-/* the actual enqueue of pointers on the ring.
- * Placed here since identical code needed in both
- * single and multi producer enqueue functions */
-#define ENQUEUE_PTRS(r, ring_start, prod_head, obj_table, n, obj_type) do { \
- unsigned int i; \
- const uint32_t size = (r)->size; \
- uint32_t idx = prod_head & (r)->mask; \
- obj_type *ring = (obj_type *)ring_start; \
- if (likely(idx + n < size)) { \
- for (i = 0; i < (n & ((~(unsigned)0x3))); i+=4, idx+=4) { \
- ring[idx] = obj_table[i]; \
- ring[idx+1] = obj_table[i+1]; \
- ring[idx+2] = obj_table[i+2]; \
- ring[idx+3] = obj_table[i+3]; \
- } \
- switch (n & 0x3) { \
- case 3: \
- ring[idx++] = obj_table[i++]; /* fallthrough */ \
- case 2: \
- ring[idx++] = obj_table[i++]; /* fallthrough */ \
- case 1: \
- ring[idx++] = obj_table[i++]; \
- } \
- } else { \
- for (i = 0; idx < size; i++, idx++)\
- ring[idx] = obj_table[i]; \
- for (idx = 0; i < n; i++, idx++) \
- ring[idx] = obj_table[i]; \
- } \
-} while (0)
-
-/* the actual copy of pointers on the ring to obj_table.
- * Placed here since identical code needed in both
- * single and multi consumer dequeue functions */
-#define DEQUEUE_PTRS(r, ring_start, cons_head, obj_table, n, obj_type) do { \
- unsigned int i; \
- uint32_t idx = cons_head & (r)->mask; \
- const uint32_t size = (r)->size; \
- obj_type *ring = (obj_type *)ring_start; \
- if (likely(idx + n < size)) { \
- for (i = 0; i < (n & (~(unsigned)0x3)); i+=4, idx+=4) {\
- obj_table[i] = ring[idx]; \
- obj_table[i+1] = ring[idx+1]; \
- obj_table[i+2] = ring[idx+2]; \
- obj_table[i+3] = ring[idx+3]; \
- } \
- switch (n & 0x3) { \
- case 3: \
- obj_table[i++] = ring[idx++]; /* fallthrough */ \
- case 2: \
- obj_table[i++] = ring[idx++]; /* fallthrough */ \
- case 1: \
- obj_table[i++] = ring[idx++]; \
- } \
- } else { \
- for (i = 0; idx < size; i++, idx++) \
- obj_table[i] = ring[idx]; \
- for (idx = 0; i < n; i++, idx++) \
- obj_table[i] = ring[idx]; \
- } \
-} while (0)
-
-static __rte_always_inline void
-update_tail(struct rte_ring_headtail *ht, uint32_t old_val, uint32_t new_val,
- uint32_t single)
-{
- /*
- * If there are other enqueues/dequeues in progress that preceded us,
- * we need to wait for them to complete
- */
- if (!single)
- while (unlikely(ht->tail != old_val))
- rte_pause();
-
- ht->tail = new_val;
-}
-
-/**
- * @internal This function updates the producer head for enqueue
- *
- * @param r
- * A pointer to the ring structure
- * @param is_sp
- * Indicates whether multi-producer path is needed or not
- * @param n
- * The number of elements we will want to enqueue, i.e. how far should the
- * head be moved
- * @param behavior
- * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
- * RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible from ring
- * @param old_head
- * Returns head value as it was before the move, i.e. where enqueue starts
- * @param new_head
- * Returns the current/new head value i.e. where enqueue finishes
- * @param free_entries
- * Returns the amount of free space in the ring BEFORE head was moved
- * @return
- * Actual number of objects enqueued.
- * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
- */
-static __rte_always_inline unsigned int
-__rte_ring_move_prod_head(struct rte_ring *r, int is_sp,
- unsigned int n, enum rte_ring_queue_behavior behavior,
- uint32_t *old_head, uint32_t *new_head,
- uint32_t *free_entries)
-{
- const uint32_t mask = r->mask;
- unsigned int max = n;
- int success;
-
- do {
- /* Reset n to the initial burst count */
- n = max;
-
- *old_head = r->prod.head;
- const uint32_t cons_tail = r->cons.tail;
- /* The subtraction is done between two unsigned 32bits value
- * (the result is always modulo 32 bits even if we have
- * *old_head > cons_tail). So 'free_entries' is always between 0
- * and size(ring)-1. */
- *free_entries = (mask + cons_tail - *old_head);
-
- /* check that we have enough room in ring */
- if (unlikely(n > *free_entries))
- n = (behavior == RTE_RING_QUEUE_FIXED) ?
- 0 : *free_entries;
-
- if (n == 0)
- return 0;
-
- *new_head = *old_head + n;
- if (is_sp)
- r->prod.head = *new_head, success = 1;
- else
- success = rte_atomic32_cmpset(&r->prod.head,
- *old_head, *new_head);
- } while (unlikely(success == 0));
- return n;
-}
-
-/**
- * @internal Enqueue several objects on the ring
- *
- * @param r
- * A pointer to the ring structure.
- * @param obj_table
- * A pointer to a table of void * pointers (objects).
- * @param n
- * The number of objects to add in the ring from the obj_table.
- * @param behavior
- * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
- * RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible from ring
- * @param is_sp
- * Indicates whether to use single producer or multi-producer head update
- * @param free_space
- * returns the amount of space after the enqueue operation has finished
- * @return
- * Actual number of objects enqueued.
- * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
- */
-static __rte_always_inline unsigned int
-__rte_ring_do_enqueue(struct rte_ring *r, void * const *obj_table,
- unsigned int n, enum rte_ring_queue_behavior behavior,
- int is_sp, unsigned int *free_space)
-{
- uint32_t prod_head, prod_next;
- uint32_t free_entries;
-
- n = __rte_ring_move_prod_head(r, is_sp, n, behavior,
- &prod_head, &prod_next, &free_entries);
- if (n == 0)
- goto end;
-
- ENQUEUE_PTRS(r, &r[1], prod_head, obj_table, n, void *);
- rte_smp_wmb();
-
- update_tail(&r->prod, prod_head, prod_next, is_sp);
-end:
- if (free_space != NULL)
- *free_space = free_entries - n;
- return n;
-}
-
-/**
- * @internal This function updates the consumer head for dequeue
- *
- * @param r
- * A pointer to the ring structure
- * @param is_sc
- * Indicates whether multi-consumer path is needed or not
- * @param n
- * The number of elements we will want to enqueue, i.e. how far should the
- * head be moved
- * @param behavior
- * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
- * RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from ring
- * @param old_head
- * Returns head value as it was before the move, i.e. where dequeue starts
- * @param new_head
- * Returns the current/new head value i.e. where dequeue finishes
- * @param entries
- * Returns the number of entries in the ring BEFORE head was moved
- * @return
- * - Actual number of objects dequeued.
- * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
- */
-static __rte_always_inline unsigned int
-__rte_ring_move_cons_head(struct rte_ring *r, int is_sc,
- unsigned int n, enum rte_ring_queue_behavior behavior,
- uint32_t *old_head, uint32_t *new_head,
- uint32_t *entries)
-{
- unsigned int max = n;
- int success;
-
- /* move cons.head atomically */
- do {
- /* Restore n as it may change every loop */
- n = max;
-
- *old_head = r->cons.head;
- const uint32_t prod_tail = r->prod.tail;
- /* The subtraction is done between two unsigned 32bits value
- * (the result is always modulo 32 bits even if we have
- * cons_head > prod_tail). So 'entries' is always between 0
- * and size(ring)-1. */
- *entries = (prod_tail - *old_head);
-
- /* Set the actual entries for dequeue */
- if (n > *entries)
- n = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : *entries;
-
- if (unlikely(n == 0))
- return 0;
-
- *new_head = *old_head + n;
- if (is_sc)
- r->cons.head = *new_head, success = 1;
- else
- success = rte_atomic32_cmpset(&r->cons.head, *old_head,
- *new_head);
- } while (unlikely(success == 0));
- return n;
-}
-
-/**
- * @internal Dequeue several objects from the ring
- *
- * @param r
- * A pointer to the ring structure.
- * @param obj_table
- * A pointer to a table of void * pointers (objects).
- * @param n
- * The number of objects to pull from the ring.
- * @param behavior
- * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
- * RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from ring
- * @param is_sc
- * Indicates whether to use single consumer or multi-consumer head update
- * @param available
- * returns the number of remaining ring entries after the dequeue has finished
- * @return
- * - Actual number of objects dequeued.
- * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
- */
-static __rte_always_inline unsigned int
-__rte_ring_do_dequeue(struct rte_ring *r, void **obj_table,
- unsigned int n, enum rte_ring_queue_behavior behavior,
- int is_sc, unsigned int *available)
-{
- uint32_t cons_head, cons_next;
- uint32_t entries;
-
- n = __rte_ring_move_cons_head(r, is_sc, n, behavior,
- &cons_head, &cons_next, &entries);
- if (n == 0)
- goto end;
-
- DEQUEUE_PTRS(r, &r[1], cons_head, obj_table, n, void *);
- rte_smp_rmb();
-
- update_tail(&r->cons, cons_head, cons_next, is_sc);
-
-end:
- if (available != NULL)
- *available = entries - n;
- return n;
-}
-