IB/qib: Add percpu counter replacing qib_devdata int_counter

This patch replaces the dd->int_counter with a percpu counter.

The maintanance of qib_stats.sps_ints and int_counter are
combined into the new counter.

There are two new functions added to read the counter:
- qib_int_counter (for a particular qib_devdata)
- qib_sps_ints (for all HCAs)

A z_int_counter is added to allow the interrupt detection logic
to determine if interrupts have occured since z_int_counter
was "reset".

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 9 insertions, 22 deletions

diff --git a/drivers/infiniband/hw/qib/qib_iba7322.c b/drivers/infiniband/hw/qib/qib_iba7322.c
index d1bd21319d7d..8441579decd9 100644
--- a/drivers/infiniband/hw/qib/qib_iba7322.c
+++ b/drivers/infiniband/hw/qib/qib_iba7322.c
@@ -3115,9 +3115,7 @@ static irqreturn_t qib_7322intr(int irq, void *data)
 		goto bail;
 	}
 
-	qib_stats.sps_ints++;
-	if (dd->int_counter != (u32) -1)
-		dd->int_counter++;
+	this_cpu_inc(*dd->int_counter);
 
 	/* handle "errors" of various kinds first, device ahead of port */
 	if (unlikely(istat & (~QIB_I_BITSEXTANT | QIB_I_GPIO |
@@ -3186,9 +3184,7 @@ static irqreturn_t qib_7322pintr(int irq, void *data)
 		 */
 		return IRQ_HANDLED;
 
-	qib_stats.sps_ints++;
-	if (dd->int_counter != (u32) -1)
-		dd->int_counter++;
+	this_cpu_inc(*dd->int_counter);
 
 	/* Clear the interrupt bit we expect to be set. */
 	qib_write_kreg(dd, kr_intclear, ((1ULL << QIB_I_RCVAVAIL_LSB) |
@@ -3215,9 +3211,7 @@ static irqreturn_t qib_7322bufavail(int irq, void *data)
 		 */
 		return IRQ_HANDLED;
 
-	qib_stats.sps_ints++;
-	if (dd->int_counter != (u32) -1)
-		dd->int_counter++;
+	this_cpu_inc(*dd->int_counter);
 
 	/* Clear the interrupt bit we expect to be set. */
 	qib_write_kreg(dd, kr_intclear, QIB_I_SPIOBUFAVAIL);
@@ -3248,9 +3242,7 @@ static irqreturn_t sdma_intr(int irq, void *data)
 		 */
 		return IRQ_HANDLED;
 
-	qib_stats.sps_ints++;
-	if (dd->int_counter != (u32) -1)
-		dd->int_counter++;
+	this_cpu_inc(*dd->int_counter);
 
 	/* Clear the interrupt bit we expect to be set. */
 	qib_write_kreg(dd, kr_intclear, ppd->hw_pidx ?
@@ -3277,9 +3269,7 @@ static irqreturn_t sdma_idle_intr(int irq, void *data)
 		 */
 		return IRQ_HANDLED;
 
-	qib_stats.sps_ints++;
-	if (dd->int_counter != (u32) -1)
-		dd->int_counter++;
+	this_cpu_inc(*dd->int_counter);
 
 	/* Clear the interrupt bit we expect to be set. */
 	qib_write_kreg(dd, kr_intclear, ppd->hw_pidx ?
@@ -3306,9 +3296,7 @@ static irqreturn_t sdma_progress_intr(int irq, void *data)
 		 */
 		return IRQ_HANDLED;
 
-	qib_stats.sps_ints++;
-	if (dd->int_counter != (u32) -1)
-		dd->int_counter++;
+	this_cpu_inc(*dd->int_counter);
 
 	/* Clear the interrupt bit we expect to be set. */
 	qib_write_kreg(dd, kr_intclear, ppd->hw_pidx ?
@@ -3336,9 +3324,7 @@ static irqreturn_t sdma_cleanup_intr(int irq, void *data)
 		 */
 		return IRQ_HANDLED;
 
-	qib_stats.sps_ints++;
-	if (dd->int_counter != (u32) -1)
-		dd->int_counter++;
+	this_cpu_inc(*dd->int_counter);
 
 	/* Clear the interrupt bit we expect to be set. */
 	qib_write_kreg(dd, kr_intclear, ppd->hw_pidx ?
@@ -3723,7 +3709,8 @@ static int qib_do_7322_reset(struct qib_devdata *dd)
 	dd->pport->cpspec->ibsymdelta = 0;
 	dd->pport->cpspec->iblnkerrdelta = 0;
 	dd->pport->cpspec->ibmalfdelta = 0;
-	dd->int_counter = 0; /* so we check interrupts work again */
+	/* so we check interrupts work again */
+	dd->z_int_counter = qib_int_counter(dd);
 
 	/*
 	 * Keep chip from being accessed until we are ready.  Use