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From: Luc Pelletier <lucp.at.work@gmail.com>
To: grive@u256.net
Cc: dev@dpdk.org, stephen@networkplumber.org,
	konstantin.ananyev@huawei.com,
	Luc Pelletier <lucp.at.work@gmail.com>,
	stable@dpdk.org
Subject: [PATCH v3 5/5] failsafe: make sub-device remove flag thread-safe
Date: Tue, 29 Nov 2022 09:48:33 -0500	[thread overview]
Message-ID: <20221129144832.2750-6-lucp.at.work@gmail.com> (raw)
In-Reply-To: <20221110163410.12734-1-lucp.at.work@gmail.com>

For each sub-device, there's a remove flag that's used to indicate if
the sub-device has been removed or not. This flag is currently a
volatile bit field. Even if it's marked as volatile, a bit field is not
thread-safe according to the C standard.

The remove flag is now an unsigned int rather than a bit field. We also
now use the atomic built-ins to read/write the value of the remove flag
to ensure thread-safety.

Fixes: 598fb8aec6f6 ("net/failsafe: support device removal")
Cc: Gaetan Rivet <grive@u256.net>
Cc: stable@dpdk.org

Signed-off-by: Luc Pelletier <lucp.at.work@gmail.com>
---
 drivers/net/failsafe/failsafe_ether.c   | 8 ++++----
 drivers/net/failsafe/failsafe_ops.c     | 2 +-
 drivers/net/failsafe/failsafe_private.h | 4 ++--
 drivers/net/failsafe/failsafe_rxtx.c    | 2 +-
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/net/failsafe/failsafe_ether.c b/drivers/net/failsafe/failsafe_ether.c
index 3bfc446638..9014777e52 100644
--- a/drivers/net/failsafe/failsafe_ether.c
+++ b/drivers/net/failsafe/failsafe_ether.c
@@ -311,7 +311,7 @@ fs_dev_remove(struct sub_device *sdev)
 		/* the end */
 		break;
 	}
-	sdev->remove = 0;
+	__atomic_store_n(&sdev->remove, 0, __ATOMIC_RELEASE);
 	failsafe_hotplug_alarm_install(fs_dev(sdev));
 }
 
@@ -388,7 +388,7 @@ failsafe_dev_remove(struct rte_eth_dev *dev)
 	uint8_t i;
 
 	FOREACH_SUBDEV(sdev, i, dev) {
-		if (!sdev->remove)
+		if (!__atomic_load_n(&sdev->remove, __ATOMIC_ACQUIRE))
 			continue;
 
 		/* Active devices must have finished their burst and
@@ -556,7 +556,7 @@ failsafe_eth_dev_state_sync(struct rte_eth_dev *dev)
 err_remove:
 	FOREACH_SUBDEV(sdev, i, dev)
 		if (sdev->state != PRIV(dev)->state)
-			sdev->remove = 1;
+			__atomic_store_n(&sdev->remove, 1, __ATOMIC_RELEASE);
 	return ret;
 }
 
@@ -597,7 +597,7 @@ failsafe_eth_rmv_event_callback(uint16_t port_id __rte_unused,
 	 * Async removal, the sub-PMD will try to unregister
 	 * the callback at the source of the current thread context.
 	 */
-	sdev->remove = 1;
+	__atomic_store_n(&sdev->remove, 1, __ATOMIC_RELEASE);
 	fs_unlock(fs_dev(sdev), 0);
 	return 0;
 }
diff --git a/drivers/net/failsafe/failsafe_ops.c b/drivers/net/failsafe/failsafe_ops.c
index 7bd223af37..86d97970bc 100644
--- a/drivers/net/failsafe/failsafe_ops.c
+++ b/drivers/net/failsafe/failsafe_ops.c
@@ -838,7 +838,7 @@ fs_link_update(struct rte_eth_dev *dev,
 			if (TX_SUBDEV(dev) == sdev)
 				ret = rte_eth_linkstatus_set(dev, &link_info);
 		}
-		else if (sdev->remove == 0 &&
+		else if (__atomic_load_n(&sdev->remove, __ATOMIC_ACQUIRE) == 0 &&
 				rte_eth_dev_is_removed(PORT_ID(sdev)) == 0) {
 			ERROR("Link get failed for sub_device %d with error %d",
 				i, sdev_link_ret);
diff --git a/drivers/net/failsafe/failsafe_private.h b/drivers/net/failsafe/failsafe_private.h
index 3865f2fc34..0577a62ab2 100644
--- a/drivers/net/failsafe/failsafe_private.h
+++ b/drivers/net/failsafe/failsafe_private.h
@@ -131,7 +131,7 @@ struct sub_device {
 	/* sub device port id*/
 	uint16_t sdev_port_id; /* shared between processes */
 	/* flag calling for recollection */
-	volatile unsigned int remove:1;
+	unsigned int remove;
 	/* flow isolation state */
 	int flow_isolated:1;
 	/* RMV callback registration state */
@@ -490,7 +490,7 @@ static inline int
 fs_err(struct sub_device *sdev, int err)
 {
 	/* A device removal shouldn't be reported as an error. */
-	if (sdev->remove == 1 || err == -EIO)
+	if (__atomic_load_n(&sdev->remove, __ATOMIC_ACQUIRE) == 1 || err == -EIO)
 		return rte_errno = 0;
 	return err;
 }
diff --git a/drivers/net/failsafe/failsafe_rxtx.c b/drivers/net/failsafe/failsafe_rxtx.c
index 6d8ab0a6e7..c5caab4204 100644
--- a/drivers/net/failsafe/failsafe_rxtx.c
+++ b/drivers/net/failsafe/failsafe_rxtx.c
@@ -16,7 +16,7 @@ fs_rx_unsafe(struct sub_device *sdev)
 	return (ETH(sdev) == NULL) ||
 		(ETH(sdev)->rx_pkt_burst == NULL) ||
 		(sdev->state != DEV_STARTED) ||
-		(sdev->remove != 0);
+		(__atomic_load_n(&sdev->remove, __ATOMIC_ACQUIRE) != 0);
 }
 
 static inline int
-- 
2.38.1


  parent reply	other threads:[~2022-11-29 14:50 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-10 16:34 [PATCH] failsafe: fix segfault on hotplug event Luc Pelletier
2022-11-10 17:42 ` [PATCH v2] " Luc Pelletier
2022-11-10 23:33   ` Stephen Hemminger
2022-11-16 17:35 ` [PATCH] " Konstantin Ananyev
2022-11-16 21:51   ` Luc Pelletier
2022-11-16 22:25     ` Stephen Hemminger
2022-11-18 16:31       ` Konstantin Ananyev
2022-11-29 14:48 ` [PATCH v3 1/5] " Luc Pelletier
2023-10-31 17:35   ` Stephen Hemminger
2022-11-29 14:48 ` [PATCH v3 3/5] failsafe: fix double release of port Luc Pelletier
2022-11-29 14:48 ` [PATCH v3 4/5] failsafe: use public APIs in fs_link_update Luc Pelletier
2022-11-29 14:48 ` Luc Pelletier [this message]
2022-11-29 15:25 ` [PATCH v4 1/5] failsafe: fix segfault on hotplug event Luc Pelletier
2022-11-29 15:25 ` [PATCH v4 3/5] failsafe: fix double release of port Luc Pelletier
2022-11-29 15:25 ` [PATCH v4 4/5] failsafe: use public APIs in fs_link_update Luc Pelletier
2022-11-29 15:25 ` [PATCH v4 5/5] failsafe: make sub-device remove flag thread-safe Luc Pelletier

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