[SCSI] ipr: improve interrupt service routine performance
During performance testing on P7 machines it was observed that the interrupt
service routine was doing unnecessary MMIO operations.
This patch rearranges the logic of the routine and moves some of the code out
of the main routine. The result is that there are now fewer MMIO operations in
the performance path of the code.
Signed-off-by: Wayne Boyer <wayneb@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 5244282..82ea4a8 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -4818,15 +4818,39 @@
/**
* ipr_handle_other_interrupt - Handle "other" interrupts
* @ioa_cfg: ioa config struct
- * @int_reg: interrupt register
*
* Return value:
* IRQ_NONE / IRQ_HANDLED
**/
-static irqreturn_t ipr_handle_other_interrupt(struct ipr_ioa_cfg *ioa_cfg,
- volatile u32 int_reg)
+static irqreturn_t ipr_handle_other_interrupt(struct ipr_ioa_cfg *ioa_cfg)
{
irqreturn_t rc = IRQ_HANDLED;
+ volatile u32 int_reg, int_mask_reg;
+
+ int_mask_reg = readl(ioa_cfg->regs.sense_interrupt_mask_reg32);
+ int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32) & ~int_mask_reg;
+
+ /* If an interrupt on the adapter did not occur, ignore it.
+ * Or in the case of SIS 64, check for a stage change interrupt.
+ */
+ if ((int_reg & IPR_PCII_OPER_INTERRUPTS) == 0) {
+ if (ioa_cfg->sis64) {
+ int_mask_reg = readl(ioa_cfg->regs.sense_interrupt_mask_reg);
+ int_reg = readl(ioa_cfg->regs.sense_interrupt_reg) & ~int_mask_reg;
+ if (int_reg & IPR_PCII_IPL_STAGE_CHANGE) {
+
+ /* clear stage change */
+ writel(IPR_PCII_IPL_STAGE_CHANGE, ioa_cfg->regs.clr_interrupt_reg);
+ int_reg = readl(ioa_cfg->regs.sense_interrupt_reg) & ~int_mask_reg;
+ list_del(&ioa_cfg->reset_cmd->queue);
+ del_timer(&ioa_cfg->reset_cmd->timer);
+ ipr_reset_ioa_job(ioa_cfg->reset_cmd);
+ return IRQ_HANDLED;
+ }
+ }
+
+ return IRQ_NONE;
+ }
if (int_reg & IPR_PCII_IOA_TRANS_TO_OPER) {
/* Mask the interrupt */
@@ -4887,7 +4911,7 @@
{
struct ipr_ioa_cfg *ioa_cfg = (struct ipr_ioa_cfg *)devp;
unsigned long lock_flags = 0;
- volatile u32 int_reg, int_mask_reg;
+ volatile u32 int_reg;
u32 ioasc;
u16 cmd_index;
int num_hrrq = 0;
@@ -4902,33 +4926,6 @@
return IRQ_NONE;
}
- int_mask_reg = readl(ioa_cfg->regs.sense_interrupt_mask_reg32);
- int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32) & ~int_mask_reg;
-
- /* If an interrupt on the adapter did not occur, ignore it.
- * Or in the case of SIS 64, check for a stage change interrupt.
- */
- if (unlikely((int_reg & IPR_PCII_OPER_INTERRUPTS) == 0)) {
- if (ioa_cfg->sis64) {
- int_mask_reg = readl(ioa_cfg->regs.sense_interrupt_mask_reg);
- int_reg = readl(ioa_cfg->regs.sense_interrupt_reg) & ~int_mask_reg;
- if (int_reg & IPR_PCII_IPL_STAGE_CHANGE) {
-
- /* clear stage change */
- writel(IPR_PCII_IPL_STAGE_CHANGE, ioa_cfg->regs.clr_interrupt_reg);
- int_reg = readl(ioa_cfg->regs.sense_interrupt_reg) & ~int_mask_reg;
- list_del(&ioa_cfg->reset_cmd->queue);
- del_timer(&ioa_cfg->reset_cmd->timer);
- ipr_reset_ioa_job(ioa_cfg->reset_cmd);
- spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
- return IRQ_HANDLED;
- }
- }
-
- spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
- return IRQ_NONE;
- }
-
while (1) {
ipr_cmd = NULL;
@@ -4968,7 +4965,7 @@
/* Clear the PCI interrupt */
do {
writel(IPR_PCII_HRRQ_UPDATED, ioa_cfg->regs.clr_interrupt_reg32);
- int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32) & ~int_mask_reg;
+ int_reg = readl(ioa_cfg->regs.sense_interrupt_reg32);
} while (int_reg & IPR_PCII_HRRQ_UPDATED &&
num_hrrq++ < IPR_MAX_HRRQ_RETRIES);
@@ -4983,7 +4980,7 @@
}
if (unlikely(rc == IRQ_NONE))
- rc = ipr_handle_other_interrupt(ioa_cfg, int_reg);
+ rc = ipr_handle_other_interrupt(ioa_cfg);
spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
return rc;
