IB/core: Introduce Work Queue object and its verbs

Introduce Work Queue object and its create/destroy/modify verbs.

QP can be created without internal WQs "packaged" inside it,
this QP can be configured to use "external" WQ object as its
receive/send queue.
WQ is a necessary component for RSS technology since RSS mechanism
is supposed to distribute the traffic between multiple
Receive Work Queues.

WQ associated (many to one) with Completion Queue and it owns WQ
properties (PD, WQ size, etc.).
WQ has a type, this patch introduces the IB_WQT_RQ (i.e.receive queue),
it may be extend to others such as IB_WQT_SQ. (send queue).
WQ from type IB_WQT_RQ contains receive work requests.

PD is an attribute of a work queue (i.e. send/receive queue), it's used
by the hardware for security validation before scattering to a memory
region which is pointed by the WQ. For that, an external WQ object
needs a PD, letting the hardware makes that validation.

When accessing a memory region that is pointed by the WQ its PD
is used and not the QP's PD, this behavior is similar
to a SRQ and a QP.

WQ context is subject to a well-defined state transitions done by
the modify_wq verb.
When WQ is created its initial state becomes IB_WQS_RESET.
>From IB_WQS_RESET it can be modified to itself or to IB_WQS_RDY.
>From IB_WQS_RDY it can be modified to itself, to IB_WQS_RESET
or to IB_WQS_ERR.
>From IB_WQS_ERR it can be modified to IB_WQS_RESET.

Note: transition to IB_WQS_ERR might occur implicitly in case there
was some HW error.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/verbs.c

@@ -1554,6 +1554,88 @@ int ib_dealloc_xrcd(struct ib_xrcd *xrcd)
 }
 EXPORT_SYMBOL(ib_dealloc_xrcd);
 
+/**
+ * ib_create_wq - Creates a WQ associated with the specified protection
+ * domain.
+ * @pd: The protection domain associated with the WQ.
+ * @wq_init_attr: A list of initial attributes required to create the
+ * WQ. If WQ creation succeeds, then the attributes are updated to
+ * the actual capabilities of the created WQ.
+ *
+ * wq_init_attr->max_wr and wq_init_attr->max_sge determine
+ * the requested size of the WQ, and set to the actual values allocated
+ * on return.
+ * If ib_create_wq() succeeds, then max_wr and max_sge will always be
+ * at least as large as the requested values.
+ */
+struct ib_wq *ib_create_wq(struct ib_pd *pd,
+			   struct ib_wq_init_attr *wq_attr)
+{
+	struct ib_wq *wq;
+
+	if (!pd->device->create_wq)
+		return ERR_PTR(-ENOSYS);
+
+	wq = pd->device->create_wq(pd, wq_attr, NULL);
+	if (!IS_ERR(wq)) {
+		wq->event_handler = wq_attr->event_handler;
+		wq->wq_context = wq_attr->wq_context;
+		wq->wq_type = wq_attr->wq_type;
+		wq->cq = wq_attr->cq;
+		wq->device = pd->device;
+		wq->pd = pd;
+		wq->uobject = NULL;
+		atomic_inc(&pd->usecnt);
+		atomic_inc(&wq_attr->cq->usecnt);
+		atomic_set(&wq->usecnt, 0);
+	}
+	return wq;
+}
+EXPORT_SYMBOL(ib_create_wq);
+
+/**
+ * ib_destroy_wq - Destroys the specified WQ.
+ * @wq: The WQ to destroy.
+ */
+int ib_destroy_wq(struct ib_wq *wq)
+{
+	int err;
+	struct ib_cq *cq = wq->cq;
+	struct ib_pd *pd = wq->pd;
+
+	if (atomic_read(&wq->usecnt))
+		return -EBUSY;
+
+	err = wq->device->destroy_wq(wq);
+	if (!err) {
+		atomic_dec(&pd->usecnt);
+		atomic_dec(&cq->usecnt);
+	}
+	return err;
+}
+EXPORT_SYMBOL(ib_destroy_wq);
+
+/**
+ * ib_modify_wq - Modifies the specified WQ.
+ * @wq: The WQ to modify.
+ * @wq_attr: On input, specifies the WQ attributes to modify.
+ * @wq_attr_mask: A bit-mask used to specify which attributes of the WQ
+ *   are being modified.
+ * On output, the current values of selected WQ attributes are returned.
+ */
+int ib_modify_wq(struct ib_wq *wq, struct ib_wq_attr *wq_attr,
+		 u32 wq_attr_mask)
+{
+	int err;
+
+	if (!wq->device->modify_wq)
+		return -ENOSYS;
+
+	err = wq->device->modify_wq(wq, wq_attr, wq_attr_mask, NULL);
+	return err;
+}
+EXPORT_SYMBOL(ib_modify_wq);
+
 struct ib_flow *ib_create_flow(struct ib_qp *qp,
 			       struct ib_flow_attr *flow_attr,
 			       int domain)

include/rdma/ib_verbs.h

@@ -1428,6 +1428,48 @@ struct ib_srq {
 	} ext;
 };
 
+enum ib_wq_type {
+	IB_WQT_RQ
+};
+
+enum ib_wq_state {
+	IB_WQS_RESET,
+	IB_WQS_RDY,
+	IB_WQS_ERR
+};
+
+struct ib_wq {
+	struct ib_device       *device;
+	struct ib_uobject      *uobject;
+	void		    *wq_context;
+	void		    (*event_handler)(struct ib_event *, void *);
+	struct ib_pd	       *pd;
+	struct ib_cq	       *cq;
+	u32		wq_num;
+	enum ib_wq_state       state;
+	enum ib_wq_type	wq_type;
+	atomic_t		usecnt;
+};
+
+struct ib_wq_init_attr {
+	void		       *wq_context;
+	enum ib_wq_type	wq_type;
+	u32		max_wr;
+	u32		max_sge;
+	struct	ib_cq	       *cq;
+	void		    (*event_handler)(struct ib_event *, void *);
+};
+
+enum ib_wq_attr_mask {
+	IB_WQ_STATE	= 1 << 0,
+	IB_WQ_CUR_STATE	= 1 << 1,
+};
+
+struct ib_wq_attr {
+	enum	ib_wq_state	wq_state;
+	enum	ib_wq_state	curr_wq_state;
+};
+
 struct ib_qp {
 	struct ib_device       *device;
 	struct ib_pd	       *pd;
@@ -1921,7 +1963,14 @@ struct ib_device {
 						   struct ifla_vf_stats *stats);
 	int			   (*set_vf_guid)(struct ib_device *device, int vf, u8 port, u64 guid,
 						  int type);
-
+	struct ib_wq *		   (*create_wq)(struct ib_pd *pd,
+						struct ib_wq_init_attr *init_attr,
+						struct ib_udata *udata);
+	int			   (*destroy_wq)(struct ib_wq *wq);
+	int			   (*modify_wq)(struct ib_wq *wq,
+						struct ib_wq_attr *attr,
+						u32 wq_attr_mask,
+						struct ib_udata *udata);
 	struct ib_dma_mapping_ops   *dma_ops;
 
 	struct module               *owner;
@@ -3167,6 +3216,11 @@ int ib_check_mr_status(struct ib_mr *mr, u32 check_mask,
 struct net_device *ib_get_net_dev_by_params(struct ib_device *dev, u8 port,
 					    u16 pkey, const union ib_gid *gid,
 					    const struct sockaddr *addr);
+struct ib_wq *ib_create_wq(struct ib_pd *pd,
+			   struct ib_wq_init_attr *init_attr);
+int ib_destroy_wq(struct ib_wq *wq);
+int ib_modify_wq(struct ib_wq *wq, struct ib_wq_attr *attr,
+		 u32 wq_attr_mask);
 
 int ib_map_mr_sg(struct ib_mr *mr, struct scatterlist *sg, int sg_nents,
 		 unsigned int *sg_offset, unsigned int page_size);