patch 6/8:
 - Delegate irq driven pio to workqueue.
 - HSM_ST_LAST is kept in the interrupt since this is not CPU intensive.
   (Mostly for DMA and non-data.)

Signed-off-by: Albert Lee <[EMAIL PROTECTED]>
Cc: Alan Cox <[EMAIL PROTECTED]>
Cc: Tejun Heo <[EMAIL PROTECTED]>
---
sata_sil is not changed to delegate to workqueue at this moment.
Maybe we can add such feature in the future if needed.


diff -Nrup 05_polling_ack/drivers/ata/libata-core.c 
06_irq_wq/drivers/ata/libata-core.c
--- 05_polling_ack/drivers/ata/libata-core.c    2007-05-16 13:53:20.000000000 
+0800
+++ 06_irq_wq/drivers/ata/libata-core.c 2007-05-16 13:53:25.000000000 +0800
@@ -4864,20 +4864,15 @@ err_out:
 
 static inline int ata_hsm_ok_in_wq(struct ata_port *ap, struct ata_queued_cmd 
*qc)
 {
-       if (qc->tf.flags & ATA_TFLAG_POLLING)
-               return 1;
-
-       if (ap->hsm_task_state == HSM_ST_FIRST) {
-               if (qc->tf.protocol == ATA_PROT_PIO &&
-                   (qc->tf.flags & ATA_TFLAG_WRITE))
-                   return 1;
-
-               if (is_atapi_taskfile(&qc->tf) &&
-                   !(qc->dev->flags & ATA_DFLAG_CDB_INTR))
-                       return 1;
+       switch (qc->tf.protocol) {
+       case ATA_PROT_DMA:
+               return 0;
+       case ATA_PROT_ATAPI_DMA:
+               if (ap->hsm_task_state != HSM_ST_FIRST)
+                       return 0;
        }
 
-       return 0;
+       return (ap->pflags & ATA_PFLAG_HSM_WQ) ? 1 : 0;
 }
 
 /**
@@ -5217,6 +5212,39 @@ fsm_start:
 }
 
 /**
+ *     ata_irq_task - queue task for irq pio
+ *     @work: associated work_struct
+ *
+ *     LOCKING:
+ *     None.
+ */
+
+static void ata_irq_task(struct work_struct *work)
+{
+       struct ata_port *ap =
+               container_of(work, struct ata_port, port_task.work);
+       struct ata_queued_cmd *qc = ap->port_task_data;
+       u8 status;
+
+       WARN_ON(ap->hsm_task_state == HSM_ST_IDLE);
+
+       /* double check the device is not busy */
+       status = ata_chk_status(ap);
+       if (status & ATA_BUSY) {
+               ata_port_printk(ap, KERN_ERR, "Unexpected device busy "
+                               "(Status 0x%x)\n", status);
+               return;
+       }
+
+       /* move the HSM */
+       ata_hsm_move(ap, qc, status, 1);
+
+       /* another command or interrupt handler
+        * may be running at this point.
+        */
+}
+
+/**
  *     ata_qc_new - Request an available ATA command, for queueing
  *     @ap: Port associated with device @dev
  *     @dev: Device from whom we request an available command structure
@@ -5756,11 +5784,21 @@ inline unsigned int ata_host_intr (struc
        /* ack bmdma irq events */
        ap->ops->irq_clear(ap);
 
-       ata_hsm_move(ap, qc, status, 0);
+       /* move the HSM */
+       switch (ap->hsm_task_state) {
+       case HSM_ST_FIRST:
+       case HSM_ST:
+               /* delegate PIO data transfer to workqueue */
+               ap->pflags |= ATA_PFLAG_HSM_WQ;
+               ata_port_queue_task(ap, ata_irq_task, qc, 0);
+               break;
+       default:
+               ata_hsm_move(ap, qc, status, 0);
 
-       if (unlikely(qc->err_mask) && (qc->tf.protocol == ATA_PROT_DMA ||
-                                      qc->tf.protocol == ATA_PROT_ATAPI_DMA))
-               ata_ehi_push_desc(ehi, "BMDMA stat 0x%x", host_stat);
+               if (unlikely(qc->err_mask) && (qc->tf.protocol == ATA_PROT_DMA 
||
+                                              qc->tf.protocol == 
ATA_PROT_ATAPI_DMA))
+                       ata_ehi_push_desc(ehi, "BMDMA stat 0x%x", host_stat);
+       }
 
        return 1;       /* irq handled */
 


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