[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>

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 67875d4..3b28e87 100644 (file)
--- 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;