ring: support configurable element size

Current APIs assume ring elements to be pointers. However, in many
use cases, the size can be different. Add new APIs to support
configurable ring element sizes.

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>

lib/librte_ring/Makefile

@@ -6,7 +6,7 @@ include $(RTE_SDK)/mk/rte.vars.mk
 # library name
 LIB = librte_ring.a
 
-CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3
+CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -DALLOW_EXPERIMENTAL_API
 LDLIBS += -lrte_eal
 
 EXPORT_MAP := rte_ring_version.map
@@ -16,6 +16,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_RING) := rte_ring.c
 
 # install includes
 SYMLINK-$(CONFIG_RTE_LIBRTE_RING)-include := rte_ring.h \
+					rte_ring_elem.h \
 					rte_ring_generic.h \
 					rte_ring_c11_mem.h
 

lib/librte_ring/meson.build

@@ -3,5 +3,9 @@
 
 sources = files('rte_ring.c')
 headers = files('rte_ring.h',
+		'rte_ring_elem.h',
 		'rte_ring_c11_mem.h',
 		'rte_ring_generic.h')
+
+# rte_ring_create_elem and rte_ring_get_memsize_elem are experimental
+allow_experimental_apis = true

lib/librte_ring/rte_ring.c

@@ -33,6 +33,7 @@
 #include <rte_tailq.h>
 
 #include "rte_ring.h"
+#include "rte_ring_elem.h"
 
 TAILQ_HEAD(rte_ring_list, rte_tailq_entry);
 
@@ -46,23 +47,38 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
 
 /* return the size of memory occupied by a ring */
 ssize_t
-rte_ring_get_memsize(unsigned count)
+rte_ring_get_memsize_elem(unsigned int esize, unsigned int count)
 {
 	ssize_t sz;
 
+	/* Check if element size is a multiple of 4B */
+	if (esize % 4 != 0) {
+		RTE_LOG(ERR, RING, "element size is not a multiple of 4\n");
+
+		return -EINVAL;
+	}
+
 	/* count must be a power of 2 */
 	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
 		RTE_LOG(ERR, RING,
-			"Requested size is invalid, must be power of 2, and "
-			"do not exceed the size limit %u\n", RTE_RING_SZ_MASK);
+			"Requested number of elements is invalid, must be power of 2, and not exceed %u\n",
+			RTE_RING_SZ_MASK);
+
 		return -EINVAL;
 	}
 
-	sz = sizeof(struct rte_ring) + count * sizeof(void *);
+	sz = sizeof(struct rte_ring) + count * esize;
 	sz = RTE_ALIGN(sz, RTE_CACHE_LINE_SIZE);
 	return sz;
 }
 
+/* return the size of memory occupied by a ring */
+ssize_t
+rte_ring_get_memsize(unsigned int count)
+{
+	return rte_ring_get_memsize_elem(sizeof(void *), count);
+}
+
 void
 rte_ring_reset(struct rte_ring *r)
 {
@@ -114,10 +130,10 @@ rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
 	return 0;
 }
 
-/* create the ring */
+/* create the ring for a given element size */
 struct rte_ring *
-rte_ring_create(const char *name, unsigned count, int socket_id,
-		unsigned flags)
+rte_ring_create_elem(const char *name, unsigned int esize, unsigned int count,
+		int socket_id, unsigned int flags)
 {
 	char mz_name[RTE_MEMZONE_NAMESIZE];
 	struct rte_ring *r;
@@ -135,7 +151,7 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 	if (flags & RING_F_EXACT_SZ)
 		count = rte_align32pow2(count + 1);
 
-	ring_size = rte_ring_get_memsize(count);
+	ring_size = rte_ring_get_memsize_elem(esize, count);
 	if (ring_size < 0) {
 		rte_errno = ring_size;
 		return NULL;
@@ -182,6 +198,15 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 	return r;
 }
 
+/* create the ring */
+struct rte_ring *
+rte_ring_create(const char *name, unsigned int count, int socket_id,
+		unsigned int flags)
+{
+	return rte_ring_create_elem(name, sizeof(void *), count, socket_id,
+		flags);
+}
+
 /* free the ring */
 void
 rte_ring_free(struct rte_ring *r)

lib/librte_ring/rte_ring.h

@@ -216,6 +216,7 @@ 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.
  *

lib/librte_ring/rte_ring_version.map

@@ -15,6 +15,10 @@ DPDK_20.0 {
 EXPERIMENTAL {
 	global:
 
+	# added in 19.08
 	rte_ring_reset;
 
+	# added in 20.02
+	rte_ring_create_elem;
+	rte_ring_get_memsize_elem;
 };