Re: [PATCH v3 5/5] target/file: enable WRITE SAME when protection info is enabled

Akinobu Mita
2015-04-27T13:02:07Z

2015-04-26 18:58 GMT+09:00 Sagi Grimberg <sagig@dev.mellanox.co.il>:
> On 4/25/2015 5:33 PM, Akinobu Mita wrote:
>>
>> Now we can generate correct PI for WRITE SAME command, so it is
>> unnecessary to disallow WRITE SAME when protection info is enabled.
>>
>> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
>> Cc: Nicholas Bellinger <nab@linux-iscsi.org>
>> Cc: Sagi Grimberg <sagig@mellanox.com>
>> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
>> Cc: Christoph Hellwig <hch@lst.de>
>> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
>> Cc: target-devel@vger.kernel.org
>> Cc: linux-scsi@vger.kernel.org
>> ---
>> * No change from v2
>>
>> drivers/target/target_core_file.c | 18 +++++++++++++-----
>> 1 file changed, 13 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/target/target_core_file.c
>> b/drivers/target/target_core_file.c
>> index 829817a..fe98f58 100644
>> --- a/drivers/target/target_core_file.c
>> +++ b/drivers/target/target_core_file.c
>> @@ -376,16 +376,12 @@ fd_execute_write_same(struct se_cmd *cmd)
>> struct bio_vec *bvec;
>> unsigned int len = 0, i;
>> ssize_t ret;
>> + sense_reason_t rc;
>>
>> if (!nolb) {
>> target_complete_cmd(cmd, SAM_STAT_GOOD);
>> return 0;
>> }
>> - if (cmd->prot_op) {
>> - pr_err("WRITE_SAME: Protection information with FILEIO"
>> - " backends not supported\n");
>> - return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
>> - }
>>
>> if (cmd->t_data_nents > 1 ||
>> cmd->t_data_sg[0].length !=
>> cmd->se_dev->dev_attrib.block_size) {
>> @@ -397,6 +393,10 @@ fd_execute_write_same(struct se_cmd *cmd)
>> return TCM_INVALID_CDB_FIELD;
>> }
>>
>> + rc = sbc_dif_verify(cmd, cmd->t_task_lba, nolb, 0, cmd->t_prot_sg,
>> 0);
>> + if (rc)
>> + return rc;
>> +
>> bvec = kcalloc(nolb, sizeof(struct bio_vec), GFP_KERNEL);
>> if (!bvec)
>> return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
>> @@ -418,6 +418,14 @@ fd_execute_write_same(struct se_cmd *cmd)
>> return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
>> }
>>
>> + if (cmd->prot_op) {
>> + ret = fd_do_rw(cmd, fd_dev->fd_prot_file,
>> se_dev->prot_length,
>> + cmd->t_prot_sg, cmd->t_prot_nents,
>> + cmd->prot_length, 1);
>> + if (ret < 0)
>> + return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
>> + }
>> +
>> target_complete_cmd(cmd, SAM_STAT_GOOD);
>> return 0;
>> }
>>
>
> This looks good,

As you pointed out in the other mail, this change doesn't work with
a real HW fabric because it doesn't generate multiple same protection
fields for a single data block currently.

So I'm considering dropping this from this patch series for now.

> iblock is needed too though. I think you just need a missing call to
> iblock_alloc_bip() and you're good to go (you can use scsi_debug with
> dif/dix to test it). I think it belongs in the same patch.

Thanks for the information. I'll take a look.