[dpdk-dev] [PATCH] net/tap: add Rx interrupts

[Moti Haimovsky <motih@mellanox.com>]

This patch adds support for registering and waiting for Rx interrupts.
This allows applications to wait for Rx events from the PMD using the
DPDK rte_epoll subsystem.

Signed-off-by: Moti Haimovsky <motih@mellanox.com>
---
 doc/guides/nics/features/tap.ini |   1 +
 drivers/net/tap/Makefile         |   1 +
 drivers/net/tap/rte_eth_tap.c    |  17 ++++-
 drivers/net/tap/rte_eth_tap.h    |   4 ++
 drivers/net/tap/tap_intr.c       | 147 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 169 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/tap/tap_intr.c

diff --git a/doc/guides/nics/features/tap.ini b/doc/guides/nics/features/tap.ini
index f0e893d..8bc5187 100644
--- a/doc/guides/nics/features/tap.ini
+++ b/doc/guides/nics/features/tap.ini
@@ -7,6 +7,7 @@
 Speed capabilities   = P
 Link status          = Y
 Link status event    = Y
+Rx interrupt         = Y
 Jumbo frame          = Y
 Promiscuous mode     = Y
 Allmulticast mode    = Y
diff --git a/drivers/net/tap/Makefile b/drivers/net/tap/Makefile
index 405b49e..6636b77 100644
--- a/drivers/net/tap/Makefile
+++ b/drivers/net/tap/Makefile
@@ -54,6 +54,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_PMD_TAP) += rte_eth_tap.c
 SRCS-$(CONFIG_RTE_LIBRTE_PMD_TAP) += tap_flow.c
 SRCS-$(CONFIG_RTE_LIBRTE_PMD_TAP) += tap_netlink.c
 SRCS-$(CONFIG_RTE_LIBRTE_PMD_TAP) += tap_tcmsgs.c
+SRCS-$(CONFIG_RTE_LIBRTE_PMD_TAP) += tap_intr.c
 
 include $(RTE_SDK)/mk/rte.lib.mk
 
diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index 6b27679..7e6de68 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -1127,7 +1127,7 @@ enum ioctl_mode {
 }
 
 static int
-tap_intr_handle_set(struct rte_eth_dev *dev, int set)
+tap_lsc_intr_handle_set(struct rte_eth_dev *dev, int set)
 {
 	struct pmd_internals *pmd = dev->data->dev_private;
 
@@ -1152,6 +1152,20 @@ enum ioctl_mode {
 					    tap_dev_intr_handler, dev);
 }
 
+static int
+tap_intr_handle_set(struct rte_eth_dev *dev, int set)
+{
+	int err;
+
+	err = tap_lsc_intr_handle_set(dev, set);
+	if (err)
+		return err;
+	err = tap_rx_intr_vec_set(dev, set);
+	if (err && set)
+		tap_lsc_intr_handle_set(dev, 0);
+	return err;
+}
+
 static const uint32_t*
 tap_dev_supported_ptypes_get(struct rte_eth_dev *dev __rte_unused)
 {
@@ -1284,6 +1298,7 @@ enum ioctl_mode {
 
 	pmd->intr_handle.type = RTE_INTR_HANDLE_EXT;
 	pmd->intr_handle.fd = -1;
+	dev->intr_handle = &pmd->intr_handle;
 
 	/* Presetup the fds to -1 as being not valid */
 	for (i = 0; i < RTE_PMD_TAP_MAX_QUEUES; i++) {
diff --git a/drivers/net/tap/rte_eth_tap.h b/drivers/net/tap/rte_eth_tap.h
index 829f32f..fccc4b8 100644
--- a/drivers/net/tap/rte_eth_tap.h
+++ b/drivers/net/tap/rte_eth_tap.h
@@ -98,4 +98,8 @@ struct pmd_internals {
 	struct rte_intr_handle intr_handle;          /* LSC interrupt handle. */
 };
 
+/* tap_intr.c */
+
+int tap_rx_intr_vec_set(struct rte_eth_dev *dev, int set);
+
 #endif /* _RTE_ETH_TAP_H_ */
diff --git a/drivers/net/tap/tap_intr.c b/drivers/net/tap/tap_intr.c
new file mode 100644
index 0000000..ef25ca6
--- /dev/null
+++ b/drivers/net/tap/tap_intr.c
@@ -0,0 +1,147 @@
+/*-
+ *   BSD LICENSE
+ *
+  *   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 the copyright holder 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.
+ */
+
+/**
+ * @file
+ * Interrupts handling for tap driver.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <rte_eth_tap.h>
+#include <rte_errno.h>
+#include <rte_interrupts.h>
+
+
+/**
+ * Unregister Rx interrupts free the queue interrupt vector.
+ *
+ * @param dev
+ *   Pointer to the tap rte_eth_dev structure.
+ */
+static void
+tap_rx_intr_vec_uninstall(struct rte_eth_dev *dev)
+{
+	struct pmd_internals *pmd = dev->data->dev_private;
+	struct rte_intr_handle *intr_handle = &pmd->intr_handle;
+
+	rte_intr_free_epoll_fd(intr_handle);
+	free(intr_handle->intr_vec);
+	intr_handle->intr_vec = NULL;
+	intr_handle->nb_efd = 0;
+}
+
+/**
+ * Allocate Rx queue interrupt vector and register Rx interrupts.
+ *
+ * @param dev
+ *   Pointer to the tap rte_eth_dev device structure.
+ *
+ * @return
+ *   0 on success, negative errno value otherwise and rte_errno is set.
+ */
+static int
+tap_rx_intr_vec_install(struct rte_eth_dev *dev)
+{
+	struct pmd_internals *pmd = dev->data->dev_private;
+	unsigned int rxqs_n = pmd->dev->data->nb_rx_queues;
+	struct rte_intr_handle *intr_handle = &pmd->intr_handle;
+	unsigned int n = RTE_MIN(rxqs_n, (uint32_t)RTE_MAX_RXTX_INTR_VEC_ID);
+	unsigned int i;
+	unsigned int count = 0;
+
+	if (!dev->data->dev_conf.intr_conf.rxq)
+		return 0;
+	intr_handle->intr_vec = malloc(sizeof(intr_handle->intr_vec[rxqs_n]));
+	if (intr_handle->intr_vec == NULL) {
+		rte_errno = ENOMEM;
+		RTE_LOG(ERR, PMD,
+			"failed to allocate memory for interrupt vector,"
+			" Rx interrupts will not be supported");
+		return -rte_errno;
+	}
+	for (i = 0; i < n; i++) {
+		struct rx_queue *rxq = pmd->dev->data->rx_queues[i];
+
+		/* Skip queues that cannot request interrupts. */
+		if (!rxq || (rxq->fd <= 0)) {
+			/* Use invalid intr_vec[] index to disable entry. */
+			intr_handle->intr_vec[i] =
+				RTE_INTR_VEC_RXTX_OFFSET +
+				RTE_MAX_RXTX_INTR_VEC_ID;
+			continue;
+		}
+		if (count >= RTE_MAX_RXTX_INTR_VEC_ID) {
+			rte_errno = E2BIG;
+			RTE_LOG(ERR, PMD,
+				"too many Rx queues for interrupt vector size"
+				" (%d), Rx interrupts cannot be enabled",
+				RTE_MAX_RXTX_INTR_VEC_ID);
+			tap_rx_intr_vec_uninstall(dev);
+			return -rte_errno;
+		}
+		intr_handle->intr_vec[i] = RTE_INTR_VEC_RXTX_OFFSET + count;
+		intr_handle->efds[count] = rxq->fd;
+		count++;
+	}
+	if (!count)
+		tap_rx_intr_vec_uninstall(dev);
+	else
+		intr_handle->nb_efd = count;
+	return 0;
+}
+
+/**
+ * Register or unregister the Rx interrupts.
+ *
+ * @param dev
+ *   Pointer to the tap rte_eth_dev device structure.
+ * @param set
+ *   should the operation be register or unregister the interrupts.
+ *
+ * @return
+ *   0 on success, negative errno value otherwise and rte_errno is set.
+ */
+int
+tap_rx_intr_vec_set(struct rte_eth_dev *dev, int set)
+{
+	tap_rx_intr_vec_uninstall(dev);
+	if (set)
+		return tap_rx_intr_vec_install(dev);
+	return 0;
+}
-- 
1.8.3.1