[dpdk-stable] patch 'net/bnx2x: fix race for periodic flags' has been queued to LTS release 18.11.2

[Kevin Traynor <ktraynor@redhat.com>]

Hi,

FYI, your patch has been queued to LTS release 18.11.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/13/19. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/kevintraynor/dpdk-stable-queue

This queued commit can be viewed at:
https://github.com/kevintraynor/dpdk-stable-queue/commit/c00065cb6d1455933a6d4c1e6362044c9bfa158a

Thanks.

Kevin Traynor

---
From c00065cb6d1455933a6d4c1e6362044c9bfa158a Mon Sep 17 00:00:00 2001
From: Rasesh Mody <rmody@marvell.com>
Date: Thu, 11 Apr 2019 18:47:41 -0700
Subject: [PATCH] net/bnx2x: fix race for periodic flags

[ upstream commit c19eafccb22e1b1ca52439a936908cfd6fd12ff1 ]

The periodic callout function and the interrupt handler both modify the
periodic flags. There is a possible race condition when an application
is going through dev_stop()/dev_start() and an interrupt handler is
invoked. We also need to ensure that periodic polling is not invoked in
interrupt context.

This patch handles such case by using separate variable to check for
interrupt context. Also, atomically load and store the periodic flag
value.

Fixes: 0f6ebeee2402 ("net/bnx2x: fix call to link handling periodic function")

Signed-off-by: Rasesh Mody <rmody@marvell.com>
---
 drivers/net/bnx2x/bnx2x_ethdev.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/net/bnx2x/bnx2x_ethdev.c b/drivers/net/bnx2x/bnx2x_ethdev.c
index fb44a71f2..c628cdc0f 100644
--- a/drivers/net/bnx2x/bnx2x_ethdev.c
+++ b/drivers/net/bnx2x/bnx2x_ethdev.c
@@ -108,5 +108,5 @@ bnx2x_link_update(struct rte_eth_dev *dev)
 
 static void
-bnx2x_interrupt_action(struct rte_eth_dev *dev)
+bnx2x_interrupt_action(struct rte_eth_dev *dev, int intr_cxt)
 {
 	struct bnx2x_softc *sc = dev->data->dev_private;
@@ -115,5 +115,6 @@ bnx2x_interrupt_action(struct rte_eth_dev *dev)
 	bnx2x_intr_legacy(sc);
 
-	if (sc->periodic_flags & PERIODIC_GO)
+	if ((atomic_load_acq_long(&sc->periodic_flags) == PERIODIC_GO) &&
+	    !intr_cxt)
 		bnx2x_periodic_callout(sc);
 	link_status = REG_RD(sc, sc->link_params.shmem_base +
@@ -132,7 +133,5 @@ bnx2x_interrupt_handler(void *param)
 	PMD_DEBUG_PERIODIC_LOG(INFO, sc, "Interrupt handled");
 
-	atomic_store_rel_long(&sc->periodic_flags, PERIODIC_STOP);
-	bnx2x_interrupt_action(dev);
-	atomic_store_rel_long(&sc->periodic_flags, PERIODIC_GO);
+	bnx2x_interrupt_action(dev, 1);
 	rte_intr_enable(&sc->pci_dev->intr_handle);
 }
@@ -145,5 +144,5 @@ static void bnx2x_periodic_start(void *param)
 
 	atomic_store_rel_long(&sc->periodic_flags, PERIODIC_GO);
-	bnx2x_interrupt_action(dev);
+	bnx2x_interrupt_action(dev, 0);
 	if (IS_PF(sc)) {
 		ret = rte_eal_alarm_set(BNX2X_SP_TIMER_PERIOD,
@@ -165,4 +164,6 @@ void bnx2x_periodic_stop(void *param)
 
 	rte_eal_alarm_cancel(bnx2x_periodic_start, (void *)dev);
+
+	PMD_DRV_LOG(DEBUG, sc, "Periodic poll stopped");
 }
 
@@ -226,6 +227,8 @@ bnx2x_dev_start(struct rte_eth_dev *dev)
 
 	/* start the periodic callout */
-	if (sc->periodic_flags & PERIODIC_STOP)
+	if (atomic_load_acq_long(&sc->periodic_flags) == PERIODIC_STOP) {
 		bnx2x_periodic_start(dev);
+		PMD_DRV_LOG(DEBUG, sc, "Periodic poll re-started");
+	}
 
 	ret = bnx2x_init(sc);
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2019-05-08 11:05:06.113850223 +0100
+++ 0005-net-bnx2x-fix-race-for-periodic-flags.patch	2019-05-08 11:05:05.752934373 +0100
@@ -1 +1 @@
-From c19eafccb22e1b1ca52439a936908cfd6fd12ff1 Mon Sep 17 00:00:00 2001
+From c00065cb6d1455933a6d4c1e6362044c9bfa158a Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit c19eafccb22e1b1ca52439a936908cfd6fd12ff1 ]
+
@@ -17 +18,0 @@
-Cc: stable@dpdk.org
@@ -25 +26 @@
-index f85766c68..3063aea64 100644
+index fb44a71f2..c628cdc0f 100644
@@ -28 +29 @@
-@@ -109,5 +109,5 @@ bnx2x_link_update(struct rte_eth_dev *dev)
+@@ -108,5 +108,5 @@ bnx2x_link_update(struct rte_eth_dev *dev)
@@ -35 +36 @@
-@@ -116,5 +116,6 @@ bnx2x_interrupt_action(struct rte_eth_dev *dev)
+@@ -115,5 +115,6 @@ bnx2x_interrupt_action(struct rte_eth_dev *dev)
@@ -43 +44 @@
-@@ -133,7 +134,5 @@ bnx2x_interrupt_handler(void *param)
+@@ -132,7 +133,5 @@ bnx2x_interrupt_handler(void *param)
@@ -52 +53 @@
-@@ -146,5 +145,5 @@ static void bnx2x_periodic_start(void *param)
+@@ -145,5 +144,5 @@ static void bnx2x_periodic_start(void *param)
@@ -59 +60 @@
-@@ -166,4 +165,6 @@ void bnx2x_periodic_stop(void *param)
+@@ -165,4 +164,6 @@ void bnx2x_periodic_stop(void *param)
@@ -66 +67 @@
-@@ -227,6 +228,8 @@ bnx2x_dev_start(struct rte_eth_dev *dev)
+@@ -226,6 +227,8 @@ bnx2x_dev_start(struct rte_eth_dev *dev)