RPCRDMA: rpc rdma transport switch

This implements the configuration and building of the core transport
switch implementation of the rpcrdma transport. Stubs are provided for
the rpcrdma protocol handling, and the infiniband/iwarp verbs interface.
These are provided in following patches.

Signed-off-by: Tom Talpey <talpey@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 330 insertions, 0 deletions

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
new file mode 100644
index 000000000000..2427822f8bd4
--- /dev/null
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -0,0 +1,330 @@
+/*
+ * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the BSD-type
+ * license below:
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *      Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *      Redistributions in binary form must reproduce the above
+ *      copyright notice, this list of conditions and the following
+ *      disclaimer in the documentation and/or other materials provided
+ *      with the distribution.
+ *
+ *      Neither the name of the Network Appliance, Inc. nor the names of
+ *      its contributors may be used to endorse or promote products
+ *      derived from this software without specific prior written
+ *      permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _LINUX_SUNRPC_XPRT_RDMA_H
+#define _LINUX_SUNRPC_XPRT_RDMA_H
+
+#include <linux/wait.h> 		/* wait_queue_head_t, etc */
+#include <linux/spinlock.h> 		/* spinlock_t, etc */
+#include <asm/atomic.h>			/* atomic_t, etc */
+
+#include <rdma/rdma_cm.h>		/* RDMA connection api */
+#include <rdma/ib_verbs.h>		/* RDMA verbs api */
+
+#include <linux/sunrpc/clnt.h> 		/* rpc_xprt */
+#include <linux/sunrpc/rpc_rdma.h> 	/* RPC/RDMA protocol */
+#include <linux/sunrpc/xprtrdma.h> 	/* xprt parameters */
+
+/*
+ * Interface Adapter -- one per transport instance
+ */
+struct rpcrdma_ia {
+	struct rdma_cm_id 	*ri_id;
+	struct ib_pd		*ri_pd;
+	struct ib_mr		*ri_bind_mem;
+	struct completion	ri_done;
+	int			ri_async_rc;
+	enum rpcrdma_memreg	ri_memreg_strategy;
+};
+
+/*
+ * RDMA Endpoint -- one per transport instance
+ */
+
+struct rpcrdma_ep {
+	atomic_t		rep_cqcount;
+	int			rep_cqinit;
+	int			rep_connected;
+	struct rpcrdma_ia	*rep_ia;
+	struct ib_cq		*rep_cq;
+	struct ib_qp_init_attr	rep_attr;
+	wait_queue_head_t 	rep_connect_wait;
+	struct ib_sge		rep_pad;	/* holds zeroed pad */
+	struct ib_mr		*rep_pad_mr;	/* holds zeroed pad */
+	void			(*rep_func)(struct rpcrdma_ep *);
+	struct rpc_xprt		*rep_xprt;	/* for rep_func */
+	struct rdma_conn_param	rep_remote_cma;
+	struct sockaddr_storage	rep_remote_addr;
+};
+
+#define INIT_CQCOUNT(ep) atomic_set(&(ep)->rep_cqcount, (ep)->rep_cqinit)
+#define DECR_CQCOUNT(ep) atomic_sub_return(1, &(ep)->rep_cqcount)
+
+/*
+ * struct rpcrdma_rep -- this structure encapsulates state required to recv
+ * and complete a reply, asychronously. It needs several pieces of
+ * state:
+ *   o recv buffer (posted to provider)
+ *   o ib_sge (also donated to provider)
+ *   o status of reply (length, success or not)
+ *   o bookkeeping state to get run by tasklet (list, etc)
+ *
+ * These are allocated during initialization, per-transport instance;
+ * however, the tasklet execution list itself is global, as it should
+ * always be pretty short.
+ *
+ * N of these are associated with a transport instance, and stored in
+ * struct rpcrdma_buffer. N is the max number of outstanding requests.
+ */
+
+/* temporary static scatter/gather max */
+#define RPCRDMA_MAX_DATA_SEGS	(8)	/* max scatter/gather */
+#define RPCRDMA_MAX_SEGS 	(RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = 2 */
+#define MAX_RPCRDMAHDR	(\
+	/* max supported RPC/RDMA header */ \
+	sizeof(struct rpcrdma_msg) + (2 * sizeof(u32)) + \
+	(sizeof(struct rpcrdma_read_chunk) * RPCRDMA_MAX_SEGS) + sizeof(u32))
+
+struct rpcrdma_buffer;
+
+struct rpcrdma_rep {
+	unsigned int	rr_len;		/* actual received reply length */
+	struct rpcrdma_buffer *rr_buffer; /* home base for this structure */
+	struct rpc_xprt	*rr_xprt;	/* needed for request/reply matching */
+	void (*rr_func)(struct rpcrdma_rep *);/* called by tasklet in softint */
+	struct list_head rr_list;	/* tasklet list */
+	wait_queue_head_t rr_unbind;	/* optional unbind wait */
+	struct ib_sge	rr_iov;		/* for posting */
+	struct ib_mr	*rr_handle;	/* handle for mem in rr_iov */
+	char	rr_base[MAX_RPCRDMAHDR]; /* minimal inline receive buffer */
+};
+
+/*
+ * struct rpcrdma_req -- structure central to the request/reply sequence.
+ *
+ * N of these are associated with a transport instance, and stored in
+ * struct rpcrdma_buffer. N is the max number of outstanding requests.
+ *
+ * It includes pre-registered buffer memory for send AND recv.
+ * The recv buffer, however, is not owned by this structure, and
+ * is "donated" to the hardware when a recv is posted. When a
+ * reply is handled, the recv buffer used is given back to the
+ * struct rpcrdma_req associated with the request.
+ *
+ * In addition to the basic memory, this structure includes an array
+ * of iovs for send operations. The reason is that the iovs passed to
+ * ib_post_{send,recv} must not be modified until the work request
+ * completes.
+ *
+ * NOTES:
+ *   o RPCRDMA_MAX_SEGS is the max number of addressible chunk elements we
+ *     marshal. The number needed varies depending on the iov lists that
+ *     are passed to us, the memory registration mode we are in, and if
+ *     physical addressing is used, the layout.
+ */
+
+struct rpcrdma_mr_seg {		/* chunk descriptors */
+	union {				/* chunk memory handles */
+		struct ib_mr	*rl_mr;		/* if registered directly */
+		struct rpcrdma_mw {		/* if registered from region */
+			union {
+				struct ib_mw	*mw;
+				struct ib_fmr	*fmr;
+			} r;
+			struct list_head mw_list;
+		} *rl_mw;
+	} mr_chunk;
+	u64		mr_base;	/* registration result */
+	u32		mr_rkey;	/* registration result */
+	u32		mr_len;		/* length of chunk or segment */
+	int		mr_nsegs;	/* number of segments in chunk or 0 */
+	enum dma_data_direction	mr_dir;	/* segment mapping direction */
+	dma_addr_t	mr_dma;		/* segment mapping address */
+	size_t		mr_dmalen;	/* segment mapping length */
+	struct page	*mr_page;	/* owning page, if any */
+	char		*mr_offset;	/* kva if no page, else offset */
+};
+
+struct rpcrdma_req {
+	size_t 		rl_size;	/* actual length of buffer */
+	unsigned int	rl_niovs;	/* 0, 2 or 4 */
+	unsigned int	rl_nchunks;	/* non-zero if chunks */
+	struct rpcrdma_buffer *rl_buffer; /* home base for this structure */
+	struct rpcrdma_rep	*rl_reply;/* holder for reply buffer */
+	struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS];/* chunk segments */
+	struct ib_sge	rl_send_iov[4];	/* for active requests */
+	struct ib_sge	rl_iov;		/* for posting */
+	struct ib_mr	*rl_handle;	/* handle for mem in rl_iov */
+	char		rl_base[MAX_RPCRDMAHDR]; /* start of actual buffer */
+	__u32 		rl_xdr_buf[0];	/* start of returned rpc rq_buffer */
+};
+#define rpcr_to_rdmar(r) \
+	container_of((r)->rq_buffer, struct rpcrdma_req, rl_xdr_buf[0])
+
+/*
+ * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
+ * inline requests/replies, and client/server credits.
+ *
+ * One of these is associated with a transport instance
+ */
+struct rpcrdma_buffer {
+	spinlock_t	rb_lock;	/* protects indexes */
+	atomic_t	rb_credits;	/* most recent server credits */
+	unsigned long	rb_cwndscale;	/* cached framework rpc_cwndscale */
+	int		rb_max_requests;/* client max requests */
+	struct list_head rb_mws;	/* optional memory windows/fmrs */
+	int		rb_send_index;
+	struct rpcrdma_req	**rb_send_bufs;
+	int		rb_recv_index;
+	struct rpcrdma_rep	**rb_recv_bufs;
+	char		*rb_pool;
+};
+#define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
+
+/*
+ * Internal structure for transport instance creation. This
+ * exists primarily for modularity.
+ *
+ * This data should be set with mount options
+ */
+struct rpcrdma_create_data_internal {
+	struct sockaddr_storage	addr;	/* RDMA server address */
+	unsigned int	max_requests;	/* max requests (slots) in flight */
+	unsigned int	rsize;		/* mount rsize - max read hdr+data */
+	unsigned int	wsize;		/* mount wsize - max write hdr+data */
+	unsigned int	inline_rsize;	/* max non-rdma read data payload */
+	unsigned int	inline_wsize;	/* max non-rdma write data payload */
+	unsigned int	padding;	/* non-rdma write header padding */
+};
+
+#define RPCRDMA_INLINE_READ_THRESHOLD(rq) \
+	(rpcx_to_rdmad(rq->rq_task->tk_xprt).inline_rsize)
+
+#define RPCRDMA_INLINE_WRITE_THRESHOLD(rq)\
+	(rpcx_to_rdmad(rq->rq_task->tk_xprt).inline_wsize)
+
+#define RPCRDMA_INLINE_PAD_VALUE(rq)\
+	rpcx_to_rdmad(rq->rq_task->tk_xprt).padding
+
+/*
+ * Statistics for RPCRDMA
+ */
+struct rpcrdma_stats {
+	unsigned long		read_chunk_count;
+	unsigned long		write_chunk_count;
+	unsigned long		reply_chunk_count;
+
+	unsigned long long	total_rdma_request;
+	unsigned long long	total_rdma_reply;
+
+	unsigned long long	pullup_copy_count;
+	unsigned long long	fixup_copy_count;
+	unsigned long		hardway_register_count;
+	unsigned long		failed_marshal_count;
+	unsigned long		bad_reply_count;
+};
+
+/*
+ * RPCRDMA transport -- encapsulates the structures above for
+ * integration with RPC.
+ *
+ * The contained structures are embedded, not pointers,
+ * for convenience. This structure need not be visible externally.
+ *
+ * It is allocated and initialized during mount, and released
+ * during unmount.
+ */
+struct rpcrdma_xprt {
+	struct rpc_xprt		xprt;
+	struct rpcrdma_ia	rx_ia;
+	struct rpcrdma_ep	rx_ep;
+	struct rpcrdma_buffer	rx_buf;
+	struct rpcrdma_create_data_internal rx_data;
+	struct delayed_work	rdma_connect;
+	struct rpcrdma_stats	rx_stats;
+};
+
+#define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, xprt)
+#define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
+
+/*
+ * Interface Adapter calls - xprtrdma/verbs.c
+ */
+int rpcrdma_ia_open(struct rpcrdma_xprt *, struct sockaddr *, int);
+void rpcrdma_ia_close(struct rpcrdma_ia *);
+
+/*
+ * Endpoint calls - xprtrdma/verbs.c
+ */
+int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
+				struct rpcrdma_create_data_internal *);
+int rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
+int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
+int rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
+
+int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
+				struct rpcrdma_req *);
+int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_ep *,
+				struct rpcrdma_rep *);
+
+/*
+ * Buffer calls - xprtrdma/verbs.c
+ */
+int rpcrdma_buffer_create(struct rpcrdma_buffer *, struct rpcrdma_ep *,
+				struct rpcrdma_ia *,
+				struct rpcrdma_create_data_internal *);
+void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
+
+struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
+void rpcrdma_buffer_put(struct rpcrdma_req *);
+void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
+void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
+
+int rpcrdma_register_internal(struct rpcrdma_ia *, void *, int,
+				struct ib_mr **, struct ib_sge *);
+int rpcrdma_deregister_internal(struct rpcrdma_ia *,
+				struct ib_mr *, struct ib_sge *);
+
+int rpcrdma_register_external(struct rpcrdma_mr_seg *,
+				int, int, struct rpcrdma_xprt *);
+int rpcrdma_deregister_external(struct rpcrdma_mr_seg *,
+				struct rpcrdma_xprt *, void *);
+
+/*
+ * RPC/RDMA connection management calls - xprtrdma/rpc_rdma.c
+ */
+void rpcrdma_conn_func(struct rpcrdma_ep *);
+void rpcrdma_reply_handler(struct rpcrdma_rep *);
+
+/*
+ * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
+ */
+int rpcrdma_marshal_req(struct rpc_rqst *);
+
+#endif				/* _LINUX_SUNRPC_XPRT_RDMA_H */