[PATCH] libata: pass qc around intead of ap during PIO
The current code passes pointer to ap around and repeatedly performs
ata_qc_from_tag() to access the ongoing qc. This is unnatural and
makes EH synchronization cumbersome. Make PIO codes deal with qc
instead of ap.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 007d188..e9002a4 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -3416,7 +3416,7 @@
/**
* ata_pio_poll - poll using PIO, depending on current state
- * @ap: the target ata_port
+ * @qc: qc in progress
*
* LOCKING:
* None. (executing in kernel thread context)
@@ -3424,17 +3424,13 @@
* RETURNS:
* timeout value to use
*/
-
-static unsigned long ata_pio_poll(struct ata_port *ap)
+static unsigned long ata_pio_poll(struct ata_queued_cmd *qc)
{
- struct ata_queued_cmd *qc;
+ struct ata_port *ap = qc->ap;
u8 status;
unsigned int poll_state = HSM_ST_UNKNOWN;
unsigned int reg_state = HSM_ST_UNKNOWN;
- qc = ata_qc_from_tag(ap, ap->active_tag);
- WARN_ON(qc == NULL);
-
switch (ap->hsm_task_state) {
case HSM_ST:
case HSM_ST_POLL:
@@ -3468,7 +3464,7 @@
/**
* ata_pio_complete - check if drive is busy or idle
- * @ap: the target ata_port
+ * @qc: qc to complete
*
* LOCKING:
* None. (executing in kernel thread context)
@@ -3476,10 +3472,9 @@
* RETURNS:
* Non-zero if qc completed, zero otherwise.
*/
-
-static int ata_pio_complete (struct ata_port *ap)
+static int ata_pio_complete(struct ata_queued_cmd *qc)
{
- struct ata_queued_cmd *qc;
+ struct ata_port *ap = qc->ap;
u8 drv_stat;
/*
@@ -3500,9 +3495,6 @@
}
}
- qc = ata_qc_from_tag(ap, ap->active_tag);
- WARN_ON(qc == NULL);
-
drv_stat = ata_wait_idle(ap);
if (!ata_ok(drv_stat)) {
qc->err_mask |= __ac_err_mask(drv_stat);
@@ -3838,15 +3830,14 @@
/**
* ata_pio_block - start PIO on a block
- * @ap: the target ata_port
+ * @qc: qc to transfer block for
*
* LOCKING:
* None. (executing in kernel thread context)
*/
-
-static void ata_pio_block(struct ata_port *ap)
+static void ata_pio_block(struct ata_queued_cmd *qc)
{
- struct ata_queued_cmd *qc;
+ struct ata_port *ap = qc->ap;
u8 status;
/*
@@ -3868,9 +3859,6 @@
}
}
- qc = ata_qc_from_tag(ap, ap->active_tag);
- WARN_ON(qc == NULL);
-
/* check error */
if (status & (ATA_ERR | ATA_DF)) {
qc->err_mask |= AC_ERR_DEV;
@@ -3899,12 +3887,9 @@
}
}
-static void ata_pio_error(struct ata_port *ap)
+static void ata_pio_error(struct ata_queued_cmd *qc)
{
- struct ata_queued_cmd *qc;
-
- qc = ata_qc_from_tag(ap, ap->active_tag);
- WARN_ON(qc == NULL);
+ struct ata_port *ap = qc->ap;
if (qc->tf.command != ATA_CMD_PACKET)
printk(KERN_WARNING "ata%u: dev %u PIO error\n",
@@ -3922,7 +3907,8 @@
static void ata_pio_task(void *_data)
{
- struct ata_port *ap = _data;
+ struct ata_queued_cmd *qc = _data;
+ struct ata_port *ap = qc->ap;
unsigned long timeout;
int qc_completed;
@@ -3935,33 +3921,33 @@
return;
case HSM_ST:
- ata_pio_block(ap);
+ ata_pio_block(qc);
break;
case HSM_ST_LAST:
- qc_completed = ata_pio_complete(ap);
+ qc_completed = ata_pio_complete(qc);
break;
case HSM_ST_POLL:
case HSM_ST_LAST_POLL:
- timeout = ata_pio_poll(ap);
+ timeout = ata_pio_poll(qc);
break;
case HSM_ST_TMOUT:
case HSM_ST_ERR:
- ata_pio_error(ap);
+ ata_pio_error(qc);
return;
}
if (timeout)
- ata_port_queue_task(ap, ata_pio_task, ap, timeout);
+ ata_port_queue_task(ap, ata_pio_task, qc, timeout);
else if (!qc_completed)
goto fsm_start;
}
/**
* atapi_packet_task - Write CDB bytes to hardware
- * @_data: Port to which ATAPI device is attached.
+ * @_data: qc in progress
*
* When device has indicated its readiness to accept
* a CDB, this function is called. Send the CDB.
@@ -3972,17 +3958,12 @@
* LOCKING:
* Kernel thread context (may sleep)
*/
-
static void atapi_packet_task(void *_data)
{
- struct ata_port *ap = _data;
- struct ata_queued_cmd *qc;
+ struct ata_queued_cmd *qc = _data;
+ struct ata_port *ap = qc->ap;
u8 status;
- qc = ata_qc_from_tag(ap, ap->active_tag);
- WARN_ON(qc == NULL);
- WARN_ON(!(qc->flags & ATA_QCFLAG_ACTIVE));
-
/* sleep-wait for BSY to clear */
DPRINTK("busy wait\n");
if (ata_busy_sleep(ap, ATA_TMOUT_CDB_QUICK, ATA_TMOUT_CDB)) {
@@ -4022,7 +4003,7 @@
/* PIO commands are handled by polling */
ap->hsm_task_state = HSM_ST;
- ata_port_queue_task(ap, ata_pio_task, ap, 0);
+ ata_port_queue_task(ap, ata_pio_task, qc, 0);
}
return;
@@ -4328,26 +4309,26 @@
ata_qc_set_polling(qc);
ata_tf_to_host(ap, &qc->tf);
ap->hsm_task_state = HSM_ST;
- ata_port_queue_task(ap, ata_pio_task, ap, 0);
+ ata_port_queue_task(ap, ata_pio_task, qc, 0);
break;
case ATA_PROT_ATAPI:
ata_qc_set_polling(qc);
ata_tf_to_host(ap, &qc->tf);
- ata_port_queue_task(ap, atapi_packet_task, ap, 0);
+ ata_port_queue_task(ap, atapi_packet_task, qc, 0);
break;
case ATA_PROT_ATAPI_NODATA:
ap->flags |= ATA_FLAG_NOINTR;
ata_tf_to_host(ap, &qc->tf);
- ata_port_queue_task(ap, atapi_packet_task, ap, 0);
+ ata_port_queue_task(ap, atapi_packet_task, qc, 0);
break;
case ATA_PROT_ATAPI_DMA:
ap->flags |= ATA_FLAG_NOINTR;
ap->ops->tf_load(ap, &qc->tf); /* load tf registers */
ap->ops->bmdma_setup(qc); /* set up bmdma */
- ata_port_queue_task(ap, atapi_packet_task, ap, 0);
+ ata_port_queue_task(ap, atapi_packet_task, qc, 0);
break;
default: