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Commit 9c8cce8e authored by Robert Love's avatar Robert Love Committed by James Bottomley
Browse files

[SCSI] libfc: Move host_lock usage into ramp_up/down routines 



The host_lock is still used to protect the can_queue
value in the Scsi_Host, but it doesn't need to be held
and released by each caller. This patch moves the lock
usage into the fc_fcp_can_queue_ramp_up and
fc_fcp_can_queue_ramp_down routines.

Signed-off-by: default avatarRobert Love <robert.w.love@intel.com>
Tested-by: default avatarRoss Brattain <ross.b.brattain@intel.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent 63ce2499

drivers/scsi/libfc/fc_fcp.c

+15 −10
Original line number Diff line number Diff line
@@ -335,22 +335,23 @@ static void fc_fcp_ddp_done(struct fc_fcp_pkt *fsp) 
/**

 * fc_fcp_can_queue_ramp_up() - increases can_queue

 * @lport: lport to ramp up can_queue

 *

 * Locking notes: Called with Scsi_Host lock held

 */

static void fc_fcp_can_queue_ramp_up(struct fc_lport *lport)

{

	struct fc_fcp_internal *si = fc_get_scsi_internal(lport);

	unsigned long flags;

	int can_queue;



	spin_lock_irqsave(lport->host->host_lock, flags);



	if (si->last_can_queue_ramp_up_time &&

	    (time_before(jiffies, si->last_can_queue_ramp_up_time +

			 FC_CAN_QUEUE_PERIOD)))

		return;

		goto unlock;



	if (time_before(jiffies, si->last_can_queue_ramp_down_time +

			FC_CAN_QUEUE_PERIOD))

		return;

		goto unlock;



	si->last_can_queue_ramp_up_time = jiffies;
@@ -362,6 +363,9 @@ static void fc_fcp_can_queue_ramp_up(struct fc_lport *lport) 
	lport->host->can_queue = can_queue;

	shost_printk(KERN_ERR, lport->host, "libfc: increased "

		     "can_queue to %d.\n", can_queue);



unlock:

	spin_unlock_irqrestore(lport->host->host_lock, flags);

}



/**
@@ -373,18 +377,19 @@ static void fc_fcp_can_queue_ramp_up(struct fc_lport *lport) 
 * commands complete or timeout, then try again with a reduced

 * can_queue. Eventually we will hit the point where we run

 * on all reserved structs.

 *

 * Locking notes: Called with Scsi_Host lock held

 */

static void fc_fcp_can_queue_ramp_down(struct fc_lport *lport)

{

	struct fc_fcp_internal *si = fc_get_scsi_internal(lport);

	unsigned long flags;

	int can_queue;



	spin_lock_irqsave(lport->host->host_lock, flags);



	if (si->last_can_queue_ramp_down_time &&

	    (time_before(jiffies, si->last_can_queue_ramp_down_time +

			 FC_CAN_QUEUE_PERIOD)))

		return;

		goto unlock;



	si->last_can_queue_ramp_down_time = jiffies;
@@ -395,6 +400,9 @@ static void fc_fcp_can_queue_ramp_down(struct fc_lport *lport) 
	lport->host->can_queue = can_queue;

	shost_printk(KERN_ERR, lport->host, "libfc: Could not allocate frame.\n"

		     "Reducing can_queue to %d.\n", can_queue);



unlock:

	spin_unlock_irqrestore(lport->host->host_lock, flags);

}



/*
@@ -409,16 +417,13 @@ static inline struct fc_frame *fc_fcp_frame_alloc(struct fc_lport *lport, 
						  size_t len)

{

	struct fc_frame *fp;

	unsigned long flags;



	fp = fc_frame_alloc(lport, len);

	if (likely(fp))

		return fp;



	/* error case */

	spin_lock_irqsave(lport->host->host_lock, flags);

	fc_fcp_can_queue_ramp_down(lport);

	spin_unlock_irqrestore(lport->host->host_lock, flags);

	return NULL;

}