commit 43fac4d97a1a30085f1cae61aa565e5e7e5e5d7d
author Anirban Chakraborty <anirban.chakraborty@qlogic.com> Wed Jun 10 13:55:11 2009 -0700
committer James Bottomley <James.Bottomley@HansenPartnership.com> Mon Jun 15 10:09:32 2009 -0500
tree 52a532aac2f925bc104bc78aab29727fd3a29742
parent babdb788f7ec1a782a52240a5f6dae568f32565f

[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>

drivers/scsi/qla2xxx/qla_isr.c

diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index c8d0a17..245e7af 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -37,6 +37,7 @@
 	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 @@
 	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 @@
 			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 @@
 	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 @@
 	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 @@
 		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 @@
 	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 @@
 	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 @@
 		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) {