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 <gr...@u256.net>
Cc: sta...@dpdk.org

Signed-off-by: Luc Pelletier <lucp.at.w...@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 b66dfa269b..e65c8a261a 100644
--- a/drivers/net/failsafe/failsafe_ops.c
+++ b/drivers/net/failsafe/failsafe_ops.c
@@ -837,7 +837,7 @@ fs_link_update(struct rte_eth_dev *dev,
                if (likely(sdev_link_ret == 0)) {
                        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

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