[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: Robert Love <robert.w.love@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c
index 5b799a3..3591b87 100644 (file)
--- a/drivers/scsi/libfc/fc_fcp.c
+++ b/drivers/scsi/libfc/fc_fcp.c
@@ -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;
 }