lib: use C99 syntax for zero-size arrays

[dpdk.git] / lib / librte_ring / rte_ring.h

diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index af68888..dfe07a2 100644 (file)
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -100,6 +100,7 @@ extern "C" {
 #include <rte_lcore.h>
 #include <rte_atomic.h>
 #include <rte_branch_prediction.h>
+#include <rte_memzone.h>
 
 #define RTE_TAILQ_RING_NAME "RTE_RING"
 
@@ -126,14 +127,18 @@ struct rte_ring_debug_stats {
 } __rte_cache_aligned;
 #endif
 
-#define RTE_RING_NAMESIZE 32 /**< The maximum length of a ring name. */
 #define RTE_RING_MZ_PREFIX "RG_"
+/**< The maximum length of a ring name. */
+#define RTE_RING_NAMESIZE (RTE_MEMZONE_NAMESIZE - \
+                          sizeof(RTE_RING_MZ_PREFIX) + 1)
 
 #ifndef RTE_RING_PAUSE_REP_COUNT
 #define RTE_RING_PAUSE_REP_COUNT 0 /**< Yield after pause num of times, no yield
                                     *   if RTE_RING_PAUSE_REP not defined. */
 #endif
 
+struct rte_memzone; /* forward declaration, so as not to require memzone.h */
+
 /**
  * An RTE ring structure.
  *
@@ -145,8 +150,15 @@ struct rte_ring_debug_stats {
  * a problem.
  */
 struct rte_ring {
-       char name[RTE_RING_NAMESIZE];    /**< Name of the ring. */
+       /*
+        * Note: this field kept the RTE_MEMZONE_NAMESIZE size due to ABI
+        * compatibility requirements, it could be changed to RTE_RING_NAMESIZE
+        * next time the ABI changes
+        */
+       char name[RTE_MEMZONE_NAMESIZE];    /**< Name of the ring. */
        int flags;                       /**< Flags supplied at creation. */
+       const struct rte_memzone *memzone;
+                       /**< Memzone, if any, containing the rte_ring */
 
        /** Ring producer status. */
        struct prod {
@@ -175,7 +187,7 @@ struct rte_ring {
        struct rte_ring_debug_stats stats[RTE_MAX_LCORE];
 #endif
 
-       void * ring[0] __rte_cache_aligned; /**< Memory space of ring starts here.
+       void *ring[] __rte_cache_aligned;   /**< Memory space of ring starts here.
                                             * not volatile so need to be careful
                                             * about compiler re-ordering */
 };
@@ -300,6 +312,13 @@ 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.
@@ -420,6 +439,11 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
        uint32_t mask = r->prod.mask;
        int ret;
 
+       /* Avoid the unnecessary cmpset operation below, which is also
+        * potentially harmful when n equals 0. */
+       if (n == 0)
+               return 0;
+
        /* move prod.head atomically */
        do {
                /* Reset n to the initial burst count */
@@ -457,7 +481,7 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
 
        /* write entries in ring */
        ENQUEUE_PTRS();
-       rte_compiler_barrier();
+       rte_smp_wmb();
 
        /* if we exceed the watermark */
        if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
@@ -552,7 +576,7 @@ __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
 
        /* write entries in ring */
        ENQUEUE_PTRS();
-       rte_compiler_barrier();
+       rte_smp_wmb();
 
        /* if we exceed the watermark */
        if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
@@ -607,6 +631,11 @@ __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
        unsigned i, rep = 0;
        uint32_t mask = r->prod.mask;
 
+       /* Avoid the unnecessary cmpset operation below, which is also
+        * potentially harmful when n equals 0. */
+       if (n == 0)
+               return 0;
+
        /* move cons.head atomically */
        do {
                /* Restore n as it may change every loop */
@@ -643,7 +672,7 @@ __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
 
        /* copy in table */
        DEQUEUE_PTRS();
-       rte_compiler_barrier();
+       rte_smp_rmb();
 
        /*
         * If there are other dequeues in progress that preceded us,
@@ -727,7 +756,7 @@ __rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
 
        /* copy in table */
        DEQUEUE_PTRS();
-       rte_compiler_barrier();
+       rte_smp_rmb();
 
        __RING_STAT_ADD(r, deq_success, n);
        r->cons.tail = cons_next;
@@ -1026,7 +1055,7 @@ rte_ring_full(const struct rte_ring *r)
 {
        uint32_t prod_tail = r->prod.tail;
        uint32_t cons_tail = r->cons.tail;
-       return (((cons_tail - prod_tail - 1) & r->prod.mask) == 0);
+       return ((cons_tail - prod_tail - 1) & r->prod.mask) == 0;
 }
 
 /**
@@ -1059,7 +1088,7 @@ rte_ring_count(const struct rte_ring *r)
 {
        uint32_t prod_tail = r->prod.tail;
        uint32_t cons_tail = r->cons.tail;
-       return ((prod_tail - cons_tail) & r->prod.mask);
+       return (prod_tail - cons_tail) & r->prod.mask;
 }
 
 /**
@@ -1075,7 +1104,7 @@ rte_ring_free_count(const struct rte_ring *r)
 {
        uint32_t prod_tail = r->prod.tail;
        uint32_t cons_tail = r->cons.tail;
-       return ((cons_tail - prod_tail - 1) & r->prod.mask);
+       return (cons_tail - prod_tail - 1) & r->prod.mask;
 }
 
 /**