[PATCH v4 21/40] sfc: optimize the driver by using atomic find_bit() API

[Yury Norov]

SFC code traverses rps_slot_map and rxq_retry_mask bit by bit. Simplify
it by using dedicated atomic find_bit() functions, as they skip already
clear bits.

Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
Reviewed-by: Edward Cree <ecree.xilinx@xxxxxxxxx>
---
 drivers/net/ethernet/sfc/rx_common.c         |  5 ++---
 drivers/net/ethernet/sfc/siena/rx_common.c   |  5 ++---
 drivers/net/ethernet/sfc/siena/siena_sriov.c | 15 +++++++--------
 3 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/sfc/rx_common.c b/drivers/net/ethernet/sfc/rx_common.c
index dcd901eccfc8..370a2d20ccfb 100644
--- a/drivers/net/ethernet/sfc/rx_common.c
+++ b/drivers/net/ethernet/sfc/rx_common.c
@@ -9,6 +9,7 @@
  */
 
 #include "net_driver.h"
+#include <linux/find_atomic.h>
 #include <linux/module.h>
 #include <linux/iommu.h>
 #include <net/rps.h>
@@ -953,9 +954,7 @@ int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
 	int rc;
 
 	/* find a free slot */
-	for (slot_idx = 0; slot_idx < EFX_RPS_MAX_IN_FLIGHT; slot_idx++)
-		if (!test_and_set_bit(slot_idx, &efx->rps_slot_map))
-			break;
+	slot_idx = find_and_set_bit(&efx->rps_slot_map, EFX_RPS_MAX_IN_FLIGHT);
 	if (slot_idx >= EFX_RPS_MAX_IN_FLIGHT)
 		return -EBUSY;
 
diff --git a/drivers/net/ethernet/sfc/siena/rx_common.c b/drivers/net/ethernet/sfc/siena/rx_common.c
index 219fb358a646..fc1d4d02beb6 100644
--- a/drivers/net/ethernet/sfc/siena/rx_common.c
+++ b/drivers/net/ethernet/sfc/siena/rx_common.c
@@ -9,6 +9,7 @@
  */
 
 #include "net_driver.h"
+#include <linux/find_atomic.h>
 #include <linux/module.h>
 #include <linux/iommu.h>
 #include <net/rps.h>
@@ -959,9 +960,7 @@ int efx_siena_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
 	int rc;
 
 	/* find a free slot */
-	for (slot_idx = 0; slot_idx < EFX_RPS_MAX_IN_FLIGHT; slot_idx++)
-		if (!test_and_set_bit(slot_idx, &efx->rps_slot_map))
-			break;
+	slot_idx = find_and_set_bit(&efx->rps_slot_map, EFX_RPS_MAX_IN_FLIGHT);
 	if (slot_idx >= EFX_RPS_MAX_IN_FLIGHT)
 		return -EBUSY;
 
diff --git a/drivers/net/ethernet/sfc/siena/siena_sriov.c b/drivers/net/ethernet/sfc/siena/siena_sriov.c
index 8353c15dc233..f643413f9c20 100644
--- a/drivers/net/ethernet/sfc/siena/siena_sriov.c
+++ b/drivers/net/ethernet/sfc/siena/siena_sriov.c
@@ -3,6 +3,7 @@
  * Driver for Solarflare network controllers and boards
  * Copyright 2010-2012 Solarflare Communications Inc.
  */
+#include <linux/find_atomic.h>
 #include <linux/pci.h>
 #include <linux/module.h>
 #include "net_driver.h"
@@ -722,14 +723,12 @@ static int efx_vfdi_fini_all_queues(struct siena_vf *vf)
 					     efx_vfdi_flush_wake(vf),
 					     timeout);
 		rxqs_count = 0;
-		for (index = 0; index < count; ++index) {
-			if (test_and_clear_bit(index, vf->rxq_retry_mask)) {
-				atomic_dec(&vf->rxq_retry_count);
-				MCDI_SET_ARRAY_DWORD(
-					inbuf, FLUSH_RX_QUEUES_IN_QID_OFST,
-					rxqs_count, vf_offset + index);
-				rxqs_count++;
-			}
+		for_each_test_and_clear_bit(index, vf->rxq_retry_mask, count) {
+			atomic_dec(&vf->rxq_retry_count);
+			MCDI_SET_ARRAY_DWORD(
+				inbuf, FLUSH_RX_QUEUES_IN_QID_OFST,
+				rxqs_count, vf_offset + index);
+			rxqs_count++;
 		}
 	}
 
-- 
2.43.0