Re: [PATCH 5/9] target: Skip ->queue_data_in() callbacks forCOMPARE_AND_WRITE

From: Nicholas A. Bellinger
Date: Wed Aug 21 2013 - 03:14:01 EST


On Tue, 2013-08-20 at 23:32 -0700, Christoph Hellwig wrote:
> > @@ -1832,7 +1832,8 @@ static void transport_complete_qf(struct se_cmd *cmd)
> > ret = cmd->se_tfo->queue_data_in(cmd);
> > break;
> > case DMA_TO_DEVICE:
> > - if (cmd->t_bidi_data_sg) {
> > + if (cmd->t_bidi_data_sg &&
> > + cmd->t_task_cdb[0] != COMPARE_AND_WRITE) {
>
> This is not the place to hardcode specific cdb opcodes. Should be
> a flag with a defined meaning on the command.
>

Since this code path is only ever reached after a successful comparison
+ submission of the subsequent write payload, this is fine to change to
use SCF_COMPARE_AND_WRITE_POST flag..

Folding in the following patch.

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 60d1336..70a6adb 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1833,7 +1833,7 @@ static void transport_complete_qf(struct se_cmd *cmd)
break;
case DMA_TO_DEVICE:
if (cmd->t_bidi_data_sg &&
- cmd->t_task_cdb[0] != COMPARE_AND_WRITE) {
+ !(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE_POST)) {
ret = cmd->se_tfo->queue_data_in(cmd);
if (ret < 0)
break;
@@ -1949,7 +1949,7 @@ static void target_complete_ok_work(struct work_struct *work)
* Check if we need to send READ payload for BIDI-COMMAND
*/
if (cmd->t_bidi_data_sg &&
- cmd->t_task_cdb[0] != COMPARE_AND_WRITE) {
+ !(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE_POST)) {
spin_lock(&cmd->se_lun->lun_sep_lock);
if (cmd->se_lun->lun_sep) {
cmd->se_lun->lun_sep->sep_stats.tx_data_octets +=


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