Re: [PATCH 12/36] target: Properly set Sense data length when copy sense

Thinh Nguyen
2022-07-09T00:11:43Z

On 7/7/2022, Dmitry Bogdanov wrote:
> Hi Thinh,
> On Wed, Jul 06, 2022 at 04:35:38PM -0700, Thinh Nguyen wrote:
>> The transport_get_sense_buffer() sets sense data length to be the
>> allocated sense buffer length TRANSPORT_SENSE_BUFFER. However, the sense
>> data length is depending on the sense data description. Check the sense
>> data for cmd->scsi_sense_length.
>>
>> See SPC4-R37 section 4.5.2.1.
>>
>> Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
>> ---
>> drivers/target/target_core_transport.c | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
>> index 9734952a6228..2fc4ba1814c6 100644
>> --- a/drivers/target/target_core_transport.c
>> +++ b/drivers/target/target_core_transport.c
>> @@ -771,8 +771,6 @@ static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
>> if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
>> return NULL;
>>
>> - cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
>> -
>> pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
>> dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
>> return cmd->sense_buffer;
>> @@ -791,7 +789,12 @@ void transport_copy_sense_to_cmd(struct se_cmd *cmd, unsigned char *sense)
>> }
>>
>> cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
>> - memcpy(cmd_sense_buf, sense, cmd->scsi_sense_length);
>> + memcpy(cmd_sense_buf, sense, TRANSPORT_SENSE_BUFFER);
>> +
>> + /* Sense data length = min sense data + additional sense data length */
>> + cmd->scsi_sense_length = min_t(int, 8 + cmd_sense_buf[7],
>> + TRANSPORT_SENSE_BUFFER);
> Looks a bit strange - to copy big amount of data and then to reduce the
> length. Better vice versa - set correct length and copy only that data.

Sure, I'll do that.

Thanks,
Thinh

>> +
>> spin_unlock_irqrestore(&cmd->t_state_lock, flags);
>> }
>> EXPORT_SYMBOL(transport_copy_sense_to_cmd);