[dpdk-dev] [PATCH v3] ring: add function to free a ring

[Pablo de Lara]

From: "Pablo de Lara" <pablo.de.lara.guarch at intel.com>

When creating a ring, a memzone is created to allocate it in memory,
but the ring could not be freed, as memzones could not be.

Since memzones can be freed now, then rings can be as well,
taking into account if they were initialized using pre-allocated memory
(in which case, memory should be freed externally) or using rte_memzone_reserve
(with rte_ring_create), freeing the memory with rte_memzone_free.

Signed-off-by: Pablo de Lara <pablo.de.lara.guarch at intel.com>
---
Changes in v3:
 - Simplify patch using stored memzone address in ring structure
 - Change copyright date

Changes in v2:
 - Include note in release notes
 - Add error log when ring cannot be freed

This patch depends on patch "rte_ring: store memzone pointer inside ring"

 doc/guides/rel_notes/release_2_2.rst |  4 +++
 lib/librte_ring/rte_ring.c           | 47 +++++++++++++++++++++++++++++++++++-
 lib/librte_ring/rte_ring.h           |  7 ++++++
 lib/librte_ring/rte_ring_version.map |  7 ++++++
 4 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/doc/guides/rel_notes/release_2_2.rst b/doc/guides/rel_notes/release_2_2.rst
index 5687676..24937ac 100644
--- a/doc/guides/rel_notes/release_2_2.rst
+++ b/doc/guides/rel_notes/release_2_2.rst
@@ -4,6 +4,10 @@ DPDK Release 2.2
 New Features
 ------------
 
+* **Enabled freeing of rte_ring.**
+
+  New function rte_ring_free() allows the user to free a ring
+  if it was created with rte_ring_create().
 
 Resolved Issues
 ---------------
diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
index 4e78e14..d80faf3 100644
--- a/lib/librte_ring/rte_ring.c
+++ b/lib/librte_ring/rte_ring.c
@@ -1,7 +1,7 @@
 /*-
  *   BSD LICENSE
  *
- *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
  *   All rights reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
@@ -209,6 +209,51 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 	return r;
 }
 
+/* free the ring */
+void
+rte_ring_free(struct rte_ring *r)
+{
+	struct rte_ring_list *ring_list = NULL;
+	struct rte_tailq_entry *te;
+
+	if (r == NULL)
+		return;
+
+	/*
+	 * Ring was not created with rte_ring_create,
+	 * therefore, there is no memzone to free.
+	 */
+	if (r->memzone == NULL) {
+		RTE_LOG(ERR, RING, "Cannot free ring (not created with rte_ring_create()");
+		return;
+	}
+
+	if (rte_memzone_free(r->memzone) != 0) {
+		RTE_LOG(ERR, RING, "Cannot free memory\n");
+		return;
+	}
+
+	ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);
+	rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
+
+	/* find out tailq entry */
+	TAILQ_FOREACH(te, ring_list, next) {
+		if (te->data == (void *) r)
+			break;
+	}
+
+	if (te == NULL) {
+		rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
+		return;
+	}
+
+	TAILQ_REMOVE(ring_list, te, next);
+
+	rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
+
+	rte_free(te);
+}
+
 /*
  * change the high water mark. If *count* is 0, water marking is
  * disabled
diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index df45f3f..fb5a626 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -304,6 +304,13 @@ int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
  */
 struct rte_ring *rte_ring_create(const char *name, unsigned count,
 				 int socket_id, unsigned flags);
+/**
+ * De-allocate all memory used by the ring.
+ *
+ * @param r
+ *   Ring to free
+ */
+void rte_ring_free(struct rte_ring *r);
 
 /**
  * Change the high water mark.
diff --git a/lib/librte_ring/rte_ring_version.map b/lib/librte_ring/rte_ring_version.map
index 982fdd1..5474b98 100644
--- a/lib/librte_ring/rte_ring_version.map
+++ b/lib/librte_ring/rte_ring_version.map
@@ -11,3 +11,10 @@ DPDK_2.0 {
 
 	local: *;
 };
+
+DPDK_2.2 {
+	global:
+
+	rte_ring_free;
+
+} DPDK_2.0;
-- 
2.4.3