transport.c

linux 内核源代码

		goto out2;

	/*
	 * Allocate pre-registered send and receive buffers for headers and
	 * any inline data. Also specify any padding which will be provided
	 * from a preregistered zero buffer.
	 */
	rc = rpcrdma_buffer_create(&new_xprt->rx_buf, new_ep, &new_xprt->rx_ia,
				&new_xprt->rx_data);
	if (rc)
		goto out3;

	/*
	 * Register a callback for connection events. This is necessary because
	 * connection loss notification is async. We also catch connection loss
	 * when reaping receives.
	 */
	INIT_DELAYED_WORK(&new_xprt->rdma_connect, xprt_rdma_connect_worker);
	new_ep->rep_func = rpcrdma_conn_func;
	new_ep->rep_xprt = xprt;

	xprt_rdma_format_addresses(xprt);

	if (!try_module_get(THIS_MODULE))
		goto out4;

	return xprt;

out4:
	xprt_rdma_free_addresses(xprt);
	rc = -EINVAL;
out3:
	(void) rpcrdma_ep_destroy(new_ep, &new_xprt->rx_ia);
out2:
	rpcrdma_ia_close(&new_xprt->rx_ia);
out1:
	kfree(xprt->slot);
	kfree(xprt);
	return ERR_PTR(rc);
}

/*
 * Close a connection, during shutdown or timeout/reconnect
 */
static void
xprt_rdma_close(struct rpc_xprt *xprt)
{
	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);

	dprintk("RPC:       %s: closing\n", __func__);
	xprt_disconnect(xprt);
	(void) rpcrdma_ep_disconnect(&r_xprt->rx_ep, &r_xprt->rx_ia);
}

static void
xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port)
{
	struct sockaddr_in *sap;

	sap = (struct sockaddr_in *)&xprt->addr;
	sap->sin_port = htons(port);
	sap = (struct sockaddr_in *)&rpcx_to_rdmad(xprt).addr;
	sap->sin_port = htons(port);
	dprintk("RPC:       %s: %u\n", __func__, port);
}

static void
xprt_rdma_connect(struct rpc_task *task)
{
	struct rpc_xprt *xprt = (struct rpc_xprt *)task->tk_xprt;
	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);

	if (!xprt_test_and_set_connecting(xprt)) {
		if (r_xprt->rx_ep.rep_connected != 0) {
			/* Reconnect */
			schedule_delayed_work(&r_xprt->rdma_connect,
				xprt->reestablish_timeout);
		} else {
			schedule_delayed_work(&r_xprt->rdma_connect, 0);
			if (!RPC_IS_ASYNC(task))
				flush_scheduled_work();
		}
	}
}

static int
xprt_rdma_reserve_xprt(struct rpc_task *task)
{
	struct rpc_xprt *xprt = task->tk_xprt;
	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
	int credits = atomic_read(&r_xprt->rx_buf.rb_credits);

	/* == RPC_CWNDSCALE @ init, but *after* setup */
	if (r_xprt->rx_buf.rb_cwndscale == 0UL) {
		r_xprt->rx_buf.rb_cwndscale = xprt->cwnd;
		dprintk("RPC:       %s: cwndscale %lu\n", __func__,
			r_xprt->rx_buf.rb_cwndscale);
		BUG_ON(r_xprt->rx_buf.rb_cwndscale <= 0);
	}
	xprt->cwnd = credits * r_xprt->rx_buf.rb_cwndscale;
	return xprt_reserve_xprt_cong(task);
}

/*
 * The RDMA allocate/free functions need the task structure as a place
 * to hide the struct rpcrdma_req, which is necessary for the actual send/recv
 * sequence. For this reason, the recv buffers are attached to send
 * buffers for portions of the RPC. Note that the RPC layer allocates
 * both send and receive buffers in the same call. We may register
 * the receive buffer portion when using reply chunks.
 */
static void *
xprt_rdma_allocate(struct rpc_task *task, size_t size)
{
	struct rpc_xprt *xprt = task->tk_xprt;
	struct rpcrdma_req *req, *nreq;

	req = rpcrdma_buffer_get(&rpcx_to_rdmax(xprt)->rx_buf);
	BUG_ON(NULL == req);

	if (size > req->rl_size) {
		dprintk("RPC:       %s: size %zd too large for buffer[%zd]: "
			"prog %d vers %d proc %d\n",
			__func__, size, req->rl_size,
			task->tk_client->cl_prog, task->tk_client->cl_vers,
			task->tk_msg.rpc_proc->p_proc);
		/*
		 * Outgoing length shortage. Our inline write max must have
		 * been configured to perform direct i/o.
		 *
		 * This is therefore a large metadata operation, and the
		 * allocate call was made on the maximum possible message,
		 * e.g. containing long filename(s) or symlink data. In
		 * fact, while these metadata operations *might* carry
		 * large outgoing payloads, they rarely *do*. However, we
		 * have to commit to the request here, so reallocate and
		 * register it now. The data path will never require this
		 * reallocation.
		 *
		 * If the allocation or registration fails, the RPC framework
		 * will (doggedly) retry.
		 */
		if (rpcx_to_rdmax(xprt)->rx_ia.ri_memreg_strategy ==
				RPCRDMA_BOUNCEBUFFERS) {
			/* forced to "pure inline" */
			dprintk("RPC:       %s: too much data (%zd) for inline "
					"(r/w max %d/%d)\n", __func__, size,
					rpcx_to_rdmad(xprt).inline_rsize,
					rpcx_to_rdmad(xprt).inline_wsize);
			size = req->rl_size;
			rpc_exit(task, -EIO);		/* fail the operation */
			rpcx_to_rdmax(xprt)->rx_stats.failed_marshal_count++;
			goto out;
		}
		if (task->tk_flags & RPC_TASK_SWAPPER)
			nreq = kmalloc(sizeof *req + size, GFP_ATOMIC);
		else
			nreq = kmalloc(sizeof *req + size, GFP_NOFS);
		if (nreq == NULL)
			goto outfail;

		if (rpcrdma_register_internal(&rpcx_to_rdmax(xprt)->rx_ia,
				nreq->rl_base, size + sizeof(struct rpcrdma_req)
				- offsetof(struct rpcrdma_req, rl_base),
				&nreq->rl_handle, &nreq->rl_iov)) {
			kfree(nreq);
			goto outfail;
		}
		rpcx_to_rdmax(xprt)->rx_stats.hardway_register_count += size;
		nreq->rl_size = size;
		nreq->rl_niovs = 0;
		nreq->rl_nchunks = 0;
		nreq->rl_buffer = (struct rpcrdma_buffer *)req;
		nreq->rl_reply = req->rl_reply;
		memcpy(nreq->rl_segments,
			req->rl_segments, sizeof nreq->rl_segments);
		/* flag the swap with an unused field */
		nreq->rl_iov.length = 0;
		req->rl_reply = NULL;
		req = nreq;
	}
	dprintk("RPC:       %s: size %zd, request 0x%p\n", __func__, size, req);
out:
	return req->rl_xdr_buf;

outfail:
	rpcrdma_buffer_put(req);
	rpcx_to_rdmax(xprt)->rx_stats.failed_marshal_count++;
	return NULL;
}

/*
 * This function returns all RDMA resources to the pool.
 */
static void
xprt_rdma_free(void *buffer)
{
	struct rpcrdma_req *req;
	struct rpcrdma_xprt *r_xprt;
	struct rpcrdma_rep *rep;
	int i;

	if (buffer == NULL)
		return;

	req = container_of(buffer, struct rpcrdma_req, rl_xdr_buf[0]);
	r_xprt = container_of(req->rl_buffer, struct rpcrdma_xprt, rx_buf);
	rep = req->rl_reply;

	dprintk("RPC:       %s: called on 0x%p%s\n",
		__func__, rep, (rep && rep->rr_func) ? " (with waiter)" : "");

	/*
	 * Finish the deregistration. When using mw bind, this was
	 * begun in rpcrdma_reply_handler(). In all other modes, we
	 * do it here, in thread context. The process is considered
	 * complete when the rr_func vector becomes NULL - this
	 * was put in place during rpcrdma_reply_handler() - the wait
	 * call below will not block if the dereg is "done". If
	 * interrupted, our framework will clean up.
	 */
	for (i = 0; req->rl_nchunks;) {
		--req->rl_nchunks;
		i += rpcrdma_deregister_external(
			&req->rl_segments[i], r_xprt, NULL);
	}

	if (rep && wait_event_interruptible(rep->rr_unbind, !rep->rr_func)) {
		rep->rr_func = NULL;	/* abandon the callback */
		req->rl_reply = NULL;
	}

	if (req->rl_iov.length == 0) {	/* see allocate above */
		struct rpcrdma_req *oreq = (struct rpcrdma_req *)req->rl_buffer;
		oreq->rl_reply = req->rl_reply;
		(void) rpcrdma_deregister_internal(&r_xprt->rx_ia,
						   req->rl_handle,
						   &req->rl_iov);
		kfree(req);
		req = oreq;
	}

	/* Put back request+reply buffers */
	rpcrdma_buffer_put(req);
}

/*
 * send_request invokes the meat of RPC RDMA. It must do the following:
 *  1.  Marshal the RPC request into an RPC RDMA request, which means
 *	putting a header in front of data, and creating IOVs for RDMA
 *	from those in the request.
 *  2.  In marshaling, detect opportunities for RDMA, and use them.
 *  3.  Post a recv message to set up asynch completion, then send
 *	the request (rpcrdma_ep_post).
 *  4.  No partial sends are possible in the RPC-RDMA protocol (as in UDP).
 */

static int
xprt_rdma_send_request(struct rpc_task *task)
{
	struct rpc_rqst *rqst = task->tk_rqstp;
	struct rpc_xprt *xprt = task->tk_xprt;
	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);

	/* marshal the send itself */
	if (req->rl_niovs == 0 && rpcrdma_marshal_req(rqst) != 0) {
		r_xprt->rx_stats.failed_marshal_count++;
		dprintk("RPC:       %s: rpcrdma_marshal_req failed\n",
			__func__);
		return -EIO;
	}

	if (req->rl_reply == NULL) 		/* e.g. reconnection */
		rpcrdma_recv_buffer_get(req);

	if (req->rl_reply) {
		req->rl_reply->rr_func = rpcrdma_reply_handler;
		/* this need only be done once, but... */
		req->rl_reply->rr_xprt = xprt;
	}

	if (rpcrdma_ep_post(&r_xprt->rx_ia, &r_xprt->rx_ep, req)) {
		xprt_disconnect(xprt);
		return -ENOTCONN;	/* implies disconnect */
	}

	rqst->rq_bytes_sent = 0;
	return 0;
}

static void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
{
	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
	long idle_time = 0;

	if (xprt_connected(xprt))
		idle_time = (long)(jiffies - xprt->last_used) / HZ;

	seq_printf(seq,
	  "\txprt:\trdma %u %lu %lu %lu %ld %lu %lu %lu %Lu %Lu "
	  "%lu %lu %lu %Lu %Lu %Lu %Lu %lu %lu %lu\n",

	   0,	/* need a local port? */
	   xprt->stat.bind_count,
	   xprt->stat.connect_count,
	   xprt->stat.connect_time,
	   idle_time,
	   xprt->stat.sends,
	   xprt->stat.recvs,
	   xprt->stat.bad_xids,
	   xprt->stat.req_u,
	   xprt->stat.bklog_u,

	   r_xprt->rx_stats.read_chunk_count,
	   r_xprt->rx_stats.write_chunk_count,
	   r_xprt->rx_stats.reply_chunk_count,
	   r_xprt->rx_stats.total_rdma_request,
	   r_xprt->rx_stats.total_rdma_reply,
	   r_xprt->rx_stats.pullup_copy_count,
	   r_xprt->rx_stats.fixup_copy_count,
	   r_xprt->rx_stats.hardway_register_count,
	   r_xprt->rx_stats.failed_marshal_count,
	   r_xprt->rx_stats.bad_reply_count);
}

/*
 * Plumbing for rpc transport switch and kernel module
 */

static struct rpc_xprt_ops xprt_rdma_procs = {
	.reserve_xprt		= xprt_rdma_reserve_xprt,
	.release_xprt		= xprt_release_xprt_cong, /* sunrpc/xprt.c */
	.release_request	= xprt_release_rqst_cong,       /* ditto */
	.set_retrans_timeout	= xprt_set_retrans_timeout_def, /* ditto */
	.rpcbind		= rpcb_getport_async,	/* sunrpc/rpcb_clnt.c */
	.set_port		= xprt_rdma_set_port,
	.connect		= xprt_rdma_connect,
	.buf_alloc		= xprt_rdma_allocate,
	.buf_free		= xprt_rdma_free,
	.send_request		= xprt_rdma_send_request,
	.close			= xprt_rdma_close,
	.destroy		= xprt_rdma_destroy,
	.print_stats		= xprt_rdma_print_stats
};

static struct xprt_class xprt_rdma = {
	.list			= LIST_HEAD_INIT(xprt_rdma.list),
	.name			= "rdma",
	.owner			= THIS_MODULE,
	.ident			= XPRT_TRANSPORT_RDMA,
	.setup			= xprt_setup_rdma,
};

static void __exit xprt_rdma_cleanup(void)
{
	int rc;

	dprintk("RPCRDMA Module Removed, deregister RPC RDMA transport\n");
#ifdef RPC_DEBUG
	if (sunrpc_table_header) {
		unregister_sysctl_table(sunrpc_table_header);
		sunrpc_table_header = NULL;
	}
#endif
	rc = xprt_unregister_transport(&xprt_rdma);
	if (rc)
		dprintk("RPC:       %s: xprt_unregister returned %i\n",
			__func__, rc);
}

static int __init xprt_rdma_init(void)
{
	int rc;

	rc = xprt_register_transport(&xprt_rdma);

	if (rc)
		return rc;

	dprintk(KERN_INFO "RPCRDMA Module Init, register RPC RDMA transport\n");

	dprintk(KERN_INFO "Defaults:\n");
	dprintk(KERN_INFO "\tSlots %d\n"
		"\tMaxInlineRead %d\n\tMaxInlineWrite %d\n",
		xprt_rdma_slot_table_entries,
		xprt_rdma_max_inline_read, xprt_rdma_max_inline_write);
	dprintk(KERN_INFO "\tPadding %d\n\tMemreg %d\n",
		xprt_rdma_inline_write_padding, xprt_rdma_memreg_strategy);

#ifdef RPC_DEBUG
	if (!sunrpc_table_header)
		sunrpc_table_header = register_sysctl_table(sunrpc_table);
#endif
	return 0;
}

module_init(xprt_rdma_init);
module_exit(xprt_rdma_cleanup);