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Commit 262965f5 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
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[PATCH] RPC: separate TCP and UDP socket write paths 



 Split the RPC client's main socket write path into a TCP version and a UDP
 version to eliminate another dependency on the "xprt->stream" variable.

 Compiler optimization removes unneeded code from xs_sendpages, as this
 function is now called with some constant arguments.

 We can now cleanly perform transport protocol-specific return code testing
 and error recovery in each path.

 Test-plan:
 Millions of fsx operations.  Performance characterization such as
 "sio" or "iozone".  Examine oprofile results for any changes before and
 after this patch is applied.

 Version: Thu, 11 Aug 2005 16:08:46 -0400

 Signed-off-by: default avatarChuck Lever <cel@netapp.com>
 Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent b0d93ad5

net/sunrpc/xprtsock.c

+128 −87
Original line number Diff line number Diff line
@@ -40,6 +40,12 @@ 
 */

#define XS_MAX_RESVPORT		(800U)



/*

 * How many times to try sending a request on a socket before waiting

 * for the socket buffer to clear.

 */

#define XS_SENDMSG_RETRY	(10U)



#ifdef RPC_DEBUG

# undef  RPC_DEBUG_DATA

# define RPCDBG_FACILITY	RPCDBG_TRANS
@@ -114,13 +120,18 @@ static int xs_send_tail(struct socket *sock, struct xdr_buf *xdr, unsigned int b 
 * @base: starting position in the buffer

 *

 */

static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)

static inline int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)

{

	struct page **ppage = xdr->pages;

	unsigned int len, pglen = xdr->page_len;

	int err, ret = 0;

	ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);



	if (unlikely(!sock))

		return -ENOTCONN;



	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);



	len = xdr->head[0].iov_len;

	if (base < len || (addr != NULL && base == 0)) {

		err = xs_send_head(sock, addr, addrlen, xdr, base, len);
@@ -187,140 +198,162 @@ static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, 
}



/**

 * xs_sendmsg - write an RPC request to a socket

 * @xprt: generic transport

 * @req: the RPC request to write

 * xs_nospace - place task on wait queue if transmit was incomplete

 * @task: task to put to sleep

 *

 */

static int xs_sendmsg(struct rpc_xprt *xprt, struct rpc_rqst *req)

static void xs_nospace(struct rpc_task *task)

{

	struct socket *sock = xprt->sock;

	struct xdr_buf *xdr = &req->rq_snd_buf;

	struct sockaddr *addr = NULL;

	int addrlen = 0;

	unsigned int skip;

	int result;

	struct rpc_rqst *req = task->tk_rqstp;

	struct rpc_xprt *xprt = req->rq_xprt;



	if (!sock)

		return -ENOTCONN;

	dprintk("RPC: %4d xmit incomplete (%u left of %u)\n",

			task->tk_pid, req->rq_slen - req->rq_bytes_sent,

			req->rq_slen);



	if (test_bit(SOCK_ASYNC_NOSPACE, &xprt->sock->flags)) {

		/* Protect against races with write_space */

		spin_lock_bh(&xprt->transport_lock);



		/* Don't race with disconnect */

		if (!xprt_connected(xprt))

			task->tk_status = -ENOTCONN;

		else if (test_bit(SOCK_NOSPACE, &xprt->sock->flags))

			xprt_wait_for_buffer_space(task);



		spin_unlock_bh(&xprt->transport_lock);

	} else

		/* Keep holding the socket if it is blocked */

		rpc_delay(task, HZ>>4);

}



/**

 * xs_udp_send_request - write an RPC request to a UDP socket

 * @task: address of RPC task that manages the state of an RPC request

 *

 * Return values:

 *        0:	The request has been sent

 *   EAGAIN:	The socket was blocked, please call again later to

 *		complete the request

 * ENOTCONN:	Caller needs to invoke connect logic then call again

 *    other:	Some other error occured, the request was not sent

 */

static int xs_udp_send_request(struct rpc_task *task)

{

	struct rpc_rqst *req = task->tk_rqstp;

	struct rpc_xprt *xprt = req->rq_xprt;

	struct xdr_buf *xdr = &req->rq_snd_buf;

	int status;



	xs_pktdump("packet data:",

				req->rq_svec->iov_base,

				req->rq_svec->iov_len);



	/* For UDP, we need to provide an address */

	if (!xprt->stream) {

		addr = (struct sockaddr *) &xprt->addr;

		addrlen = sizeof(xprt->addr);

	}

	/* Don't repeat bytes */

	skip = req->rq_bytes_sent;

	req->rq_xtime = jiffies;

	status = xs_sendpages(xprt->sock, (struct sockaddr *) &xprt->addr,

				sizeof(xprt->addr), xdr, req->rq_bytes_sent);



	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);

	result = xs_sendpages(sock, addr, addrlen, xdr, skip);

	dprintk("RPC:      xs_udp_send_request(%u) = %d\n",

			xdr->len - req->rq_bytes_sent, status);



	dprintk("RPC:      xs_sendmsg(%d) = %d\n", xdr->len - skip, result);

	if (likely(status >= (int) req->rq_slen))

		return 0;



	if (result >= 0)

		return result;

	/* Still some bytes left; set up for a retry later. */

	if (status > 0)

		status = -EAGAIN;



	switch (result) {

	switch (status) {

	case -ENETUNREACH:

	case -EPIPE:

	case -ECONNREFUSED:

		/* When the server has died, an ICMP port unreachable message

		 * prompts ECONNREFUSED. */

	case -EAGAIN:

		break;

	case -ECONNRESET:

	case -ENOTCONN:

	case -EPIPE:

		/* connection broken */

		if (xprt->stream)

			result = -ENOTCONN;

	case -EAGAIN:

		xs_nospace(task);

		break;

	default:

		dprintk("RPC:      sendmsg returned unrecognized error %d\n",

			-status);

		break;

	}

	return result;



	return status;

}



/**

 * xs_send_request - write an RPC request to a socket

 * xs_tcp_send_request - write an RPC request to a TCP socket

 * @task: address of RPC task that manages the state of an RPC request

 *

 * Return values:

 *        0:	The request has been sent

 *   EAGAIN:	The socket was blocked, please call again later to

 *		complete the request

 * ENOTCONN:	Caller needs to invoke connect logic then call again

 *    other:	Some other error occured, the request was not sent

 *

 * XXX: In the case of soft timeouts, should we eventually give up

 *      if the socket is not able to make progress?

 *	if sendmsg is not able to make progress?

 */

static int xs_send_request(struct rpc_task *task)

static int xs_tcp_send_request(struct rpc_task *task)

{

	struct rpc_rqst *req = task->tk_rqstp;

	struct rpc_xprt *xprt = req->rq_xprt;

	struct xdr_buf *xdr = &req->rq_snd_buf;

	u32 *marker = req->rq_svec[0].iov_base;

	int status, retry = 0;



	/* set up everything as needed. */

	/* Write the record marker */

	if (xprt->stream) {

		u32 *marker = req->rq_svec[0].iov_base;



	*marker = htonl(0x80000000|(req->rq_slen-sizeof(*marker)));

	}



	xs_pktdump("packet data:",

				req->rq_svec->iov_base,

				req->rq_svec->iov_len);



	/* Continue transmitting the packet/record. We must be careful

	 * to cope with writespace callbacks arriving _after_ we have

	 * called sendmsg().

	 */

	 * called sendmsg(). */

	while (1) {

		req->rq_xtime = jiffies;

		status = xs_sendmsg(xprt, req);

		status = xs_sendpages(xprt->sock, NULL, 0, xdr,

						req->rq_bytes_sent);



		if (status < 0)

			break;

		dprintk("RPC:      xs_tcp_send_request(%u) = %d\n",

				xdr->len - req->rq_bytes_sent, status);



		if (xprt->stream) {

			req->rq_bytes_sent += status;

		if (unlikely(status < 0))

			break;



		/* If we've sent the entire packet, immediately

		 * reset the count of bytes sent. */

			if (req->rq_bytes_sent >= req->rq_slen) {

		req->rq_bytes_sent += status;

		if (likely(req->rq_bytes_sent >= req->rq_slen)) {

			req->rq_bytes_sent = 0;

			return 0;

		}

		} else {

			if (status >= req->rq_slen)

				return 0;



		status = -EAGAIN;

		if (retry++ > XS_SENDMSG_RETRY)

			break;

	}



		dprintk("RPC: %4d xmit incomplete (%d left of %d)\n",

				task->tk_pid, req->rq_slen - req->rq_bytes_sent,

				req->rq_slen);



		status = -EAGAIN;

		if (retry++ > 50)

	switch (status) {

	case -EAGAIN:

		xs_nospace(task);

		break;

	case -ECONNREFUSED:

	case -ECONNRESET:

	case -ENOTCONN:

	case -EPIPE:

		status = -ENOTCONN;

		break;

	default:

		dprintk("RPC:      sendmsg returned unrecognized error %d\n",

			-status);

		break;

	}



	if (status == -EAGAIN) {

		if (test_bit(SOCK_ASYNC_NOSPACE, &xprt->sock->flags)) {

			/* Protect against races with write_space */

			spin_lock_bh(&xprt->transport_lock);

			/* Don't race with disconnect */

			if (!xprt_connected(xprt))

				task->tk_status = -ENOTCONN;

			else if (test_bit(SOCK_NOSPACE, &xprt->sock->flags))

				xprt_wait_for_buffer_space(task);

			spin_unlock_bh(&xprt->transport_lock);

			return status;

		}

		/* Keep holding the socket if it is blocked */

		rpc_delay(task, HZ>>4);

	}

	return status;

}
@@ -992,10 +1025,18 @@ static void xs_connect(struct rpc_task *task) 
	}

}



static struct rpc_xprt_ops xs_ops = {

static struct rpc_xprt_ops xs_udp_ops = {

	.set_buffer_size	= xs_set_buffer_size,

	.connect		= xs_connect,

	.send_request		= xs_udp_send_request,

	.close			= xs_close,

	.destroy		= xs_destroy,

};



static struct rpc_xprt_ops xs_tcp_ops = {

	.set_buffer_size	= xs_set_buffer_size,

	.connect		= xs_connect,

	.send_request		= xs_send_request,

	.send_request		= xs_tcp_send_request,

	.close			= xs_close,

	.destroy		= xs_destroy,

};
@@ -1033,7 +1074,7 @@ int xs_setup_udp(struct rpc_xprt *xprt, struct rpc_timeout *to) 


	INIT_WORK(&xprt->connect_worker, xs_udp_connect_worker, xprt);



	xprt->ops = &xs_ops;

	xprt->ops = &xs_udp_ops;



	if (to)

		xprt->timeout = *to;
@@ -1072,7 +1113,7 @@ int xs_setup_tcp(struct rpc_xprt *xprt, struct rpc_timeout *to) 


	INIT_WORK(&xprt->connect_worker, xs_tcp_connect_worker, xprt);



	xprt->ops = &xs_ops;

	xprt->ops = &xs_tcp_ops;



	if (to)

		xprt->timeout = *to;