IB/srp: Separate target and channel variables

Changes in this patch:
- Move channel variables into a new structure (struct srp_rdma_ch).
- Add an srp_target_port pointer, 'lock' and 'comp_vector' members
  in struct srp_rdma_ch.
- Add code to initialize these three new member variables.
- Many boring "target->" into "ch->" changes.
- The cm_id and completion handler context pointers are now of type
  srp_rdma_ch * instead of srp_target_port *.
- Three kzalloc(a * b, f) calls have been changed into kcalloc(a, b, f)
  to avoid that this patch would trigger a checkpatch warning.
- Two casts from u64 into unsigned long long have been left out
  because these are superfluous. Since considerable time u64 is
  defined as unsigned long long for all architectures supported by
  the Linux kernel.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/infiniband/ulp/srp/ib_srp.h

@@ -130,7 +130,11 @@ struct srp_request {
 	short			index;
 };
 
-struct srp_target_port {
+/**
+ * struct srp_rdma_ch
+ * @comp_vector: Completion vector used by this RDMA channel.
+ */
+struct srp_rdma_ch {
 	/* These are RW in the hot path, and commonly used together */
 	struct list_head	free_tx;
 	struct list_head	free_reqs;
@@ -138,13 +142,48 @@ struct srp_target_port {
 	s32			req_lim;
 
 	/* These are read-only in the hot path */
-	struct ib_cq	       *send_cq ____cacheline_aligned_in_smp;
+	struct srp_target_port *target ____cacheline_aligned_in_smp;
+	struct ib_cq	       *send_cq;
 	struct ib_cq	       *recv_cq;
 	struct ib_qp	       *qp;
 	union {
 		struct ib_fmr_pool     *fmr_pool;
 		struct srp_fr_pool     *fr_pool;
 	};
+
+	/* Everything above this point is used in the hot path of
+	 * command processing. Try to keep them packed into cachelines.
+	 */
+
+	struct completion	done;
+	int			status;
+
+	struct ib_sa_path_rec	path;
+	struct ib_sa_query     *path_query;
+	int			path_query_id;
+
+	struct ib_cm_id	       *cm_id;
+	struct srp_iu	      **tx_ring;
+	struct srp_iu	      **rx_ring;
+	struct srp_request     *req_ring;
+	int			max_ti_iu_len;
+	int			comp_vector;
+
+	struct completion	tsk_mgmt_done;
+	u8			tsk_mgmt_status;
+};
+
+/**
+ * struct srp_target_port
+ * @comp_vector: Completion vector used by the first RDMA channel created for
+ *   this target port.
+ */
+struct srp_target_port {
+	/* read and written in the hot path */
+	spinlock_t		lock;
+
+	struct srp_rdma_ch	ch;
+	/* read only in the hot path */
 	u32			lkey;
 	u32			rkey;
 	enum srp_target_state	state;
@@ -153,10 +192,7 @@ struct srp_target_port {
 	unsigned int		indirect_size;
 	bool			allow_ext_sg;
 
-	/* Everything above this point is used in the hot path of
-	 * command processing. Try to keep them packed into cachelines.
-	 */
-
+	/* other member variables */
 	union ib_gid		sgid;
 	__be64			id_ext;
 	__be64			ioc_guid;
@@ -176,33 +212,17 @@ struct srp_target_port {
 
 	union ib_gid		orig_dgid;
 	__be16			pkey;
-	struct ib_sa_path_rec	path;
-	struct ib_sa_query     *path_query;
-	int			path_query_id;
 
 	u32			rq_tmo_jiffies;
 	bool			connected;
 
-	struct ib_cm_id	       *cm_id;
-
-	int			max_ti_iu_len;
-
 	int			zero_req_lim;
 
-	struct srp_iu	       **tx_ring;
-	struct srp_iu	       **rx_ring;
-	struct srp_request	*req_ring;
-
 	struct work_struct	tl_err_work;
 	struct work_struct	remove_work;
 
 	struct list_head	list;
-	struct completion	done;
-	int			status;
 	bool			qp_in_error;
-
-	struct completion	tsk_mgmt_done;
-	u8			tsk_mgmt_status;
 };
 
 struct srp_iu {