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[SCSI] qla2xxx: Resolve a performance issue in interrupt
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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>
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Anirban Chakraborty authored and James Bottomley committed Jun 15, 2009
1 parent babdb78 commit 43fac4d
Showing 1 changed file with 9 additions and 6 deletions.
15 changes: 9 additions & 6 deletions drivers/scsi/qla2xxx/qla_isr.c
Original file line number Diff line number Diff line change
Expand Up @@ -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) {
Expand All @@ -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);
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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) {
Expand All @@ -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);
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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) {
Expand All @@ -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);
Expand Down Expand Up @@ -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) {
Expand Down

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