netdev - [PATCH v3 21/35] sfc: optimize the driver by using atomic find

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Date: Mon, 11 Dec 2023 18:27:35 -0800
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
	Edward Cree <ecree.xilinx@...il.com>,
	Martin Habets <habetsm.xilinx@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Yury Norov <yury.norov@...il.com>,
	netdev@...r.kernel.org,
	linux-net-drivers@....com
Cc: Jan Kara <jack@...e.cz>,
	Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
	Matthew Wilcox <willy@...radead.org>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Maxim Kuvyrkov <maxim.kuvyrkov@...aro.org>,
	Alexey Klimov <klimov.linux@...il.com>,
	Bart Van Assche <bvanassche@....org>,
	Sergey Shtylyov <s.shtylyov@....ru>
Subject: [PATCH v3 21/35] sfc: optimize the driver by using atomic find_bit() API

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@...il.com>
Reviewed-by: Edward Cree <ecree.xilinx@...il.com>
---
 drivers/net/ethernet/sfc/rx_common.c         |  4 +---
 drivers/net/ethernet/sfc/siena/rx_common.c   |  4 +---
 drivers/net/ethernet/sfc/siena/siena_sriov.c | 14 ++++++--------
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/sfc/rx_common.c b/drivers/net/ethernet/sfc/rx_common.c
index d2f35ee15eff..0112968b3fe7 100644
--- a/drivers/net/ethernet/sfc/rx_common.c
+++ b/drivers/net/ethernet/sfc/rx_common.c
@@ -950,9 +950,7 @@ 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 4579f43484c3..160b16aa7486 100644
--- a/drivers/net/ethernet/sfc/siena/rx_common.c
+++ b/drivers/net/ethernet/sfc/siena/rx_common.c
@@ -958,9 +958,7 @@ 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..554b799288b8 100644
--- a/drivers/net/ethernet/sfc/siena/siena_sriov.c
+++ b/drivers/net/ethernet/sfc/siena/siena_sriov.c
@@ -722,14 +722,12 @@ 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++;
 		}
 	}
 
-- 
2.40.1