net/failsafe: add fail-safe PMD

Introduce the fail-safe poll mode driver initialization and enable its
build infrastructure.

This PMD allows for applications to benefit from true hot-plugging
support without having to implement it.

It intercepts and manages Ethernet device removal events issued by
slave PMDs and re-initializes them transparently when brought back.
It also allows defining a contingency to the removal of a device, by
designating a fail-over device that will take on transmitting operations
if the preferred device is removed.

Applications only see a fail-safe instance, without caring for
underlying activity ensuring their continued operations.

Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
Acked-by: Olga Shern <olgas@mellanox.com>

1 files changed, 138 insertions, 0 deletions

diff --git a/drivers/net/failsafe/failsafe_eal.c b/drivers/net/failsafe/failsafe_eal.c
new file mode 100644
index 0000000..a74edea
--- /dev/null
+++ b/drivers/net/failsafe/failsafe_eal.c
@@ -0,0 +1,138 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright 2017 6WIND S.A.
+ *   Copyright 2017 Mellanox.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of 6WIND S.A. nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <rte_malloc.h>
+
+#include "failsafe_private.h"
+
+static int
+fs_bus_init(struct rte_eth_dev *dev)
+{
+	struct sub_device *sdev;
+	struct rte_devargs *da;
+	uint8_t i;
+	int ret;
+
+	FOREACH_SUBDEV(sdev, i, dev) {
+		if (sdev->state != DEV_PARSED)
+			continue;
+		da = &sdev->devargs;
+		ret = rte_eal_hotplug_add(da->bus->name,
+					  da->name,
+					  da->args);
+		if (ret) {
+			ERROR("sub_device %d probe failed %s%s%s", i,
+			      rte_errno ? "(" : "",
+			      rte_errno ? strerror(rte_errno) : "",
+			      rte_errno ? ")" : "");
+			continue;
+		}
+		ETH(sdev) = rte_eth_dev_allocated(da->name);
+		if (ETH(sdev) == NULL) {
+			ERROR("sub_device %d init went wrong", i);
+			return -ENODEV;
+		}
+		sdev->dev = ETH(sdev)->device;
+		ETH(sdev)->state = RTE_ETH_DEV_DEFERRED;
+		sdev->state = DEV_PROBED;
+	}
+	return 0;
+}
+
+int
+failsafe_eal_init(struct rte_eth_dev *dev)
+{
+	struct sub_device *sdev;
+	uint8_t i;
+	int ret;
+
+	ret = fs_bus_init(dev);
+	if (ret)
+		return ret;
+	/*
+	 * We only update TX_SUBDEV if we are not started.
+	 * If a sub_device is emitting, we will switch the TX_SUBDEV to the
+	 * preferred port only upon starting it, so that the switch is smoother.
+	 */
+	if (PREFERRED_SUBDEV(dev)->state >= DEV_PROBED) {
+		if (TX_SUBDEV(dev) != PREFERRED_SUBDEV(dev) &&
+		    (TX_SUBDEV(dev) == NULL ||
+		     (TX_SUBDEV(dev) && TX_SUBDEV(dev)->state < DEV_STARTED))) {
+			DEBUG("Switching tx_dev to preferred sub_device");
+			PRIV(dev)->subs_tx = 0;
+		}
+	} else {
+		if ((TX_SUBDEV(dev) && TX_SUBDEV(dev)->state < DEV_PROBED) ||
+		    TX_SUBDEV(dev) == NULL) {
+			/* Using first probed device */
+			FOREACH_SUBDEV_STATE(sdev, i, dev, DEV_PROBED) {
+				DEBUG("Switching tx_dev to sub_device %d",
+				      i);
+				PRIV(dev)->subs_tx = i;
+				break;
+			}
+		}
+	}
+	return 0;
+}
+
+static int
+fs_bus_uninit(struct rte_eth_dev *dev)
+{
+	struct sub_device *sdev = NULL;
+	uint8_t i;
+	int ret;
+
+	FOREACH_SUBDEV_STATE(sdev, i, dev, DEV_PROBED) {
+		ret = rte_eal_hotplug_remove(sdev->bus->name,
+					     sdev->dev->name);
+		if (ret) {
+			ERROR("Failed to remove requested device %s",
+			      sdev->dev->name);
+			continue;
+		}
+		sdev->state = DEV_PROBED - 1;
+	}
+	return 0;
+}
+
+int
+failsafe_eal_uninit(struct rte_eth_dev *dev)
+{
+	int ret;
+
+	ret = fs_bus_uninit(dev);
+	if (ret)
+		return ret;
+	return 0;
+}