[SCSI] ipr: reverse the isr optimization changes

The isr optimization patch that was submitted a few months ago
exposed problems with receiving and handling spurious HRRQ interrutps.

commit 64ffdb762241c0a9c0c8fac7ea92aa0ba1529334
Author: Wayne Boyer <wayneb@linux.vnet.ibm.com>
Date:   Wed May 19 11:56:13 2010 -0700

    [SCSI] ipr: improve interrupt service routine performance

That patch is reverted with this one.  A new patch will be submitted
once the issue is better understood and properly handled in the driver.

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>

1 files changed, 33 insertions, 30 deletions

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 67875d41345f..3b28e8728131 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -4939,39 +4939,15 @@ static int ipr_eh_abort(struct scsi_cmnd * scsi_cmd)
 /**
  * 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)
+static irqreturn_t ipr_handle_other_interrupt(struct ipr_ioa_cfg *ioa_cfg,
+                                              volatile u32 int_reg)
 {
         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 */
@@ -5032,7 +5008,7 @@ static irqreturn_t ipr_isr(int irq, void *devp)
 {
         struct ipr_ioa_cfg *ioa_cfg = (struct ipr_ioa_cfg *)devp;
         unsigned long lock_flags = 0;
-        volatile u32 int_reg;
+        volatile u32 int_reg, int_mask_reg;
         u32 ioasc;
         u16 cmd_index;
         int num_hrrq = 0;
@@ -5047,6 +5023,33 @@ static irqreturn_t ipr_isr(int irq, void *devp)
                 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;
 
@@ -5086,7 +5089,7 @@ static irqreturn_t ipr_isr(int irq, void *devp)
                         /* 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_reg = readl(ioa_cfg->regs.sense_interrupt_reg32) & ~int_mask_reg;
                         } while (int_reg & IPR_PCII_HRRQ_UPDATED &&
                                         num_hrrq++ < IPR_MAX_HRRQ_RETRIES);
 
@@ -5101,7 +5104,7 @@ static irqreturn_t ipr_isr(int irq, void *devp)
         }
 
         if (unlikely(rc == IRQ_NONE))
-                rc = ipr_handle_other_interrupt(ioa_cfg);
+                rc = ipr_handle_other_interrupt(ioa_cfg, int_reg);
 
         spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
         return rc;