You are absolutely right.
That works too and makes the patch a lot simpler/better.
I will resend the patch with your suggestion.
Thanks!
On Sun, Mar 24, 2013 at 5:33 AM, Alexander Nezhinsky
<nezhinsky@xxxxxxxxx> wrote:
> sorry for resending, sent HTML for the first time...
>
> On Sat, Mar 23, 2013 at 11:16 PM, Ronnie Sahlberg
> <ronniesahlberg@xxxxxxxxx> wrote:
>>
>> This patch adds support to return overflow/underflow residuals
>> for the cases where the transport layer (iSCSI, ...) specifies
>> an EDTL that is not matching the SCSI transdfer length.
>>
>> Additionally, in case of residual underflow it will also clamp the size of
>> returned DATA-IN to the amount of data that was actually read and not the
>> EDTL that was requested.
>>
>
>>
>> diff --git a/usr/sbc.c b/usr/sbc.c
>>
>> index 48dab04..26cceb1 100644
>> --- a/usr/sbc.c
>> +++ b/usr/sbc.c
>> @@ -226,6 +226,8 @@ static int sbc_rw(int host_no, struct scsi_cmd *cmd)
>> int ret;
>> uint64_t lba;
>> uint32_t tl;
>> + long residual = 0;
>> + long length;
>> unsigned char key = ILLEGAL_REQUEST;
>> uint16_t asc = ASC_LUN_NOT_SUPPORTED;
>> struct scsi_lu *lu = cmd->dev;
>> @@ -335,12 +337,36 @@ static int sbc_rw(int host_no, struct scsi_cmd *cmd)
>> cmd->offset = lba << cmd->dev->blk_shift;
>> cmd->tl = tl << cmd->dev->blk_shift;
>>
>> + /* Handle residuals */
>> + switch (cmd->scb[0]) {
>> + case READ_6:
>> + case READ_10:
>> + case READ_12:
>> + case READ_16:
>> + length = scsi_get_in_length(cmd);
>> + if (length != cmd->tl) {
>> + residual = length - cmd->tl;
>> +
>> + if (length > cmd->tl) {
>> + length = cmd->tl;
>> + scsi_set_in_transfer_len(cmd, cmd->tl);
>> + scsi_set_in_length(cmd, cmd->tl);
>> + }
>> + }
>> + break;
>> + }
>> +
>> ret = cmd->dev->bst->bs_cmd_submit(cmd);
>> if (ret) {
>> key = HARDWARE_ERROR;
>> asc = ASC_INTERNAL_TGT_FAILURE;
>> - } else
>> - return SAM_STAT_GOOD;
>> + goto sense;
>> + }
>> +
>> + if (residual)
>> + scsi_set_in_resid(cmd, residual);
>> +
>> + return SAM_STAT_GOOD;
>>
>> sense:
>> cmd->offset = 0;
>> --
>> 1.7.3.1
>>
>
> I think that scsi_set_in_resid_by_actual() already does all the work,
> doesn't it?
> If i don't miss any details the following patch is enough:
>
> diff --git a/usr/sbc.c b/usr/sbc.c
> index 48dab04..f3248a1 100644
> --- a/usr/sbc.c
> +++ b/usr/sbc.c
> @@ -230,6 +230,17 @@ static int sbc_rw(int host_no, struct scsi_cmd *cmd)
>
> uint16_t asc = ASC_LUN_NOT_SUPPORTED;
> struct scsi_lu *lu = cmd->dev;
>
> + switch (cmd->scb[0]) {
> + case READ_6:
> + case READ_10:
> + case READ_12:
> + case READ_16:
> + if (cmd->tl != scsi_get_in_length(cmd))
> + scsi_set_in_resid_by_actual(cmd, cmd->tl);
> + default:
> + break;
> + }
> +
> ret = device_reserved(cmd);
> if (ret)
> return SAM_STAT_RESERVATION_CONFLICT;
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