[PATCH 04/10] kni: add rte_kni_free to KNI library

[PATCH 04/10] kni: add rte_kni_free to KNI library

[Dan Gora]

Add the new rte_kni_free() API function to the KNI library.

This function will be called by DPDK applications after
rte_kni_release() to free the KNI interface resources from the
kernel driver.

Signed-off-by: Dan Gora <dg@adax.com>
---
 lib/librte_kni/rte_kni.c | 32 +++++++++++++++++++++++++++++---
 lib/librte_kni/rte_kni.h | 31 +++++++++++++++++++++++++++----
 2 files changed, 56 insertions(+), 7 deletions(-)

diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
index 8a8f6c1cc..1d84c0b70 100644
--- a/lib/librte_kni/rte_kni.c
+++ b/lib/librte_kni/rte_kni.c
@@ -463,8 +463,6 @@ int
 rte_kni_release(struct rte_kni *kni)
 {
 	struct rte_kni_device_info dev_info;
-	uint32_t slot_id;
-	uint32_t retry = 5;
 
 	if (!kni || !kni->in_use)
 		return -1;
@@ -475,6 +473,34 @@ rte_kni_release(struct rte_kni *kni)
 		return -1;
 	}
 
+	kni->in_use = 0;
+	return 0;
+}
+
+int
+rte_kni_free(struct rte_kni *kni)
+{
+	uint32_t slot_id;
+	uint32_t retry = 5;
+	struct rte_kni_device_info dev_info;
+
+	if (!kni)
+		return -EINVAL;
+
+	/* Must call rte_kni_release() first */
+	if (kni->in_use)
+		return -EBUSY;
+
+	/*
+	 * Free the FIFOs in the kernel and remove it from the list
+	 * of devices to poll
+	 */
+	snprintf(dev_info.name, sizeof(dev_info.name), "%s", kni->name);
+	if (ioctl(kni_fd, RTE_KNI_IOCTL_FREE, &dev_info) < 0) {
+		RTE_LOG(ERR, KNI, "Fail to release kni device\n");
+		return -1;
+	}
+
 	/* mbufs in all fifo should be released, except request/response */
 
 	/* wait until all rxq packets processed by kernel */
@@ -497,7 +523,7 @@ rte_kni_release(struct rte_kni *kni)
 	if (slot_id > kni_memzone_pool.max_ifaces) {
 		RTE_LOG(ERR, KNI, "KNI pool: corrupted slot ID: %d, max: %d\n",
 			slot_id, kni_memzone_pool.max_ifaces);
-		return -1;
+		return -EINVAL;
 	}
 	kni_memzone_pool_release(&kni_memzone_pool.slots[slot_id]);
 
diff --git a/lib/librte_kni/rte_kni.h b/lib/librte_kni/rte_kni.h
index 99055e2c2..d1a95f898 100644
--- a/lib/librte_kni/rte_kni.h
+++ b/lib/librte_kni/rte_kni.h
@@ -112,11 +112,17 @@ struct rte_kni *rte_kni_alloc(struct rte_mempool *pktmbuf_pool,
 		const struct rte_kni_conf *conf, struct rte_kni_ops *ops);
 
 /**
- * Release KNI interface according to the context. It will also release the
- * paired KNI interface in kernel space. All processing on the specific KNI
- * context need to be stopped before calling this interface.
+ * Release specified KNI interface. This will stop data transfer to and from
+ * this interface and will remove the paired KNI interface in kernel space.
  *
- * rte_kni_release is thread safe.
+ * @note This function will trigger the kernel to remove the interface, which
+ * may trigger the RTE_KNI_REQ_CFG_NETWORK_IF KNI callback. This function will
+ * block until this callback is handled or times out. The user should ensure
+ * that rte_kni_handle_request() is called for this interface in a separate
+ * thread to handle this callback to avoid this delay.
+ *
+ * rte_kni_release() is thread safe, but should not be called from the same
+ * thread as rte_kni_handle_request().
  *
  * @param kni
  *  The pointer to the context of an existent KNI interface.
@@ -127,6 +133,23 @@ struct rte_kni *rte_kni_alloc(struct rte_mempool *pktmbuf_pool,
  */
 int rte_kni_release(struct rte_kni *kni);
 
+/**
+ * Free specified KNI interface. It will also free the KNI interface resources
+ * in kernel space. No KNI functions for this interface should be called after
+ * or at the same time as calling this function. rte_kni_release() must be
+ * called before this function to release the kernel interface.
+ *
+ * @param kni
+ *  The pointer to the context of an existent KNI interface.
+ *
+ * @return
+ *  - 0 indicates success.
+ *  - -EINVAL: Invalid kni structure.
+ *  - -EBUSY: KNI interface still in use.  Must call rte_kni_release().
+ */
+int __rte_experimental
+rte_kni_free(struct rte_kni *kni);
+
 /**
  * It is used to handle the request mbufs sent from kernel space.
  * Then analyzes it and calls the specific actions for the specific requests.
-- 
2.18.0.rc1.1.g6f333ff2f