PWN-Hunter/android_kernel_xiaomi_sdm845
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[PATCH] libata irq-pio: eliminate unnecessary queuing in ata_pio_first_block()

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- change the return value of ata_pio_complete() 0 <-> 1
   - add return value for ata_pio_first_block()
   - rename variable "qc_completed" to "has_next" in ata_pio_task()
   - use has_next to eliminate unnecessary queuing in ata_pio_first_block()

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>

==========
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
This commit is contained in:
Albert Lee 2005-11-01 19:30:05 +08:00 committed by Jeff Garzik
parent e27486db89
commit fbcdd80b0d
1 changed files with 33 additions and 20 deletions
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53
drivers/scsi/libata-core.c
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@ -2790,7 +2790,8 @@ static unsigned long ata_pio_poll(struct ata_port *ap)
* None. (executing in kernel thread context)
*
* RETURNS:
* Non-zero if qc completed, zero otherwise.
* Zero if qc completed.
* Non-zero if has next.
*/
static int ata_pio_complete (struct ata_port *ap)
@ -2812,14 +2813,14 @@ static int ata_pio_complete (struct ata_port *ap)
if (drv_stat & (ATA_BUSY | ATA_DRQ)) {
ap->hsm_task_state = HSM_ST_LAST_POLL;
ap->pio_task_timeout = jiffies + ATA_TMOUT_PIO;
return 0;
return 1;
}
}
drv_stat = ata_wait_idle(ap);
if (!ata_ok(drv_stat)) {
ap->hsm_task_state = HSM_ST_ERR;
return 0;
return 1;
}
qc = ata_qc_from_tag(ap, ap->active_tag);
@ -2831,7 +2832,7 @@ static int ata_pio_complete (struct ata_port *ap)
/* another command may start at this point */
return 1;
return 0;
}
@ -3068,27 +3069,42 @@ static void atapi_send_cdb(struct ata_port *ap, struct ata_queued_cmd *qc)
*
* LOCKING:
* Kernel thread context (may sleep)
*
* RETURNS:
* Zero if irq handler takes over
* Non-zero if has next (polling).
*/
static void ata_pio_first_block(struct ata_port *ap)
static int ata_pio_first_block(struct ata_port *ap)
{
struct ata_queued_cmd *qc;
u8 status;
unsigned long flags;
int has_next;
qc = ata_qc_from_tag(ap, ap->active_tag);
assert(qc != NULL);
assert(qc->flags & ATA_QCFLAG_ACTIVE);
/* if polling, we will stay in the work queue after sending the data.
* otherwise, interrupt handler takes over after sending the data.
*/
has_next = (qc->tf.flags & ATA_TFLAG_POLLING);
/* sleep-wait for BSY to clear */
DPRINTK("busy wait\n");
if (ata_busy_sleep(ap, ATA_TMOUT_DATAOUT_QUICK, ATA_TMOUT_DATAOUT))
if (ata_busy_sleep(ap, ATA_TMOUT_DATAOUT_QUICK, ATA_TMOUT_DATAOUT)) {
ap->hsm_task_state = HSM_ST_TMOUT;
goto err_out;
}
/* make sure DRQ is set */
status = ata_chk_status(ap);
if ((status & (ATA_BUSY | ATA_DRQ)) != ATA_DRQ)
if ((status & (ATA_BUSY | ATA_DRQ)) != ATA_DRQ) {
/* device status error */
ap->hsm_task_state = HSM_ST_ERR;
goto err_out;
}
/* Send the CDB (atapi) or the first data block (ata pio out).
* During the state transition, interrupt handler shouldn't
@ -3112,18 +3128,15 @@ static void ata_pio_first_block(struct ata_port *ap)
/* send CDB */
atapi_send_cdb(ap, qc);
spin_unlock_irqrestore(&ap->host_set->lock, flags);
/* 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);
return;
return has_next;
err_out:
ata_pio_error(ap);
return 1; /* has next */
}
/**
@ -3338,23 +3351,23 @@ static void ata_pio_task(void *_data)
{
struct ata_port *ap = _data;
unsigned long timeout;
int qc_completed;
int has_next;
fsm_start:
timeout = 0;
qc_completed = 0;
has_next = 1;
switch (ap->hsm_task_state) {
case HSM_ST_FIRST:
ata_pio_first_block(ap);
return;
has_next = ata_pio_first_block(ap);
break;
case HSM_ST:
ata_pio_block(ap);
break;
case HSM_ST_LAST:
qc_completed = ata_pio_complete(ap);
has_next = ata_pio_complete(ap);
break;
case HSM_ST_POLL:
@ -3374,7 +3387,7 @@ static void ata_pio_task(void *_data)
if (timeout)
queue_delayed_work(ata_wq, &ap->pio_task, timeout);
else if (!qc_completed)
else if (has_next)
goto fsm_start;
}