[PATCH] libata irq-pio: cleanup ata_qc_issue_prot()

ata_qc_issue_prot():
    - cleanup and let the PIO data out case always go through the
ata_dataout_task() codepath.
      (Previously for PIO data out case, 2 code pathes were used
        - irq case goes through ata_data_out_task() codepath.
        - polling case jumps over the HSM_ST_FIRST state and goes to
HSM_ST and ata_pio_task() directly.)

  ata_dataout_task():
    - rearrange the queue_work() code to handle the PIO data out +
polling case.

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index cf5a138..02a7a9e 100644 (file)
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -3407,24 +3407,24 @@ int ata_qc_issue_prot(struct ata_queued_cmd *qc)
 
                ata_tf_to_host_nolock(ap, &qc->tf);
 
-               if (qc->tf.flags & ATA_TFLAG_POLLING) {
-                       /* polling PIO */
-                       ap->hsm_task_state = HSM_ST;
-                       queue_work(ata_wq, &ap->pio_task);
+               if (qc->tf.flags & ATA_TFLAG_WRITE) {
+                       /* PIO data out protocol */
+                       ap->hsm_task_state = HSM_ST_FIRST;
+                       queue_work(ata_wq, &ap->dataout_task);
+
+                       /* always send first data block using
+                        * the ata_dataout_task() codepath.
+                        */
                } else {
-                       /* interrupt driven PIO */
-                       if (qc->tf.flags & ATA_TFLAG_WRITE) {
-                               /* PIO data out protocol */
-                               ap->hsm_task_state = HSM_ST_FIRST;
-                               queue_work(ata_wq, &ap->dataout_task);
-
-                               /* send first data block by polling */
-                       } else {
-                               /* PIO data in protocol */
-                               ap->hsm_task_state = HSM_ST;
-
-                               /* interrupt handler takes over from here */
-                       }
+                       /* PIO data in protocol */
+                       ap->hsm_task_state = HSM_ST;
+
+                       if (qc->tf.flags & ATA_TFLAG_POLLING)
+                               queue_work(ata_wq, &ap->pio_task);
+
+                       /* if polling, ata_pio_task() handles the rest.
+                        * otherwise, interrupt handler takes over from here.
+                        */
                }
 
                break;
@@ -4005,15 +4005,15 @@ static void ata_dataout_task(void *_data)
                ap->hsm_task_state = HSM_ST;
                ata_pio_sector(qc);
                ata_altstatus(ap); /* flush */
-
-               /* interrupt handler takes over from here */
-       } else {
+       } else
                /* send CDB */
                atapi_send_cdb(ap, qc);
 
-               if (qc->tf.flags & ATA_TFLAG_POLLING)
-                       queue_work(ata_wq, &ap->pio_task);
-       }
+       /* if polling, ata_pio_task() handles the rest.
+        * otherwise, interrupt handler takes over from here.
+        */
+       if (qc->tf.flags & ATA_TFLAG_POLLING)
+               queue_work(ata_wq, &ap->pio_task);
 
        spin_unlock_irqrestore(&ap->host_set->lock, flags);