1 files changed, 284 insertions, 0 deletions
diff --git a/drivers/infiniband/sw/rxe/rxe_queue.h b/drivers/infiniband/sw/rxe/rxe_queue.h
new file mode 100644
index 000000000..c711cb98b
--- /dev/null
+++ b/drivers/infiniband/sw/rxe/rxe_queue.h
@@ -0,0 +1,284 @@
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/*
+ * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
+ * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
+ */
+
+#ifndef RXE_QUEUE_H
+#define RXE_QUEUE_H
+
+/* Implements a simple circular buffer that is shared between user
+ * and the driver and can be resized. The requested element size is
+ * rounded up to a power of 2 and the number of elements in the buffer
+ * is also rounded up to a power of 2. Since the queue is empty when
+ * the producer and consumer indices match the maximum capacity of the
+ * queue is one less than the number of element slots.
+ *
+ * Notes:
+ *   - The driver indices are always masked off to q->index_mask
+ *     before storing so do not need to be checked on reads.
+ *   - The user whether user space or kernel is generally
+ *     not trusted so its parameters are masked to make sure
+ *     they do not access the queue out of bounds on reads.
+ *   - The driver indices for queues must not be written
+ *     by user so a local copy is used and a shared copy is
+ *     stored when the local copy is changed.
+ *   - By passing the type in the parameter list separate from q
+ *     the compiler can eliminate the switch statement when the
+ *     actual queue type is known when the function is called at
+ *     compile time.
+ *   - These queues are lock free. The user and driver must protect
+ *     changes to their end of the queues with locks if more than one
+ *     CPU can be accessing it at the same time.
+ */
+
+/**
+ * enum queue_type - type of queue
+ * @QUEUE_TYPE_TO_CLIENT:	Queue is written by rxe driver and
+ *				read by client which may be a user space
+ *				application or a kernel ulp.
+ *				Used by rxe internals only.
+ * @QUEUE_TYPE_FROM_CLIENT:	Queue is written by client and
+ *				read by rxe driver.
+ *				Used by rxe internals only.
+ * @QUEUE_TYPE_FROM_ULP:	Queue is written by kernel ulp and
+ *				read by rxe driver.
+ *				Used by kernel verbs APIs only on
+ *				behalf of ulps.
+ * @QUEUE_TYPE_TO_ULP:		Queue is written by rxe driver and
+ *				read by kernel ulp.
+ *				Used by kernel verbs APIs only on
+ *				behalf of ulps.
+ */
+enum queue_type {
+	QUEUE_TYPE_TO_CLIENT,
+	QUEUE_TYPE_FROM_CLIENT,
+	QUEUE_TYPE_FROM_ULP,
+	QUEUE_TYPE_TO_ULP,
+};
+
+struct rxe_queue_buf;
+
+struct rxe_queue {
+	struct rxe_dev		*rxe;
+	struct rxe_queue_buf	*buf;
+	struct rxe_mmap_info	*ip;
+	size_t			buf_size;
+	size_t			elem_size;
+	unsigned int		log2_elem_size;
+	u32			index_mask;
+	enum queue_type		type;
+	/* private copy of index for shared queues between
+	 * driver and clients. Driver reads and writes
+	 * this copy and then replicates to rxe_queue_buf
+	 * for read access by clients.
+	 */
+	u32			index;
+};
+
+int do_mmap_info(struct rxe_dev *rxe, struct mminfo __user *outbuf,
+		 struct ib_udata *udata, struct rxe_queue_buf *buf,
+		 size_t buf_size, struct rxe_mmap_info **ip_p);
+
+void rxe_queue_reset(struct rxe_queue *q);
+
+struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe, int *num_elem,
+			unsigned int elem_size, enum queue_type type);
+
+int rxe_queue_resize(struct rxe_queue *q, unsigned int *num_elem_p,
+		     unsigned int elem_size, struct ib_udata *udata,
+		     struct mminfo __user *outbuf,
+		     spinlock_t *producer_lock, spinlock_t *consumer_lock);
+
+void rxe_queue_cleanup(struct rxe_queue *queue);
+
+static inline u32 queue_next_index(struct rxe_queue *q, int index)
+{
+	return (index + 1) & q->index_mask;
+}
+
+static inline u32 queue_get_producer(const struct rxe_queue *q,
+				     enum queue_type type)
+{
+	u32 prod;
+
+	switch (type) {
+	case QUEUE_TYPE_FROM_CLIENT:
+		/* used by rxe, client owns the index */
+		prod = smp_load_acquire(&q->buf->producer_index);
+		break;
+	case QUEUE_TYPE_TO_CLIENT:
+		/* used by rxe which owns the index */
+		prod = q->index;
+		break;
+	case QUEUE_TYPE_FROM_ULP:
+		/* used by ulp which owns the index */
+		prod = q->buf->producer_index;
+		break;
+	case QUEUE_TYPE_TO_ULP:
+		/* used by ulp, rxe owns the index */
+		prod = smp_load_acquire(&q->buf->producer_index);
+		break;
+	}
+
+	return prod;
+}
+
+static inline u32 queue_get_consumer(const struct rxe_queue *q,
+				     enum queue_type type)
+{
+	u32 cons;
+
+	switch (type) {
+	case QUEUE_TYPE_FROM_CLIENT:
+		/* used by rxe which owns the index */
+		cons = q->index;
+		break;
+	case QUEUE_TYPE_TO_CLIENT:
+		/* used by rxe, client owns the index */
+		cons = smp_load_acquire(&q->buf->consumer_index);
+		break;
+	case QUEUE_TYPE_FROM_ULP:
+		/* used by ulp, rxe owns the index */
+		cons = smp_load_acquire(&q->buf->consumer_index);
+		break;
+	case QUEUE_TYPE_TO_ULP:
+		/* used by ulp which owns the index */
+		cons = q->buf->consumer_index;
+		break;
+	}
+
+	return cons;
+}
+
+static inline int queue_empty(struct rxe_queue *q, enum queue_type type)
+{
+	u32 prod = queue_get_producer(q, type);
+	u32 cons = queue_get_consumer(q, type);
+
+	return ((prod - cons) & q->index_mask) == 0;
+}
+
+static inline int queue_full(struct rxe_queue *q, enum queue_type type)
+{
+	u32 prod = queue_get_producer(q, type);
+	u32 cons = queue_get_consumer(q, type);
+
+	return ((prod + 1 - cons) & q->index_mask) == 0;
+}
+
+static inline u32 queue_count(const struct rxe_queue *q,
+					enum queue_type type)
+{
+	u32 prod = queue_get_producer(q, type);
+	u32 cons = queue_get_consumer(q, type);
+
+	return (prod - cons) & q->index_mask;
+}
+
+static inline void queue_advance_producer(struct rxe_queue *q,
+					  enum queue_type type)
+{
+	u32 prod;
+
+	switch (type) {
+	case QUEUE_TYPE_FROM_CLIENT:
+		/* used by rxe, client owns the index */
+		if (WARN_ON(1))
+			pr_warn("%s: attempt to advance client index\n",
+				__func__);
+		break;
+	case QUEUE_TYPE_TO_CLIENT:
+		/* used by rxe which owns the index */
+		prod = q->index;
+		prod = (prod + 1) & q->index_mask;
+		q->index = prod;
+		/* release so client can read it safely */
+		smp_store_release(&q->buf->producer_index, prod);
+		break;
+	case QUEUE_TYPE_FROM_ULP:
+		/* used by ulp which owns the index */
+		prod = q->buf->producer_index;
+		prod = (prod + 1) & q->index_mask;
+		/* release so rxe can read it safely */
+		smp_store_release(&q->buf->producer_index, prod);
+		break;
+	case QUEUE_TYPE_TO_ULP:
+		/* used by ulp, rxe owns the index */
+		if (WARN_ON(1))
+			pr_warn("%s: attempt to advance driver index\n",
+				__func__);
+		break;
+	}
+}
+
+static inline void queue_advance_consumer(struct rxe_queue *q,
+					  enum queue_type type)
+{
+	u32 cons;
+
+	switch (type) {
+	case QUEUE_TYPE_FROM_CLIENT:
+		/* used by rxe which owns the index */
+		cons = (q->index + 1) & q->index_mask;
+		q->index = cons;
+		/* release so client can read it safely */
+		smp_store_release(&q->buf->consumer_index, cons);
+		break;
+	case QUEUE_TYPE_TO_CLIENT:
+		/* used by rxe, client owns the index */
+		if (WARN_ON(1))
+			pr_warn("%s: attempt to advance client index\n",
+				__func__);
+		break;
+	case QUEUE_TYPE_FROM_ULP:
+		/* used by ulp, rxe owns the index */
+		if (WARN_ON(1))
+			pr_warn("%s: attempt to advance driver index\n",
+				__func__);
+		break;
+	case QUEUE_TYPE_TO_ULP:
+		/* used by ulp which owns the index */
+		cons = q->buf->consumer_index;
+		cons = (cons + 1) & q->index_mask;
+		/* release so rxe can read it safely */
+		smp_store_release(&q->buf->consumer_index, cons);
+		break;
+	}
+}
+
+static inline void *queue_producer_addr(struct rxe_queue *q,
+					enum queue_type type)
+{
+	u32 prod = queue_get_producer(q, type);
+
+	return q->buf->data + (prod << q->log2_elem_size);
+}
+
+static inline void *queue_consumer_addr(struct rxe_queue *q,
+					enum queue_type type)
+{
+	u32 cons = queue_get_consumer(q, type);
+
+	return q->buf->data + (cons << q->log2_elem_size);
+}
+
+static inline void *queue_addr_from_index(struct rxe_queue *q, u32 index)
+{
+	return q->buf->data + ((index & q->index_mask)
+				<< q->log2_elem_size);
+}
+
+static inline u32 queue_index_from_addr(const struct rxe_queue *q,
+				const void *addr)
+{
+	return (((u8 *)addr - q->buf->data) >> q->log2_elem_size)
+				& q->index_mask;
+}
+
+static inline void *queue_head(struct rxe_queue *q, enum queue_type type)
+{
+	return queue_empty(q, type) ? NULL : queue_consumer_addr(q, type);
+}
+
+#endif /* RXE_QUEUE_H */