[SCSI] qla2xxx: Resolve a performance issue in interrupt

Reverted back a change in qla*_intr_handler code that caused an increase in
cpu cycles by allowing interrupts to occur while the instance hardware lock
was being held.  Fix by taking the lock in irqsave mode.

Reported-and-tested-by: Douglas W. Styner <douglas.w.styner@intel.com>
Signed-off-by: Anirban Chakraborty <anirban.chakraborty@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index c8d0a176fea4..245e7afb4c4d 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -37,6 +37,7 @@ qla2100_intr_handler(int irq, void *dev_id)
         uint16_t        hccr;
         uint16_t        mb[4];
         struct rsp_que *rsp;
+        unsigned long   flags;
 
         rsp = (struct rsp_que *) dev_id;
         if (!rsp) {
@@ -49,7 +50,7 @@ qla2100_intr_handler(int irq, void *dev_id)
         reg = &ha->iobase->isp;
         status = 0;
 
-        spin_lock(&ha->hardware_lock);
+        spin_lock_irqsave(&ha->hardware_lock, flags);
         vha = pci_get_drvdata(ha->pdev);
         for (iter = 50; iter--; ) {
                 hccr = RD_REG_WORD(&reg->hccr);
@@ -101,7 +102,7 @@ qla2100_intr_handler(int irq, void *dev_id)
                         RD_REG_WORD(&reg->hccr);
                 }
         }
-        spin_unlock(&ha->hardware_lock);
+        spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
         if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
             (status & MBX_INTERRUPT) && ha->flags.mbox_int) {
@@ -133,6 +134,7 @@ qla2300_intr_handler(int irq, void *dev_id)
         uint16_t        mb[4];
         struct rsp_que *rsp;
         struct qla_hw_data *ha;
+        unsigned long   flags;
 
         rsp = (struct rsp_que *) dev_id;
         if (!rsp) {
@@ -145,7 +147,7 @@ qla2300_intr_handler(int irq, void *dev_id)
         reg = &ha->iobase->isp;
         status = 0;
 
-        spin_lock(&ha->hardware_lock);
+        spin_lock_irqsave(&ha->hardware_lock, flags);
         vha = pci_get_drvdata(ha->pdev);
         for (iter = 50; iter--; ) {
                 stat = RD_REG_DWORD(&reg->u.isp2300.host_status);
@@ -216,7 +218,7 @@ qla2300_intr_handler(int irq, void *dev_id)
                 WRT_REG_WORD(&reg->hccr, HCCR_CLR_RISC_INT);
                 RD_REG_WORD_RELAXED(&reg->hccr);
         }
-        spin_unlock(&ha->hardware_lock);
+        spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
         if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
             (status & MBX_INTERRUPT) && ha->flags.mbox_int) {
@@ -1626,6 +1628,7 @@ qla24xx_intr_handler(int irq, void *dev_id)
         uint32_t        hccr;
         uint16_t        mb[4];
         struct rsp_que *rsp;
+        unsigned long   flags;
 
         rsp = (struct rsp_que *) dev_id;
         if (!rsp) {
@@ -1638,7 +1641,7 @@ qla24xx_intr_handler(int irq, void *dev_id)
         reg = &ha->iobase->isp24;
         status = 0;
 
-        spin_lock(&ha->hardware_lock);
+        spin_lock_irqsave(&ha->hardware_lock, flags);
         vha = pci_get_drvdata(ha->pdev);
         for (iter = 50; iter--; ) {
                 stat = RD_REG_DWORD(&reg->host_status);
@@ -1688,7 +1691,7 @@ qla24xx_intr_handler(int irq, void *dev_id)
                 WRT_REG_DWORD(&reg->hccr, HCCRX_CLR_RISC_INT);
                 RD_REG_DWORD_RELAXED(&reg->hccr);
         }
-        spin_unlock(&ha->hardware_lock);
+        spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
         if (test_bit(MBX_INTR_WAIT, &ha->mbx_cmd_flags) &&
             (status & MBX_INTERRUPT) && ha->flags.mbox_int) {