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[PATCH] libata: pass qc around intead of ap during PIO
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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>
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Tejun Heo authored and Jeff Garzik committed Apr 2, 2006
1 parent 2719736 commit c91af2c
Showing 1 changed file with 26 additions and 45 deletions.
71 changes: 26 additions & 45 deletions drivers/scsi/libata-core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3416,25 +3416,21 @@ void ata_poll_qc_complete(struct ata_queued_cmd *qc)

/**
* 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)
*
* 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:
Expand Down Expand Up @@ -3468,18 +3464,17 @@ static unsigned long ata_pio_poll(struct ata_port *ap)

/**
* 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)
*
* 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;

/*
Expand All @@ -3500,9 +3495,6 @@ static int ata_pio_complete (struct ata_port *ap)
}
}

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);
Expand Down Expand Up @@ -3838,15 +3830,14 @@ static void atapi_pio_bytes(struct ata_queued_cmd *qc)

/**
* 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;

/*
Expand All @@ -3868,9 +3859,6 @@ static void ata_pio_block(struct ata_port *ap)
}
}

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;
Expand Down Expand Up @@ -3899,12 +3887,9 @@ static void ata_pio_block(struct ata_port *ap)
}
}

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",
Expand All @@ -3922,7 +3907,8 @@ static void ata_pio_error(struct ata_port *ap)

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;

Expand All @@ -3935,33 +3921,33 @@ static void ata_pio_task(void *_data)
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.
Expand All @@ -3972,17 +3958,12 @@ static void ata_pio_task(void *_data)
* 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)) {
Expand Down Expand Up @@ -4022,7 +4003,7 @@ static void atapi_packet_task(void *_data)

/* 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;
Expand Down Expand Up @@ -4328,26 +4309,26 @@ unsigned int ata_qc_issue_prot(struct ata_queued_cmd *qc)
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:
Expand Down

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