Commit 312d3e56 authored by Dan Williams's avatar Dan Williams Committed by James Bottomley
Browse files

[SCSI] libsas: remove ata_port.lock management duties from lldds 



Each libsas driver (mvsas, pm8001, and isci) has invented a different
method for managing the ap->lock.  The lock is held by the ata
->queuecommand() path.  mvsas drops it prior to acquiring any internal
locks which allows it to hold its internal lock across calls to
task->task_done().  This capability is important as it is the only way
the driver can flush task->task_done() instances to guarantee that it no
longer has any in-flight references to a domain_device at
->lldd_dev_gone() time.

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent b1124cd3

drivers/scsi/isci/request.c

+1 −2
Original line number Diff line number Diff line
@@ -3796,8 +3796,7 @@ int isci_request_execute(struct isci_host *ihost, struct isci_remote_device *ide 
		/* Cause this task to be scheduled in the SCSI error

		 * handler thread.

		 */

		isci_execpath_callback(ihost, task,

				       sas_task_abort);

		sas_task_abort(task);



		/* Change the status, since we are holding

		 * the I/O until it is managed by the SCSI

drivers/scsi/isci/task.c

+2 −4
Original line number Diff line number Diff line
@@ -96,8 +96,7 @@ static void isci_task_refuse(struct isci_host *ihost, struct sas_task *task, 
			__func__, task, response, status);



		task->lldd_task = NULL;



		isci_execpath_callback(ihost, task, task->task_done);

		task->task_done(task);

		break;



	case isci_perform_aborted_io_completion:
@@ -117,8 +116,7 @@ static void isci_task_refuse(struct isci_host *ihost, struct sas_task *task, 
			"%s: Error - task = %p, response=%d, "

			"status=%d\n",

			__func__, task, response, status);



		isci_execpath_callback(ihost, task, sas_task_abort);

		sas_task_abort(task);

		break;



	default:

drivers/scsi/isci/task.h

+0 −36
Original line number Diff line number Diff line
@@ -321,40 +321,4 @@ isci_task_set_completion_status( 
	return task_notification_selection;



}

/**

* isci_execpath_callback() - This function is called from the task

* execute path when the task needs to callback libsas about the submit-time

* task failure.  The callback occurs either through the task's done function

* or through sas_task_abort.  In the case of regular non-discovery SATA/STP I/O

* requests, libsas takes the host lock before calling execute task.  Therefore

* in this situation the host lock must be managed before calling the func.

*

* @ihost: This parameter is the controller to which the I/O request was sent.

* @task: This parameter is the I/O request.

* @func: This parameter is the function to call in the correct context.

* @status: This parameter is the status code for the completed task.

*

*/

static inline void isci_execpath_callback(struct isci_host *ihost,

					  struct sas_task  *task,

					  void (*func)(struct sas_task *))

{

	struct domain_device *dev = task->dev;



	if (dev_is_sata(dev) && task->uldd_task) {

		unsigned long flags;



		/* Since we are still in the submit path, and since

		 * libsas takes the host lock on behalf of SATA

		 * devices before I/O starts (in the non-discovery case),

		 * we need to unlock before we can call the callback function.

		 */

		raw_local_irq_save(flags);

		spin_unlock(dev->sata_dev.ap->lock);

		func(task);

		spin_lock(dev->sata_dev.ap->lock);

		raw_local_irq_restore(flags);

	} else

		func(task);

}

#endif /* !defined(_SCI_TASK_H_) */

drivers/scsi/libsas/sas_ata.c

+23 −13
Original line number Diff line number Diff line
@@ -166,23 +166,30 @@ qc_already_gone: 


static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)

{

	int res;

	unsigned long flags;

	struct sas_task *task;

	struct domain_device *dev = qc->ap->private_data;

	struct scatterlist *sg;

	int ret = AC_ERR_SYSTEM;

	unsigned int si, xfer = 0;

	struct ata_port *ap = qc->ap;

	struct domain_device *dev = ap->private_data;

	struct sas_ha_struct *sas_ha = dev->port->ha;

	struct Scsi_Host *host = sas_ha->core.shost;

	struct sas_internal *i = to_sas_internal(host->transportt);

	struct scatterlist *sg;

	unsigned int xfer = 0;

	unsigned int si;



	/* TODO: audit callers to ensure they are ready for qc_issue to

	 * unconditionally re-enable interrupts

	 */

	local_irq_save(flags);

	spin_unlock(ap->lock);



	/* If the device fell off, no sense in issuing commands */

	if (dev->gone)

		return AC_ERR_SYSTEM;

		goto out;



	task = sas_alloc_task(GFP_ATOMIC);

	if (!task)

		return AC_ERR_SYSTEM;

		goto out;

	task->dev = dev;

	task->task_proto = SAS_PROTOCOL_STP;

	task->task_done = sas_ata_task_done;
@@ -227,21 +234,24 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc) 
		ASSIGN_SAS_TASK(qc->scsicmd, task);



	if (sas_ha->lldd_max_execute_num < 2)

		res = i->dft->lldd_execute_task(task, 1, GFP_ATOMIC);

		ret = i->dft->lldd_execute_task(task, 1, GFP_ATOMIC);

	else

		res = sas_queue_up(task);

		ret = sas_queue_up(task);



	/* Examine */

	if (res) {

		SAS_DPRINTK("lldd_execute_task returned: %d\n", res);

	if (ret) {

		SAS_DPRINTK("lldd_execute_task returned: %d\n", ret);



		if (qc->scsicmd)

			ASSIGN_SAS_TASK(qc->scsicmd, NULL);

		sas_free_task(task);

		return AC_ERR_SYSTEM;

		ret = AC_ERR_SYSTEM;

	}



	return 0;

 out:

	spin_lock(ap->lock);

	local_irq_restore(flags);

	return ret;

}



static bool sas_ata_qc_fill_rtf(struct ata_queued_cmd *qc)

drivers/scsi/libsas/sas_scsi_host.c

+2 −4
Original line number Diff line number Diff line
@@ -198,11 +198,9 @@ int sas_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) 
	}



	if (dev_is_sata(dev)) {

		unsigned long flags;



		spin_lock_irqsave(dev->sata_dev.ap->lock, flags);

		spin_lock_irq(dev->sata_dev.ap->lock);

		res = ata_sas_queuecmd(cmd, dev->sata_dev.ap);

		spin_unlock_irqrestore(dev->sata_dev.ap->lock, flags);

		spin_unlock_irq(dev->sata_dev.ap->lock);

		return res;

	}

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