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Commit 86e45b6b authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
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[PATCH] libata: implement port_task 



Implement port_task.  LLDD's can schedule a function to be executed
with context after specified delay.  libata core takes care of
synchronization against EH.  This is generalized form of pio_task and
packet_task which are tied to PIO hsm implementation.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent d7fc3ca1

drivers/scsi/libata-core.c

+77 −0
Original line number Diff line number Diff line
@@ -721,6 +721,81 @@ static unsigned int ata_pio_modes(const struct ata_device *adev) 
	   timing API will get this right anyway */

}



/**

 *	ata_port_queue_task - Queue port_task

 *	@ap: The ata_port to queue port_task for

 *

 *	Schedule @fn(@data) for execution after @delay jiffies using

 *	port_task.  There is one port_task per port and it's the

 *	user(low level driver)'s responsibility to make sure that only

 *	one task is active at any given time.

 *

 *	libata core layer takes care of synchronization between

 *	port_task and EH.  ata_port_queue_task() may be ignored for EH

 *	synchronization.

 *

 *	LOCKING:

 *	Inherited from caller.

 */

void ata_port_queue_task(struct ata_port *ap, void (*fn)(void *), void *data,

			 unsigned long delay)

{

	int rc;



	if (ap->flags & ATA_FLAG_FLUSH_PIO_TASK)

		return;



	PREPARE_WORK(&ap->port_task, fn, data);



	if (!delay)

		rc = queue_work(ata_wq, &ap->port_task);

	else

		rc = queue_delayed_work(ata_wq, &ap->port_task, delay);



	/* rc == 0 means that another user is using port task */

	WARN_ON(rc == 0);

}



/**

 *	ata_port_flush_task - Flush port_task

 *	@ap: The ata_port to flush port_task for

 *

 *	After this function completes, port_task is guranteed not to

 *	be running or scheduled.

 *

 *	LOCKING:

 *	Kernel thread context (may sleep)

 */

void ata_port_flush_task(struct ata_port *ap)

{

	unsigned long flags;



	DPRINTK("ENTER\n");



	spin_lock_irqsave(&ap->host_set->lock, flags);

	ap->flags |= ATA_FLAG_FLUSH_PIO_TASK;

	spin_unlock_irqrestore(&ap->host_set->lock, flags);



	DPRINTK("flush #1\n");

	flush_workqueue(ata_wq);



	/*

	 * At this point, if a task is running, it's guaranteed to see

	 * the FLUSH flag; thus, it will never queue pio tasks again.

	 * Cancel and flush.

	 */

	if (!cancel_delayed_work(&ap->port_task)) {

		DPRINTK("flush #2\n");

		flush_workqueue(ata_wq);

	}



	spin_lock_irqsave(&ap->host_set->lock, flags);

	ap->flags &= ~ATA_FLAG_FLUSH_PIO_TASK;

	spin_unlock_irqrestore(&ap->host_set->lock, flags);



	DPRINTK("EXIT\n");

}



static inline void

ata_queue_packet_task(struct ata_port *ap)

{
@@ -4617,6 +4692,7 @@ static void ata_host_init(struct ata_port *ap, struct Scsi_Host *host, 
	ap->active_tag = ATA_TAG_POISON;

	ap->last_ctl = 0xFF;



	INIT_WORK(&ap->port_task, NULL, NULL);

	INIT_WORK(&ap->packet_task, atapi_packet_task, ap);

	INIT_WORK(&ap->pio_task, ata_pio_task, ap);

	INIT_LIST_HEAD(&ap->eh_done_q);
@@ -5088,6 +5164,7 @@ EXPORT_SYMBOL_GPL(ata_dev_revalidate); 
EXPORT_SYMBOL_GPL(ata_port_disable);

EXPORT_SYMBOL_GPL(ata_ratelimit);

EXPORT_SYMBOL_GPL(ata_busy_sleep);

EXPORT_SYMBOL_GPL(ata_port_queue_task);

EXPORT_SYMBOL_GPL(ata_scsi_ioctl);

EXPORT_SYMBOL_GPL(ata_scsi_queuecmd);

EXPORT_SYMBOL_GPL(ata_scsi_timed_out);

drivers/scsi/libata-scsi.c

+2 −0
Original line number Diff line number Diff line
@@ -785,6 +785,8 @@ int ata_scsi_error(struct Scsi_Host *host) 
	WARN_ON(ata_qc_from_tag(ap, ap->active_tag) == NULL);

	spin_unlock_irqrestore(&ap->host_set->lock, flags);



	ata_port_flush_task(ap);



	ap->ops->eng_timeout(ap);



	WARN_ON(host->host_failed || !list_empty(&host->eh_cmd_q));

drivers/scsi/libata.h

+1 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ extern int libata_fua; 
extern struct ata_queued_cmd *ata_qc_new_init(struct ata_port *ap,

				      struct ata_device *dev);

extern int ata_rwcmd_protocol(struct ata_queued_cmd *qc);

extern void ata_port_flush_task(struct ata_port *ap);

extern void ata_qc_free(struct ata_queued_cmd *qc);

extern unsigned int ata_qc_issue(struct ata_queued_cmd *qc);

extern int ata_check_atapi_dma(struct ata_queued_cmd *qc);

include/linux/libata.h

+4 −0
Original line number Diff line number Diff line
@@ -388,6 +388,8 @@ struct ata_port { 
	struct ata_host_stats	stats;

	struct ata_host_set	*host_set;



	struct work_struct	port_task;



	struct work_struct	packet_task;



	struct work_struct	pio_task;
@@ -515,6 +517,8 @@ extern int ata_ratelimit(void); 
extern unsigned int ata_busy_sleep(struct ata_port *ap,

				   unsigned long timeout_pat,

				   unsigned long timeout);

extern void ata_port_queue_task(struct ata_port *ap, void (*fn)(void *),

				void *data, unsigned long delay);



/*

 * Default driver ops implementations