2023-09-29 18:10:28

by Bart Van Assche

Subject: Re: [PATCH 19/21] scsi: sd: Add WRITE_ATOMIC_16 support

On 9/29/23 03:27, John Garry wrote:
> +static blk_status_t sd_setup_atomic_cmnd(struct scsi_cmnd *cmd,
> + sector_t lba, unsigned int nr_blocks,
> + unsigned char flags)
> +{
> + cmd->cmd_len = 16;
> + cmd->cmnd[0] = WRITE_ATOMIC_16;
> + cmd->cmnd[1] = flags;
> + put_unaligned_be64(lba, &cmd->cmnd[2]);
> + cmd->cmnd[10] = 0;
> + cmd->cmnd[11] = 0;
> + put_unaligned_be16(nr_blocks, &cmd->cmnd[12]);
> + cmd->cmnd[14] = 0;
> + cmd->cmnd[15] = 0;
> +
> + return BLK_STS_OK;
> +}

Please store the 'dld' value in the GROUP NUMBER field. See e.g.
sd_setup_rw16_cmnd().

> @@ -1139,6 +1156,7 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
> unsigned int nr_blocks = sectors_to_logical(sdp, blk_rq_sectors(rq));
> unsigned int mask = logical_to_sectors(sdp, 1) - 1;
> bool write = rq_data_dir(rq) == WRITE;
> + bool atomic_write = !!(rq->cmd_flags & REQ_ATOMIC) && write;

Please leave out the superfluous "!!".

Thanks,

Bart.

2023-10-02 19:05:58

by John Garry

Subject: Re: [PATCH 19/21] scsi: sd: Add WRITE_ATOMIC_16 support

On 29/09/2023 18:59, Bart Van Assche wrote:
> On 9/29/23 03:27, John Garry wrote:
>> +static blk_status_t sd_setup_atomic_cmnd(struct scsi_cmnd *cmd,
>> +                    sector_t lba, unsigned int nr_blocks,
>> +                    unsigned char flags)
>> +{
>> +    cmd->cmd_len  = 16;
>> +    cmd->cmnd[0]  = WRITE_ATOMIC_16;
>> +    cmd->cmnd[1]  = flags;
>> +    put_unaligned_be64(lba, &cmd->cmnd[2]);
>> +    cmd->cmnd[10] = 0;
>> +    cmd->cmnd[11] = 0;
>> +    put_unaligned_be16(nr_blocks, &cmd->cmnd[12]);
>> +    cmd->cmnd[14] = 0;
>> +    cmd->cmnd[15] = 0;
>> +
>> +    return BLK_STS_OK;
>> +}
>
> Please store the 'dld' value in the GROUP NUMBER field. See e.g.
> sd_setup_rw16_cmnd().

Are you sure that WRITE ATOMIC (16) supports dld?

>
>> @@ -1139,6 +1156,7 @@ static blk_status_t
>> sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
>>       unsigned int nr_blocks = sectors_to_logical(sdp,
>> blk_rq_sectors(rq));
>>       unsigned int mask = logical_to_sectors(sdp, 1) - 1;
>>       bool write = rq_data_dir(rq) == WRITE;
>> +    bool atomic_write = !!(rq->cmd_flags & REQ_ATOMIC) && write;
>
> Please leave out the superfluous "!!".

ok, fine.

Thanks,
John

2023-10-02 21:24:30

by Bart Van Assche

Subject: Re: [PATCH 19/21] scsi: sd: Add WRITE_ATOMIC_16 support

On 10/2/23 04:36, John Garry wrote:
> On 29/09/2023 18:59, Bart Van Assche wrote:
>> On 9/29/23 03:27, John Garry wrote:
>>> +static blk_status_t sd_setup_atomic_cmnd(struct scsi_cmnd *cmd,
>>> +                    sector_t lba, unsigned int nr_blocks,
>>> +                    unsigned char flags)
>>> +{
>>> +    cmd->cmd_len  = 16;
>>> +    cmd->cmnd[0]  = WRITE_ATOMIC_16;
>>> +    cmd->cmnd[1]  = flags;
>>> +    put_unaligned_be64(lba, &cmd->cmnd[2]);
>>> +    cmd->cmnd[10] = 0;
>>> +    cmd->cmnd[11] = 0;
>>> +    put_unaligned_be16(nr_blocks, &cmd->cmnd[12]);
>>> +    cmd->cmnd[14] = 0;
>>> +    cmd->cmnd[15] = 0;
>>> +
>>> +    return BLK_STS_OK;
>>> +}
>>
>> Please store the 'dld' value in the GROUP NUMBER field. See e.g.
>> sd_setup_rw16_cmnd().
>
> Are you sure that WRITE ATOMIC (16) supports dld?

Hi John,

I was assuming that DLD would be supported by the WRITE ATOMIC(16)
command. After having taken another look at the latest SBC-5 draft
I see that the DLD2/DLD1/DLD0 bits are not present in the WRITE
ATOMIC(16) command. So please ignore my comment above.

Thanks,

Bart.