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[PATCH] libata: implement ata_poll_qc_complete and use it in polling functions 

[PATCH libata-dev-2.6:upstream] implement ata_poll_qc_complete and use it in polling functions

 Previously, libata polling functions turned irq back on and completed
qc commands without holding host lock.  This creates a race condition
between the polling task and interrupts from other ports on the same
host set or spurious interrupt from itself.

 This patch implements ata_poll_qc_complete which enables irq and
completes qc atomically and convert all polling functions.

 Note: atapi_packet_task() didn't use to turn irq back on or clear
ATA_FLAG_NOINTR on error exits.  This patch makes it use
ata_poll_qc_complete which does both.

 Note: With this change, ALL invocations of ata_qc_complete() are now
done under host_set lock.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
This commit is contained in:
Tejun Heo 2005-08-22 17:12:45 +09:00 committed by Jeff Garzik
parent c138950371
commit 40e8c82c74
1 changed files with 24 additions and 10 deletions
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34
drivers/scsi/libata-core.c
View File

@ -2401,6 +2401,26 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
return 0;
}
/**
* ata_poll_qc_complete - turn irq back on and finish qc
* @qc: Command to complete
* @drv_stat: ATA status register content
*
* LOCKING:
* None. (grabs host lock)
*/
void ata_poll_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
{
struct ata_port *ap = qc->ap;
spin_lock_irq(&ap->host_set->lock);
ap->flags &= ~ATA_FLAG_NOINTR;
ata_irq_on(ap);
ata_qc_complete(qc, drv_stat);
spin_unlock_irq(&ap->host_set->lock);
}
/**
* ata_pio_poll -
* @ap:
@ -2492,9 +2512,7 @@ static void ata_pio_complete (struct ata_port *ap)
ap->pio_task_state = PIO_ST_IDLE;
ata_irq_on(ap);
ata_qc_complete(qc, drv_stat);
ata_poll_qc_complete(qc, drv_stat);
}
@ -2844,9 +2862,7 @@ static void ata_pio_block(struct ata_port *ap)
if ((status & ATA_DRQ) == 0) {
ap->pio_task_state = PIO_ST_IDLE;
ata_irq_on(ap);
ata_qc_complete(qc, status);
ata_poll_qc_complete(qc, status);
return;
}
@ -2876,9 +2892,7 @@ static void ata_pio_error(struct ata_port *ap)
ap->pio_task_state = PIO_ST_IDLE;
ata_irq_on(ap);
ata_qc_complete(qc, drv_stat | ATA_ERR);
ata_poll_qc_complete(qc, drv_stat | ATA_ERR);
}
static void ata_pio_task(void *_data)
@ -3791,7 +3805,7 @@ static void atapi_packet_task(void *_data)
return;
err_out:
ata_qc_complete(qc, ATA_ERR);
ata_poll_qc_complete(qc, ATA_ERR);
}