@ struct blkif_request {
>> uint64_t id; /* private guest value, echoed in resp */
>> union {
>> struct blkif_request_rw rw;
>> + struct blkif_request_trim trim;
>> } u;
>> };
>>
>
>
>
>
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