[PATCH v4 2/9] librte_ether: add new api rte_eth_add_first_rx_callback

[Reshma Pattan <reshma.pattan@intel.com>]

Added new public api rte_eth_add_first_rx_callback to add given
callback as head of list.

Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
---
 lib/librte_ether/rte_ethdev.c          | 35 ++++++++++++++++++++++++++++++++++
 lib/librte_ether/rte_ethdev.h          | 27 ++++++++++++++++++++++++++
 lib/librte_ether/rte_ether_version.map |  6 ++++++
 3 files changed, 68 insertions(+)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index cf25d8a..6331759 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -2959,6 +2959,41 @@ rte_eth_add_rx_callback(uint8_t port_id, uint16_t queue_id,
 }
 
 void *
+rte_eth_add_first_rx_callback(uint8_t port_id, uint16_t queue_id,
+		rte_rx_callback_fn fn, void *user_param)
+{
+#ifndef RTE_ETHDEV_RXTX_CALLBACKS
+	rte_errno = ENOTSUP;
+	return NULL;
+#endif
+	/* check input parameters */
+	if (!rte_eth_dev_is_valid_port(port_id) || fn == NULL ||
+			queue_id >= rte_eth_devices[port_id].data->nb_rx_queues) {
+		rte_errno = EINVAL;
+		return NULL;
+	}
+
+	struct rte_eth_rxtx_callback *cb = rte_zmalloc(NULL, sizeof(*cb), 0);
+
+	if (cb == NULL) {
+		rte_errno = ENOMEM;
+		return NULL;
+	}
+
+	cb->fn.rx = fn;
+	cb->param = user_param;
+
+	rte_spinlock_lock(&rte_eth_rx_cb_lock);
+	/* Add the callbacks at fisrt position*/
+	cb->next = rte_eth_devices[port_id].post_rx_burst_cbs[queue_id];
+	rte_smp_wmb();
+	rte_eth_devices[port_id].post_rx_burst_cbs[queue_id] = cb;
+	rte_spinlock_unlock(&rte_eth_rx_cb_lock);
+
+	return cb;
+}
+
+void *
 rte_eth_add_tx_callback(uint8_t port_id, uint16_t queue_id,
 		rte_tx_callback_fn fn, void *user_param)
 {
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index 2757510..92b07a9 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -3825,6 +3825,33 @@ int rte_eth_dev_get_dcb_info(uint8_t port_id,
 void *rte_eth_add_rx_callback(uint8_t port_id, uint16_t queue_id,
 		rte_rx_callback_fn fn, void *user_param);
 
+/*
+* Add a callback that must be called first on packet RX on a given port and queue.
+*
+* This API configures a first function to be called for each burst of
+* packets received on a given NIC port queue. The return value is a pointer
+* that can be used to later remove the callback using
+* rte_eth_remove_rx_callback().
+*
+* Multiple functions are called in the order that they are added.
+*
+* @param port_id
+*   The port identifier of the Ethernet device.
+* @param queue_id
+*   The queue on the Ethernet device on which the callback is to be added.
+* @param fn
+*   The callback function
+* @param user_param
+*   A generic pointer parameter which will be passed to each invocation of the
+*   callback function on this port and queue.
+*
+* @return
+*   NULL on error.
+*   On success, a pointer value which can later be used to remove the callback.
+*/
+void *rte_eth_add_first_rx_callback(uint8_t port_id, uint16_t queue_id,
+		rte_rx_callback_fn fn, void *user_param);
+
 /**
  * Add a callback to be called on packet TX on a given port and queue.
  *
diff --git a/lib/librte_ether/rte_ether_version.map b/lib/librte_ether/rte_ether_version.map
index 214ecc7..c990b04 100644
--- a/lib/librte_ether/rte_ether_version.map
+++ b/lib/librte_ether/rte_ether_version.map
@@ -132,3 +132,9 @@ DPDK_16.04 {
 	rte_eth_tx_buffer_set_err_callback;
 
 } DPDK_2.2;
+
+DPDK_16.07 {
+	global:
+
+	rte_eth_add_first_rx_callback;
+} DPDK_16.04;
-- 
2.5.0