summaryrefslogtreecommitdiffstats
path: root/net/sunrpc/xprt.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/sunrpc/xprt.c')
-rw-r--r--net/sunrpc/xprt.c1678
1 files changed, 1678 insertions, 0 deletions
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
new file mode 100644
index 000000000000..c74a6bb94074
--- /dev/null
+++ b/net/sunrpc/xprt.c
@@ -0,0 +1,1678 @@
+/*
+ * linux/net/sunrpc/xprt.c
+ *
+ * This is a generic RPC call interface supporting congestion avoidance,
+ * and asynchronous calls.
+ *
+ * The interface works like this:
+ *
+ * - When a process places a call, it allocates a request slot if
+ * one is available. Otherwise, it sleeps on the backlog queue
+ * (xprt_reserve).
+ * - Next, the caller puts together the RPC message, stuffs it into
+ * the request struct, and calls xprt_call().
+ * - xprt_call transmits the message and installs the caller on the
+ * socket's wait list. At the same time, it installs a timer that
+ * is run after the packet's timeout has expired.
+ * - When a packet arrives, the data_ready handler walks the list of
+ * pending requests for that socket. If a matching XID is found, the
+ * caller is woken up, and the timer removed.
+ * - When no reply arrives within the timeout interval, the timer is
+ * fired by the kernel and runs xprt_timer(). It either adjusts the
+ * timeout values (minor timeout) or wakes up the caller with a status
+ * of -ETIMEDOUT.
+ * - When the caller receives a notification from RPC that a reply arrived,
+ * it should release the RPC slot, and process the reply.
+ * If the call timed out, it may choose to retry the operation by
+ * adjusting the initial timeout value, and simply calling rpc_call
+ * again.
+ *
+ * Support for async RPC is done through a set of RPC-specific scheduling
+ * primitives that `transparently' work for processes as well as async
+ * tasks that rely on callbacks.
+ *
+ * Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
+ *
+ * TCP callback races fixes (C) 1998 Red Hat Software <alan@redhat.com>
+ * TCP send fixes (C) 1998 Red Hat Software <alan@redhat.com>
+ * TCP NFS related read + write fixes
+ * (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
+ *
+ * Rewrite of larges part of the code in order to stabilize TCP stuff.
+ * Fix behaviour when socket buffer is full.
+ * (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/capability.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/net.h>
+#include <linux/mm.h>
+#include <linux/udp.h>
+#include <linux/tcp.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/file.h>
+#include <linux/workqueue.h>
+#include <linux/random.h>
+
+#include <net/sock.h>
+#include <net/checksum.h>
+#include <net/udp.h>
+#include <net/tcp.h>
+
+/*
+ * Local variables
+ */
+
+#ifdef RPC_DEBUG
+# undef RPC_DEBUG_DATA
+# define RPCDBG_FACILITY RPCDBG_XPRT
+#endif
+
+#define XPRT_MAX_BACKOFF (8)
+#define XPRT_IDLE_TIMEOUT (5*60*HZ)
+#define XPRT_MAX_RESVPORT (800)
+
+/*
+ * Local functions
+ */
+static void xprt_request_init(struct rpc_task *, struct rpc_xprt *);
+static inline void do_xprt_reserve(struct rpc_task *);
+static void xprt_disconnect(struct rpc_xprt *);
+static void xprt_connect_status(struct rpc_task *task);
+static struct rpc_xprt * xprt_setup(int proto, struct sockaddr_in *ap,
+ struct rpc_timeout *to);
+static struct socket *xprt_create_socket(struct rpc_xprt *, int, int);
+static void xprt_bind_socket(struct rpc_xprt *, struct socket *);
+static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
+
+static int xprt_clear_backlog(struct rpc_xprt *xprt);
+
+#ifdef RPC_DEBUG_DATA
+/*
+ * Print the buffer contents (first 128 bytes only--just enough for
+ * diropres return).
+ */
+static void
+xprt_pktdump(char *msg, u32 *packet, unsigned int count)
+{
+ u8 *buf = (u8 *) packet;
+ int j;
+
+ dprintk("RPC: %s\n", msg);
+ for (j = 0; j < count && j < 128; j += 4) {
+ if (!(j & 31)) {
+ if (j)
+ dprintk("\n");
+ dprintk("0x%04x ", j);
+ }
+ dprintk("%02x%02x%02x%02x ",
+ buf[j], buf[j+1], buf[j+2], buf[j+3]);
+ }
+ dprintk("\n");
+}
+#else
+static inline void
+xprt_pktdump(char *msg, u32 *packet, unsigned int count)
+{
+ /* NOP */
+}
+#endif
+
+/*
+ * Look up RPC transport given an INET socket
+ */
+static inline struct rpc_xprt *
+xprt_from_sock(struct sock *sk)
+{
+ return (struct rpc_xprt *) sk->sk_user_data;
+}
+
+/*
+ * Serialize write access to sockets, in order to prevent different
+ * requests from interfering with each other.
+ * Also prevents TCP socket connects from colliding with writes.
+ */
+static int
+__xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+ struct rpc_rqst *req = task->tk_rqstp;
+
+ if (test_and_set_bit(XPRT_LOCKED, &xprt->sockstate)) {
+ if (task == xprt->snd_task)
+ return 1;
+ if (task == NULL)
+ return 0;
+ goto out_sleep;
+ }
+ if (xprt->nocong || __xprt_get_cong(xprt, task)) {
+ xprt->snd_task = task;
+ if (req) {
+ req->rq_bytes_sent = 0;
+ req->rq_ntrans++;
+ }
+ return 1;
+ }
+ smp_mb__before_clear_bit();
+ clear_bit(XPRT_LOCKED, &xprt->sockstate);
+ smp_mb__after_clear_bit();
+out_sleep:
+ dprintk("RPC: %4d failed to lock socket %p\n", task->tk_pid, xprt);
+ task->tk_timeout = 0;
+ task->tk_status = -EAGAIN;
+ if (req && req->rq_ntrans)
+ rpc_sleep_on(&xprt->resend, task, NULL, NULL);
+ else
+ rpc_sleep_on(&xprt->sending, task, NULL, NULL);
+ return 0;
+}
+
+static inline int
+xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+ int retval;
+
+ spin_lock_bh(&xprt->sock_lock);
+ retval = __xprt_lock_write(xprt, task);
+ spin_unlock_bh(&xprt->sock_lock);
+ return retval;
+}
+
+
+static void
+__xprt_lock_write_next(struct rpc_xprt *xprt)
+{
+ struct rpc_task *task;
+
+ if (test_and_set_bit(XPRT_LOCKED, &xprt->sockstate))
+ return;
+ if (!xprt->nocong && RPCXPRT_CONGESTED(xprt))
+ goto out_unlock;
+ task = rpc_wake_up_next(&xprt->resend);
+ if (!task) {
+ task = rpc_wake_up_next(&xprt->sending);
+ if (!task)
+ goto out_unlock;
+ }
+ if (xprt->nocong || __xprt_get_cong(xprt, task)) {
+ struct rpc_rqst *req = task->tk_rqstp;
+ xprt->snd_task = task;
+ if (req) {
+ req->rq_bytes_sent = 0;
+ req->rq_ntrans++;
+ }
+ return;
+ }
+out_unlock:
+ smp_mb__before_clear_bit();
+ clear_bit(XPRT_LOCKED, &xprt->sockstate);
+ smp_mb__after_clear_bit();
+}
+
+/*
+ * Releases the socket for use by other requests.
+ */
+static void
+__xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+ if (xprt->snd_task == task) {
+ xprt->snd_task = NULL;
+ smp_mb__before_clear_bit();
+ clear_bit(XPRT_LOCKED, &xprt->sockstate);
+ smp_mb__after_clear_bit();
+ __xprt_lock_write_next(xprt);
+ }
+}
+
+static inline void
+xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+ spin_lock_bh(&xprt->sock_lock);
+ __xprt_release_write(xprt, task);
+ spin_unlock_bh(&xprt->sock_lock);
+}
+
+/*
+ * Write data to socket.
+ */
+static inline int
+xprt_sendmsg(struct rpc_xprt *xprt, struct rpc_rqst *req)
+{
+ 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;
+
+ if (!sock)
+ return -ENOTCONN;
+
+ xprt_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);
+ }
+ /* Dont repeat bytes */
+ skip = req->rq_bytes_sent;
+
+ clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
+ result = xdr_sendpages(sock, addr, addrlen, xdr, skip, MSG_DONTWAIT);
+
+ dprintk("RPC: xprt_sendmsg(%d) = %d\n", xdr->len - skip, result);
+
+ if (result >= 0)
+ return result;
+
+ switch (result) {
+ 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;
+ break;
+ default:
+ printk(KERN_NOTICE "RPC: sendmsg returned error %d\n", -result);
+ }
+ return result;
+}
+
+/*
+ * Van Jacobson congestion avoidance. Check if the congestion window
+ * overflowed. Put the task to sleep if this is the case.
+ */
+static int
+__xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+ struct rpc_rqst *req = task->tk_rqstp;
+
+ if (req->rq_cong)
+ return 1;
+ dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n",
+ task->tk_pid, xprt->cong, xprt->cwnd);
+ if (RPCXPRT_CONGESTED(xprt))
+ return 0;
+ req->rq_cong = 1;
+ xprt->cong += RPC_CWNDSCALE;
+ return 1;
+}
+
+/*
+ * Adjust the congestion window, and wake up the next task
+ * that has been sleeping due to congestion
+ */
+static void
+__xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
+{
+ if (!req->rq_cong)
+ return;
+ req->rq_cong = 0;
+ xprt->cong -= RPC_CWNDSCALE;
+ __xprt_lock_write_next(xprt);
+}
+
+/*
+ * Adjust RPC congestion window
+ * We use a time-smoothed congestion estimator to avoid heavy oscillation.
+ */
+static void
+xprt_adjust_cwnd(struct rpc_xprt *xprt, int result)
+{
+ unsigned long cwnd;
+
+ cwnd = xprt->cwnd;
+ if (result >= 0 && cwnd <= xprt->cong) {
+ /* The (cwnd >> 1) term makes sure
+ * the result gets rounded properly. */
+ cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
+ if (cwnd > RPC_MAXCWND(xprt))
+ cwnd = RPC_MAXCWND(xprt);
+ __xprt_lock_write_next(xprt);
+ } else if (result == -ETIMEDOUT) {
+ cwnd >>= 1;
+ if (cwnd < RPC_CWNDSCALE)
+ cwnd = RPC_CWNDSCALE;
+ }
+ dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n",
+ xprt->cong, xprt->cwnd, cwnd);
+ xprt->cwnd = cwnd;
+}
+
+/*
+ * Reset the major timeout value
+ */
+static void xprt_reset_majortimeo(struct rpc_rqst *req)
+{
+ struct rpc_timeout *to = &req->rq_xprt->timeout;
+
+ req->rq_majortimeo = req->rq_timeout;
+ if (to->to_exponential)
+ req->rq_majortimeo <<= to->to_retries;
+ else
+ req->rq_majortimeo += to->to_increment * to->to_retries;
+ if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0)
+ req->rq_majortimeo = to->to_maxval;
+ req->rq_majortimeo += jiffies;
+}
+
+/*
+ * Adjust timeout values etc for next retransmit
+ */
+int xprt_adjust_timeout(struct rpc_rqst *req)
+{
+ struct rpc_xprt *xprt = req->rq_xprt;
+ struct rpc_timeout *to = &xprt->timeout;
+ int status = 0;
+
+ if (time_before(jiffies, req->rq_majortimeo)) {
+ if (to->to_exponential)
+ req->rq_timeout <<= 1;
+ else
+ req->rq_timeout += to->to_increment;
+ if (to->to_maxval && req->rq_timeout >= to->to_maxval)
+ req->rq_timeout = to->to_maxval;
+ req->rq_retries++;
+ pprintk("RPC: %lu retrans\n", jiffies);
+ } else {
+ req->rq_timeout = to->to_initval;
+ req->rq_retries = 0;
+ xprt_reset_majortimeo(req);
+ /* Reset the RTT counters == "slow start" */
+ spin_lock_bh(&xprt->sock_lock);
+ rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
+ spin_unlock_bh(&xprt->sock_lock);
+ pprintk("RPC: %lu timeout\n", jiffies);
+ status = -ETIMEDOUT;
+ }
+
+ if (req->rq_timeout == 0) {
+ printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n");
+ req->rq_timeout = 5 * HZ;
+ }
+ return status;
+}
+
+/*
+ * Close down a transport socket
+ */
+static void
+xprt_close(struct rpc_xprt *xprt)
+{
+ struct socket *sock = xprt->sock;
+ struct sock *sk = xprt->inet;
+
+ if (!sk)
+ return;
+
+ write_lock_bh(&sk->sk_callback_lock);
+ xprt->inet = NULL;
+ xprt->sock = NULL;
+
+ sk->sk_user_data = NULL;
+ sk->sk_data_ready = xprt->old_data_ready;
+ sk->sk_state_change = xprt->old_state_change;
+ sk->sk_write_space = xprt->old_write_space;
+ write_unlock_bh(&sk->sk_callback_lock);
+
+ sk->sk_no_check = 0;
+
+ sock_release(sock);
+}
+
+static void
+xprt_socket_autoclose(void *args)
+{
+ struct rpc_xprt *xprt = (struct rpc_xprt *)args;
+
+ xprt_disconnect(xprt);
+ xprt_close(xprt);
+ xprt_release_write(xprt, NULL);
+}
+
+/*
+ * Mark a transport as disconnected
+ */
+static void
+xprt_disconnect(struct rpc_xprt *xprt)
+{
+ dprintk("RPC: disconnected transport %p\n", xprt);
+ spin_lock_bh(&xprt->sock_lock);
+ xprt_clear_connected(xprt);
+ rpc_wake_up_status(&xprt->pending, -ENOTCONN);
+ spin_unlock_bh(&xprt->sock_lock);
+}
+
+/*
+ * Used to allow disconnection when we've been idle
+ */
+static void
+xprt_init_autodisconnect(unsigned long data)
+{
+ struct rpc_xprt *xprt = (struct rpc_xprt *)data;
+
+ spin_lock(&xprt->sock_lock);
+ if (!list_empty(&xprt->recv) || xprt->shutdown)
+ goto out_abort;
+ if (test_and_set_bit(XPRT_LOCKED, &xprt->sockstate))
+ goto out_abort;
+ spin_unlock(&xprt->sock_lock);
+ /* Let keventd close the socket */
+ if (test_bit(XPRT_CONNECTING, &xprt->sockstate) != 0)
+ xprt_release_write(xprt, NULL);
+ else
+ schedule_work(&xprt->task_cleanup);
+ return;
+out_abort:
+ spin_unlock(&xprt->sock_lock);
+}
+
+static void xprt_socket_connect(void *args)
+{
+ struct rpc_xprt *xprt = (struct rpc_xprt *)args;
+ struct socket *sock = xprt->sock;
+ int status = -EIO;
+
+ if (xprt->shutdown || xprt->addr.sin_port == 0)
+ goto out;
+
+ /*
+ * Start by resetting any existing state
+ */
+ xprt_close(xprt);
+ sock = xprt_create_socket(xprt, xprt->prot, xprt->resvport);
+ if (sock == NULL) {
+ /* couldn't create socket or bind to reserved port;
+ * this is likely a permanent error, so cause an abort */
+ goto out;
+ }
+ xprt_bind_socket(xprt, sock);
+ xprt_sock_setbufsize(xprt);
+
+ status = 0;
+ if (!xprt->stream)
+ goto out;
+
+ /*
+ * Tell the socket layer to start connecting...
+ */
+ status = sock->ops->connect(sock, (struct sockaddr *) &xprt->addr,
+ sizeof(xprt->addr), O_NONBLOCK);
+ dprintk("RPC: %p connect status %d connected %d sock state %d\n",
+ xprt, -status, xprt_connected(xprt), sock->sk->sk_state);
+ if (status < 0) {
+ switch (status) {
+ case -EINPROGRESS:
+ case -EALREADY:
+ goto out_clear;
+ }
+ }
+out:
+ if (status < 0)
+ rpc_wake_up_status(&xprt->pending, status);
+ else
+ rpc_wake_up(&xprt->pending);
+out_clear:
+ smp_mb__before_clear_bit();
+ clear_bit(XPRT_CONNECTING, &xprt->sockstate);
+ smp_mb__after_clear_bit();
+}
+
+/*
+ * Attempt to connect a TCP socket.
+ *
+ */
+void xprt_connect(struct rpc_task *task)
+{
+ struct rpc_xprt *xprt = task->tk_xprt;
+
+ dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid,
+ xprt, (xprt_connected(xprt) ? "is" : "is not"));
+
+ if (xprt->shutdown) {
+ task->tk_status = -EIO;
+ return;
+ }
+ if (!xprt->addr.sin_port) {
+ task->tk_status = -EIO;
+ return;
+ }
+ if (!xprt_lock_write(xprt, task))
+ return;
+ if (xprt_connected(xprt))
+ goto out_write;
+
+ if (task->tk_rqstp)
+ task->tk_rqstp->rq_bytes_sent = 0;
+
+ task->tk_timeout = RPC_CONNECT_TIMEOUT;
+ rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL);
+ if (!test_and_set_bit(XPRT_CONNECTING, &xprt->sockstate)) {
+ /* Note: if we are here due to a dropped connection
+ * we delay reconnecting by RPC_REESTABLISH_TIMEOUT/HZ
+ * seconds
+ */
+ if (xprt->sock != NULL)
+ schedule_delayed_work(&xprt->sock_connect,
+ RPC_REESTABLISH_TIMEOUT);
+ else
+ schedule_work(&xprt->sock_connect);
+ }
+ return;
+ out_write:
+ xprt_release_write(xprt, task);
+}
+
+/*
+ * We arrive here when awoken from waiting on connection establishment.
+ */
+static void
+xprt_connect_status(struct rpc_task *task)
+{
+ struct rpc_xprt *xprt = task->tk_xprt;
+
+ if (task->tk_status >= 0) {
+ dprintk("RPC: %4d xprt_connect_status: connection established\n",
+ task->tk_pid);
+ return;
+ }
+
+ /* if soft mounted, just cause this RPC to fail */
+ if (RPC_IS_SOFT(task))
+ task->tk_status = -EIO;
+
+ switch (task->tk_status) {
+ case -ECONNREFUSED:
+ case -ECONNRESET:
+ case -ENOTCONN:
+ return;
+ case -ETIMEDOUT:
+ dprintk("RPC: %4d xprt_connect_status: timed out\n",
+ task->tk_pid);
+ break;
+ default:
+ printk(KERN_ERR "RPC: error %d connecting to server %s\n",
+ -task->tk_status, task->tk_client->cl_server);
+ }
+ xprt_release_write(xprt, task);
+}
+
+/*
+ * Look up the RPC request corresponding to a reply, and then lock it.
+ */
+static inline struct rpc_rqst *
+xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid)
+{
+ struct list_head *pos;
+ struct rpc_rqst *req = NULL;
+
+ list_for_each(pos, &xprt->recv) {
+ struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list);
+ if (entry->rq_xid == xid) {
+ req = entry;
+ break;
+ }
+ }
+ return req;
+}
+
+/*
+ * Complete reply received.
+ * The TCP code relies on us to remove the request from xprt->pending.
+ */
+static void
+xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
+{
+ struct rpc_task *task = req->rq_task;
+ struct rpc_clnt *clnt = task->tk_client;
+
+ /* Adjust congestion window */
+ if (!xprt->nocong) {
+ unsigned timer = task->tk_msg.rpc_proc->p_timer;
+ xprt_adjust_cwnd(xprt, copied);
+ __xprt_put_cong(xprt, req);
+ if (timer) {
+ if (req->rq_ntrans == 1)
+ rpc_update_rtt(clnt->cl_rtt, timer,
+ (long)jiffies - req->rq_xtime);
+ rpc_set_timeo(clnt->cl_rtt, timer, req->rq_ntrans - 1);
+ }
+ }
+
+#ifdef RPC_PROFILE
+ /* Profile only reads for now */
+ if (copied > 1024) {
+ static unsigned long nextstat;
+ static unsigned long pkt_rtt, pkt_len, pkt_cnt;
+
+ pkt_cnt++;
+ pkt_len += req->rq_slen + copied;
+ pkt_rtt += jiffies - req->rq_xtime;
+ if (time_before(nextstat, jiffies)) {
+ printk("RPC: %lu %ld cwnd\n", jiffies, xprt->cwnd);
+ printk("RPC: %ld %ld %ld %ld stat\n",
+ jiffies, pkt_cnt, pkt_len, pkt_rtt);
+ pkt_rtt = pkt_len = pkt_cnt = 0;
+ nextstat = jiffies + 5 * HZ;
+ }
+ }
+#endif
+
+ dprintk("RPC: %4d has input (%d bytes)\n", task->tk_pid, copied);
+ list_del_init(&req->rq_list);
+ req->rq_received = req->rq_private_buf.len = copied;
+
+ /* ... and wake up the process. */
+ rpc_wake_up_task(task);
+ return;
+}
+
+static size_t
+skb_read_bits(skb_reader_t *desc, void *to, size_t len)
+{
+ if (len > desc->count)
+ len = desc->count;
+ if (skb_copy_bits(desc->skb, desc->offset, to, len))
+ return 0;
+ desc->count -= len;
+ desc->offset += len;
+ return len;
+}
+
+static size_t
+skb_read_and_csum_bits(skb_reader_t *desc, void *to, size_t len)
+{
+ unsigned int csum2, pos;
+
+ if (len > desc->count)
+ len = desc->count;
+ pos = desc->offset;
+ csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
+ desc->csum = csum_block_add(desc->csum, csum2, pos);
+ desc->count -= len;
+ desc->offset += len;
+ return len;
+}
+
+/*
+ * We have set things up such that we perform the checksum of the UDP
+ * packet in parallel with the copies into the RPC client iovec. -DaveM
+ */
+int
+csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
+{
+ skb_reader_t desc;
+
+ desc.skb = skb;
+ desc.offset = sizeof(struct udphdr);
+ desc.count = skb->len - desc.offset;
+
+ if (skb->ip_summed == CHECKSUM_UNNECESSARY)
+ goto no_checksum;
+
+ desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
+ xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_and_csum_bits);
+ if (desc.offset != skb->len) {
+ unsigned int csum2;
+ csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
+ desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
+ }
+ if (desc.count)
+ return -1;
+ if ((unsigned short)csum_fold(desc.csum))
+ return -1;
+ return 0;
+no_checksum:
+ xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_bits);
+ if (desc.count)
+ return -1;
+ return 0;
+}
+
+/*
+ * Input handler for RPC replies. Called from a bottom half and hence
+ * atomic.
+ */
+static void
+udp_data_ready(struct sock *sk, int len)
+{
+ struct rpc_task *task;
+ struct rpc_xprt *xprt;
+ struct rpc_rqst *rovr;
+ struct sk_buff *skb;
+ int err, repsize, copied;
+ u32 _xid, *xp;
+
+ read_lock(&sk->sk_callback_lock);
+ dprintk("RPC: udp_data_ready...\n");
+ if (!(xprt = xprt_from_sock(sk))) {
+ printk("RPC: udp_data_ready request not found!\n");
+ goto out;
+ }
+
+ dprintk("RPC: udp_data_ready client %p\n", xprt);
+
+ if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
+ goto out;
+
+ if (xprt->shutdown)
+ goto dropit;
+
+ repsize = skb->len - sizeof(struct udphdr);
+ if (repsize < 4) {
+ printk("RPC: impossible RPC reply size %d!\n", repsize);
+ goto dropit;
+ }
+
+ /* Copy the XID from the skb... */
+ xp = skb_header_pointer(skb, sizeof(struct udphdr),
+ sizeof(_xid), &_xid);
+ if (xp == NULL)
+ goto dropit;
+
+ /* Look up and lock the request corresponding to the given XID */
+ spin_lock(&xprt->sock_lock);
+ rovr = xprt_lookup_rqst(xprt, *xp);
+ if (!rovr)
+ goto out_unlock;
+ task = rovr->rq_task;
+
+ dprintk("RPC: %4d received reply\n", task->tk_pid);
+
+ if ((copied = rovr->rq_private_buf.buflen) > repsize)
+ copied = repsize;
+
+ /* Suck it into the iovec, verify checksum if not done by hw. */
+ if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb))
+ goto out_unlock;
+
+ /* Something worked... */
+ dst_confirm(skb->dst);
+
+ xprt_complete_rqst(xprt, rovr, copied);
+
+ out_unlock:
+ spin_unlock(&xprt->sock_lock);
+ dropit:
+ skb_free_datagram(sk, skb);
+ out:
+ read_unlock(&sk->sk_callback_lock);
+}
+
+/*
+ * Copy from an skb into memory and shrink the skb.
+ */
+static inline size_t
+tcp_copy_data(skb_reader_t *desc, void *p, size_t len)
+{
+ if (len > desc->count)
+ len = desc->count;
+ if (skb_copy_bits(desc->skb, desc->offset, p, len))
+ return 0;
+ desc->offset += len;
+ desc->count -= len;
+ return len;
+}
+
+/*
+ * TCP read fragment marker
+ */
+static inline void
+tcp_read_fraghdr(struct rpc_xprt *xprt, skb_reader_t *desc)
+{
+ size_t len, used;
+ char *p;
+
+ p = ((char *) &xprt->tcp_recm) + xprt->tcp_offset;
+ len = sizeof(xprt->tcp_recm) - xprt->tcp_offset;
+ used = tcp_copy_data(desc, p, len);
+ xprt->tcp_offset += used;
+ if (used != len)
+ return;
+ xprt->tcp_reclen = ntohl(xprt->tcp_recm);
+ if (xprt->tcp_reclen & 0x80000000)
+ xprt->tcp_flags |= XPRT_LAST_FRAG;
+ else
+ xprt->tcp_flags &= ~XPRT_LAST_FRAG;
+ xprt->tcp_reclen &= 0x7fffffff;
+ xprt->tcp_flags &= ~XPRT_COPY_RECM;
+ xprt->tcp_offset = 0;
+ /* Sanity check of the record length */
+ if (xprt->tcp_reclen < 4) {
+ printk(KERN_ERR "RPC: Invalid TCP record fragment length\n");
+ xprt_disconnect(xprt);
+ }
+ dprintk("RPC: reading TCP record fragment of length %d\n",
+ xprt->tcp_reclen);
+}
+
+static void
+tcp_check_recm(struct rpc_xprt *xprt)
+{
+ if (xprt->tcp_offset == xprt->tcp_reclen) {
+ xprt->tcp_flags |= XPRT_COPY_RECM;
+ xprt->tcp_offset = 0;
+ if (xprt->tcp_flags & XPRT_LAST_FRAG) {
+ xprt->tcp_flags &= ~XPRT_COPY_DATA;
+ xprt->tcp_flags |= XPRT_COPY_XID;
+ xprt->tcp_copied = 0;
+ }
+ }
+}
+
+/*
+ * TCP read xid
+ */
+static inline void
+tcp_read_xid(struct rpc_xprt *xprt, skb_reader_t *desc)
+{
+ size_t len, used;
+ char *p;
+
+ len = sizeof(xprt->tcp_xid) - xprt->tcp_offset;
+ dprintk("RPC: reading XID (%Zu bytes)\n", len);
+ p = ((char *) &xprt->tcp_xid) + xprt->tcp_offset;
+ used = tcp_copy_data(desc, p, len);
+ xprt->tcp_offset += used;
+ if (used != len)
+ return;
+ xprt->tcp_flags &= ~XPRT_COPY_XID;
+ xprt->tcp_flags |= XPRT_COPY_DATA;
+ xprt->tcp_copied = 4;
+ dprintk("RPC: reading reply for XID %08x\n",
+ ntohl(xprt->tcp_xid));
+ tcp_check_recm(xprt);
+}
+
+/*
+ * TCP read and complete request
+ */
+static inline void
+tcp_read_request(struct rpc_xprt *xprt, skb_reader_t *desc)
+{
+ struct rpc_rqst *req;
+ struct xdr_buf *rcvbuf;
+ size_t len;
+
+ /* Find and lock the request corresponding to this xid */
+ spin_lock(&xprt->sock_lock);
+ req = xprt_lookup_rqst(xprt, xprt->tcp_xid);
+ if (!req) {
+ xprt->tcp_flags &= ~XPRT_COPY_DATA;
+ dprintk("RPC: XID %08x request not found!\n",
+ ntohl(xprt->tcp_xid));
+ spin_unlock(&xprt->sock_lock);
+ return;
+ }
+
+ rcvbuf = &req->rq_private_buf;
+ len = desc->count;
+ if (len > xprt->tcp_reclen - xprt->tcp_offset) {
+ skb_reader_t my_desc;
+
+ len = xprt->tcp_reclen - xprt->tcp_offset;
+ memcpy(&my_desc, desc, sizeof(my_desc));
+ my_desc.count = len;
+ xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
+ &my_desc, tcp_copy_data);
+ desc->count -= len;
+ desc->offset += len;
+ } else
+ xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
+ desc, tcp_copy_data);
+ xprt->tcp_copied += len;
+ xprt->tcp_offset += len;
+
+ if (xprt->tcp_copied == req->rq_private_buf.buflen)
+ xprt->tcp_flags &= ~XPRT_COPY_DATA;
+ else if (xprt->tcp_offset == xprt->tcp_reclen) {
+ if (xprt->tcp_flags & XPRT_LAST_FRAG)
+ xprt->tcp_flags &= ~XPRT_COPY_DATA;
+ }
+
+ if (!(xprt->tcp_flags & XPRT_COPY_DATA)) {
+ dprintk("RPC: %4d received reply complete\n",
+ req->rq_task->tk_pid);
+ xprt_complete_rqst(xprt, req, xprt->tcp_copied);
+ }
+ spin_unlock(&xprt->sock_lock);
+ tcp_check_recm(xprt);
+}
+
+/*
+ * TCP discard extra bytes from a short read
+ */
+static inline void
+tcp_read_discard(struct rpc_xprt *xprt, skb_reader_t *desc)
+{
+ size_t len;
+
+ len = xprt->tcp_reclen - xprt->tcp_offset;
+ if (len > desc->count)
+ len = desc->count;
+ desc->count -= len;
+ desc->offset += len;
+ xprt->tcp_offset += len;
+ tcp_check_recm(xprt);
+}
+
+/*
+ * TCP record receive routine
+ * We first have to grab the record marker, then the XID, then the data.
+ */
+static int
+tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
+ unsigned int offset, size_t len)
+{
+ struct rpc_xprt *xprt = rd_desc->arg.data;
+ skb_reader_t desc = {
+ .skb = skb,
+ .offset = offset,
+ .count = len,
+ .csum = 0
+ };
+
+ dprintk("RPC: tcp_data_recv\n");
+ do {
+ /* Read in a new fragment marker if necessary */
+ /* Can we ever really expect to get completely empty fragments? */
+ if (xprt->tcp_flags & XPRT_COPY_RECM) {
+ tcp_read_fraghdr(xprt, &desc);
+ continue;
+ }
+ /* Read in the xid if necessary */
+ if (xprt->tcp_flags & XPRT_COPY_XID) {
+ tcp_read_xid(xprt, &desc);
+ continue;
+ }
+ /* Read in the request data */
+ if (xprt->tcp_flags & XPRT_COPY_DATA) {
+ tcp_read_request(xprt, &desc);
+ continue;
+ }
+ /* Skip over any trailing bytes on short reads */
+ tcp_read_discard(xprt, &desc);
+ } while (desc.count);
+ dprintk("RPC: tcp_data_recv done\n");
+ return len - desc.count;
+}
+
+static void tcp_data_ready(struct sock *sk, int bytes)
+{
+ struct rpc_xprt *xprt;
+ read_descriptor_t rd_desc;
+
+ read_lock(&sk->sk_callback_lock);
+ dprintk("RPC: tcp_data_ready...\n");
+ if (!(xprt = xprt_from_sock(sk))) {
+ printk("RPC: tcp_data_ready socket info not found!\n");
+ goto out;
+ }
+ if (xprt->shutdown)
+ goto out;
+
+ /* We use rd_desc to pass struct xprt to tcp_data_recv */
+ rd_desc.arg.data = xprt;
+ rd_desc.count = 65536;
+ tcp_read_sock(sk, &rd_desc, tcp_data_recv);
+out:
+ read_unlock(&sk->sk_callback_lock);
+}
+
+static void
+tcp_state_change(struct sock *sk)
+{
+ struct rpc_xprt *xprt;
+
+ read_lock(&sk->sk_callback_lock);
+ if (!(xprt = xprt_from_sock(sk)))
+ goto out;
+ dprintk("RPC: tcp_state_change client %p...\n", xprt);
+ dprintk("RPC: state %x conn %d dead %d zapped %d\n",
+ sk->sk_state, xprt_connected(xprt),
+ sock_flag(sk, SOCK_DEAD),
+ sock_flag(sk, SOCK_ZAPPED));
+
+ switch (sk->sk_state) {
+ case TCP_ESTABLISHED:
+ spin_lock_bh(&xprt->sock_lock);
+ if (!xprt_test_and_set_connected(xprt)) {
+ /* Reset TCP record info */
+ xprt->tcp_offset = 0;
+ xprt->tcp_reclen = 0;
+ xprt->tcp_copied = 0;
+ xprt->tcp_flags = XPRT_COPY_RECM | XPRT_COPY_XID;
+ rpc_wake_up(&xprt->pending);
+ }
+ spin_unlock_bh(&xprt->sock_lock);
+ break;
+ case TCP_SYN_SENT:
+ case TCP_SYN_RECV:
+ break;
+ default:
+ if (xprt_test_and_clear_connected(xprt))
+ rpc_wake_up_status(&xprt->pending, -ENOTCONN);
+ break;
+ }
+ out:
+ read_unlock(&sk->sk_callback_lock);
+}
+
+/*
+ * Called when more output buffer space is available for this socket.
+ * We try not to wake our writers until they can make "significant"
+ * progress, otherwise we'll waste resources thrashing sock_sendmsg
+ * with a bunch of small requests.
+ */
+static void
+xprt_write_space(struct sock *sk)
+{
+ struct rpc_xprt *xprt;
+ struct socket *sock;
+
+ read_lock(&sk->sk_callback_lock);
+ if (!(xprt = xprt_from_sock(sk)) || !(sock = sk->sk_socket))
+ goto out;
+ if (xprt->shutdown)
+ goto out;
+
+ /* Wait until we have enough socket memory */
+ if (xprt->stream) {
+ /* from net/core/stream.c:sk_stream_write_space */
+ if (sk_stream_wspace(sk) < sk_stream_min_wspace(sk))
+ goto out;
+ } else {
+ /* from net/core/sock.c:sock_def_write_space */
+ if (!sock_writeable(sk))
+ goto out;
+ }
+
+ if (!test_and_clear_bit(SOCK_NOSPACE, &sock->flags))
+ goto out;
+
+ spin_lock_bh(&xprt->sock_lock);
+ if (xprt->snd_task)
+ rpc_wake_up_task(xprt->snd_task);
+ spin_unlock_bh(&xprt->sock_lock);
+out:
+ read_unlock(&sk->sk_callback_lock);
+}
+
+/*
+ * RPC receive timeout handler.
+ */
+static void
+xprt_timer(struct rpc_task *task)
+{
+ struct rpc_rqst *req = task->tk_rqstp;
+ struct rpc_xprt *xprt = req->rq_xprt;
+
+ spin_lock(&xprt->sock_lock);
+ if (req->rq_received)
+ goto out;
+
+ xprt_adjust_cwnd(req->rq_xprt, -ETIMEDOUT);
+ __xprt_put_cong(xprt, req);
+
+ dprintk("RPC: %4d xprt_timer (%s request)\n",
+ task->tk_pid, req ? "pending" : "backlogged");
+
+ task->tk_status = -ETIMEDOUT;
+out:
+ task->tk_timeout = 0;
+ rpc_wake_up_task(task);
+ spin_unlock(&xprt->sock_lock);
+}
+
+/*
+ * Place the actual RPC call.
+ * We have to copy the iovec because sendmsg fiddles with its contents.
+ */
+int
+xprt_prepare_transmit(struct rpc_task *task)
+{
+ struct rpc_rqst *req = task->tk_rqstp;
+ struct rpc_xprt *xprt = req->rq_xprt;
+ int err = 0;
+
+ dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid);
+
+ if (xprt->shutdown)
+ return -EIO;
+
+ spin_lock_bh(&xprt->sock_lock);
+ if (req->rq_received && !req->rq_bytes_sent) {
+ err = req->rq_received;
+ goto out_unlock;
+ }
+ if (!__xprt_lock_write(xprt, task)) {
+ err = -EAGAIN;
+ goto out_unlock;
+ }
+
+ if (!xprt_connected(xprt)) {
+ err = -ENOTCONN;
+ goto out_unlock;
+ }
+out_unlock:
+ spin_unlock_bh(&xprt->sock_lock);
+ return err;
+}
+
+void
+xprt_transmit(struct rpc_task *task)
+{
+ struct rpc_clnt *clnt = task->tk_client;
+ struct rpc_rqst *req = task->tk_rqstp;
+ struct rpc_xprt *xprt = req->rq_xprt;
+ int status, retry = 0;
+
+
+ dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
+
+ /* 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)));
+ }
+
+ smp_rmb();
+ if (!req->rq_received) {
+ if (list_empty(&req->rq_list)) {
+ spin_lock_bh(&xprt->sock_lock);
+ /* Update the softirq receive buffer */
+ memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
+ sizeof(req->rq_private_buf));
+ /* Add request to the receive list */
+ list_add_tail(&req->rq_list, &xprt->recv);
+ spin_unlock_bh(&xprt->sock_lock);
+ xprt_reset_majortimeo(req);
+ }
+ } else if (!req->rq_bytes_sent)
+ return;
+
+ /* Continue transmitting the packet/record. We must be careful
+ * to cope with writespace callbacks arriving _after_ we have
+ * called xprt_sendmsg().
+ */
+ while (1) {
+ req->rq_xtime = jiffies;
+ status = xprt_sendmsg(xprt, req);
+
+ if (status < 0)
+ break;
+
+ if (xprt->stream) {
+ req->rq_bytes_sent += status;
+
+ /* 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 = 0;
+ goto out_receive;
+ }
+ } else {
+ if (status >= req->rq_slen)
+ goto out_receive;
+ status = -EAGAIN;
+ 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)
+ break;
+ }
+
+ /* Note: at this point, task->tk_sleeping has not yet been set,
+ * hence there is no danger of the waking up task being put on
+ * schedq, and being picked up by a parallel run of rpciod().
+ */
+ task->tk_status = status;
+
+ switch (status) {
+ case -EAGAIN:
+ if (test_bit(SOCK_ASYNC_NOSPACE, &xprt->sock->flags)) {
+ /* Protect against races with xprt_write_space */
+ spin_lock_bh(&xprt->sock_lock);
+ /* Don't race with disconnect */
+ if (!xprt_connected(xprt))
+ task->tk_status = -ENOTCONN;
+ else if (test_bit(SOCK_NOSPACE, &xprt->sock->flags)) {
+ task->tk_timeout = req->rq_timeout;
+ rpc_sleep_on(&xprt->pending, task, NULL, NULL);
+ }
+ spin_unlock_bh(&xprt->sock_lock);
+ return;
+ }
+ /* Keep holding the socket if it is blocked */
+ rpc_delay(task, HZ>>4);
+ return;
+ case -ECONNREFUSED:
+ task->tk_timeout = RPC_REESTABLISH_TIMEOUT;
+ rpc_sleep_on(&xprt->sending, task, NULL, NULL);
+ case -ENOTCONN:
+ return;
+ default:
+ if (xprt->stream)
+ xprt_disconnect(xprt);
+ }
+ xprt_release_write(xprt, task);
+ return;
+ out_receive:
+ dprintk("RPC: %4d xmit complete\n", task->tk_pid);
+ /* Set the task's receive timeout value */
+ spin_lock_bh(&xprt->sock_lock);
+ if (!xprt->nocong) {
+ int timer = task->tk_msg.rpc_proc->p_timer;
+ task->tk_timeout = rpc_calc_rto(clnt->cl_rtt, timer);
+ task->tk_timeout <<= rpc_ntimeo(clnt->cl_rtt, timer) + req->rq_retries;
+ if (task->tk_timeout > xprt->timeout.to_maxval || task->tk_timeout == 0)
+ task->tk_timeout = xprt->timeout.to_maxval;
+ } else
+ task->tk_timeout = req->rq_timeout;
+ /* Don't race with disconnect */
+ if (!xprt_connected(xprt))
+ task->tk_status = -ENOTCONN;
+ else if (!req->rq_received)
+ rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);
+ __xprt_release_write(xprt, task);
+ spin_unlock_bh(&xprt->sock_lock);
+}
+
+/*
+ * Reserve an RPC call slot.
+ */
+static inline void
+do_xprt_reserve(struct rpc_task *task)
+{
+ struct rpc_xprt *xprt = task->tk_xprt;
+
+ task->tk_status = 0;
+ if (task->tk_rqstp)
+ return;
+ if (!list_empty(&xprt->free)) {
+ struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
+ list_del_init(&req->rq_list);
+ task->tk_rqstp = req;
+ xprt_request_init(task, xprt);
+ return;
+ }
+ dprintk("RPC: waiting for request slot\n");
+ task->tk_status = -EAGAIN;
+ task->tk_timeout = 0;
+ rpc_sleep_on(&xprt->backlog, task, NULL, NULL);
+}
+
+void
+xprt_reserve(struct rpc_task *task)
+{
+ struct rpc_xprt *xprt = task->tk_xprt;
+
+ task->tk_status = -EIO;
+ if (!xprt->shutdown) {
+ spin_lock(&xprt->xprt_lock);
+ do_xprt_reserve(task);
+ spin_unlock(&xprt->xprt_lock);
+ if (task->tk_rqstp)
+ del_timer_sync(&xprt->timer);
+ }
+}
+
+/*
+ * Allocate a 'unique' XID
+ */
+static inline u32 xprt_alloc_xid(struct rpc_xprt *xprt)
+{
+ return xprt->xid++;
+}
+
+static inline void xprt_init_xid(struct rpc_xprt *xprt)
+{
+ get_random_bytes(&xprt->xid, sizeof(xprt->xid));
+}
+
+/*
+ * Initialize RPC request
+ */
+static void
+xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
+{
+ struct rpc_rqst *req = task->tk_rqstp;
+
+ req->rq_timeout = xprt->timeout.to_initval;
+ req->rq_task = task;
+ req->rq_xprt = xprt;
+ req->rq_xid = xprt_alloc_xid(xprt);
+ dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
+ req, ntohl(req->rq_xid));
+}
+
+/*
+ * Release an RPC call slot
+ */
+void
+xprt_release(struct rpc_task *task)
+{
+ struct rpc_xprt *xprt = task->tk_xprt;
+ struct rpc_rqst *req;
+
+ if (!(req = task->tk_rqstp))
+ return;
+ spin_lock_bh(&xprt->sock_lock);
+ __xprt_release_write(xprt, task);
+ __xprt_put_cong(xprt, req);
+ if (!list_empty(&req->rq_list))
+ list_del(&req->rq_list);
+ xprt->last_used = jiffies;
+ if (list_empty(&xprt->recv) && !xprt->shutdown)
+ mod_timer(&xprt->timer, xprt->last_used + XPRT_IDLE_TIMEOUT);
+ spin_unlock_bh(&xprt->sock_lock);
+ task->tk_rqstp = NULL;
+ memset(req, 0, sizeof(*req)); /* mark unused */
+
+ dprintk("RPC: %4d release request %p\n", task->tk_pid, req);
+
+ spin_lock(&xprt->xprt_lock);
+ list_add(&req->rq_list, &xprt->free);
+ xprt_clear_backlog(xprt);
+ spin_unlock(&xprt->xprt_lock);
+}
+
+/*
+ * Set default timeout parameters
+ */
+static void
+xprt_default_timeout(struct rpc_timeout *to, int proto)
+{
+ if (proto == IPPROTO_UDP)
+ xprt_set_timeout(to, 5, 5 * HZ);
+ else
+ xprt_set_timeout(to, 5, 60 * HZ);
+}
+
+/*
+ * Set constant timeout
+ */
+void
+xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr)
+{
+ to->to_initval =
+ to->to_increment = incr;
+ to->to_maxval = incr * retr;
+ to->to_retries = retr;
+ to->to_exponential = 0;
+}
+
+unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
+unsigned int xprt_tcp_slot_table_entries = RPC_DEF_SLOT_TABLE;
+
+/*
+ * Initialize an RPC client
+ */
+static struct rpc_xprt *
+xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to)
+{
+ struct rpc_xprt *xprt;
+ unsigned int entries;
+ size_t slot_table_size;
+ struct rpc_rqst *req;
+
+ dprintk("RPC: setting up %s transport...\n",
+ proto == IPPROTO_UDP? "UDP" : "TCP");
+
+ entries = (proto == IPPROTO_TCP)?
+ xprt_tcp_slot_table_entries : xprt_udp_slot_table_entries;
+
+ if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL)
+ return ERR_PTR(-ENOMEM);
+ memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */
+ xprt->max_reqs = entries;
+ slot_table_size = entries * sizeof(xprt->slot[0]);
+ xprt->slot = kmalloc(slot_table_size, GFP_KERNEL);
+ if (xprt->slot == NULL) {
+ kfree(xprt);
+ return ERR_PTR(-ENOMEM);
+ }
+ memset(xprt->slot, 0, slot_table_size);
+
+ xprt->addr = *ap;
+ xprt->prot = proto;
+ xprt->stream = (proto == IPPROTO_TCP)? 1 : 0;
+ if (xprt->stream) {
+ xprt->cwnd = RPC_MAXCWND(xprt);
+ xprt->nocong = 1;
+ xprt->max_payload = (1U << 31) - 1;
+ } else {
+ xprt->cwnd = RPC_INITCWND;
+ xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
+ }
+ spin_lock_init(&xprt->sock_lock);
+ spin_lock_init(&xprt->xprt_lock);
+ init_waitqueue_head(&xprt->cong_wait);
+
+ INIT_LIST_HEAD(&xprt->free);
+ INIT_LIST_HEAD(&xprt->recv);
+ INIT_WORK(&xprt->sock_connect, xprt_socket_connect, xprt);
+ INIT_WORK(&xprt->task_cleanup, xprt_socket_autoclose, xprt);
+ init_timer(&xprt->timer);
+ xprt->timer.function = xprt_init_autodisconnect;
+ xprt->timer.data = (unsigned long) xprt;
+ xprt->last_used = jiffies;
+ xprt->port = XPRT_MAX_RESVPORT;
+
+ /* Set timeout parameters */
+ if (to) {
+ xprt->timeout = *to;
+ } else
+ xprt_default_timeout(&xprt->timeout, xprt->prot);
+
+ rpc_init_wait_queue(&xprt->pending, "xprt_pending");
+ rpc_init_wait_queue(&xprt->sending, "xprt_sending");
+ rpc_init_wait_queue(&xprt->resend, "xprt_resend");
+ rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
+
+ /* initialize free list */
+ for (req = &xprt->slot[entries-1]; req >= &xprt->slot[0]; req--)
+ list_add(&req->rq_list, &xprt->free);
+
+ xprt_init_xid(xprt);
+
+ /* Check whether we want to use a reserved port */
+ xprt->resvport = capable(CAP_NET_BIND_SERVICE) ? 1 : 0;
+
+ dprintk("RPC: created transport %p with %u slots\n", xprt,
+ xprt->max_reqs);
+
+ return xprt;
+}
+
+/*
+ * Bind to a reserved port
+ */
+static inline int xprt_bindresvport(struct rpc_xprt *xprt, struct socket *sock)
+{
+ struct sockaddr_in myaddr = {
+ .sin_family = AF_INET,
+ };
+ int err, port;
+
+ /* Were we already bound to a given port? Try to reuse it */
+ port = xprt->port;
+ do {
+ myaddr.sin_port = htons(port);
+ err = sock->ops->bind(sock, (struct sockaddr *) &myaddr,
+ sizeof(myaddr));
+ if (err == 0) {
+ xprt->port = port;
+ return 0;
+ }
+ if (--port == 0)
+ port = XPRT_MAX_RESVPORT;
+ } while (err == -EADDRINUSE && port != xprt->port);
+
+ printk("RPC: Can't bind to reserved port (%d).\n", -err);
+ return err;
+}
+
+static void
+xprt_bind_socket(struct rpc_xprt *xprt, struct socket *sock)
+{
+ struct sock *sk = sock->sk;
+
+ if (xprt->inet)
+ return;
+
+ write_lock_bh(&sk->sk_callback_lock);
+ sk->sk_user_data = xprt;
+ xprt->old_data_ready = sk->sk_data_ready;
+ xprt->old_state_change = sk->sk_state_change;
+ xprt->old_write_space = sk->sk_write_space;
+ if (xprt->prot == IPPROTO_UDP) {
+ sk->sk_data_ready = udp_data_ready;
+ sk->sk_no_check = UDP_CSUM_NORCV;
+ xprt_set_connected(xprt);
+ } else {
+ tcp_sk(sk)->nonagle = 1; /* disable Nagle's algorithm */
+ sk->sk_data_ready = tcp_data_ready;
+ sk->sk_state_change = tcp_state_change;
+ xprt_clear_connected(xprt);
+ }
+ sk->sk_write_space = xprt_write_space;
+
+ /* Reset to new socket */
+ xprt->sock = sock;
+ xprt->inet = sk;
+ write_unlock_bh(&sk->sk_callback_lock);
+
+ return;
+}
+
+/*
+ * Set socket buffer length
+ */
+void
+xprt_sock_setbufsize(struct rpc_xprt *xprt)
+{
+ struct sock *sk = xprt->inet;
+
+ if (xprt->stream)
+ return;
+ if (xprt->rcvsize) {
+ sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
+ sk->sk_rcvbuf = xprt->rcvsize * xprt->max_reqs * 2;
+ }
+ if (xprt->sndsize) {
+ sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
+ sk->sk_sndbuf = xprt->sndsize * xprt->max_reqs * 2;
+ sk->sk_write_space(sk);
+ }
+}
+
+/*
+ * Datastream sockets are created here, but xprt_connect will create
+ * and connect stream sockets.
+ */
+static struct socket * xprt_create_socket(struct rpc_xprt *xprt, int proto, int resvport)
+{
+ struct socket *sock;
+ int type, err;
+
+ dprintk("RPC: xprt_create_socket(%s %d)\n",
+ (proto == IPPROTO_UDP)? "udp" : "tcp", proto);
+
+ type = (proto == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;
+
+ if ((err = sock_create_kern(PF_INET, type, proto, &sock)) < 0) {
+ printk("RPC: can't create socket (%d).\n", -err);
+ return NULL;
+ }
+
+ /* If the caller has the capability, bind to a reserved port */
+ if (resvport && xprt_bindresvport(xprt, sock) < 0) {
+ printk("RPC: can't bind to reserved port.\n");
+ goto failed;
+ }
+
+ return sock;
+
+failed:
+ sock_release(sock);
+ return NULL;
+}
+
+/*
+ * Create an RPC client transport given the protocol and peer address.
+ */
+struct rpc_xprt *
+xprt_create_proto(int proto, struct sockaddr_in *sap, struct rpc_timeout *to)
+{
+ struct rpc_xprt *xprt;
+
+ xprt = xprt_setup(proto, sap, to);
+ if (IS_ERR(xprt))
+ dprintk("RPC: xprt_create_proto failed\n");
+ else
+ dprintk("RPC: xprt_create_proto created xprt %p\n", xprt);
+ return xprt;
+}
+
+/*
+ * Prepare for transport shutdown.
+ */
+static void
+xprt_shutdown(struct rpc_xprt *xprt)
+{
+ xprt->shutdown = 1;
+ rpc_wake_up(&xprt->sending);
+ rpc_wake_up(&xprt->resend);
+ rpc_wake_up(&xprt->pending);
+ rpc_wake_up(&xprt->backlog);
+ wake_up(&xprt->cong_wait);
+ del_timer_sync(&xprt->timer);
+}
+
+/*
+ * Clear the xprt backlog queue
+ */
+static int
+xprt_clear_backlog(struct rpc_xprt *xprt) {
+ rpc_wake_up_next(&xprt->backlog);
+ wake_up(&xprt->cong_wait);
+ return 1;
+}
+
+/*
+ * Destroy an RPC transport, killing off all requests.
+ */
+int
+xprt_destroy(struct rpc_xprt *xprt)
+{
+ dprintk("RPC: destroying transport %p\n", xprt);
+ xprt_shutdown(xprt);
+ xprt_disconnect(xprt);
+ xprt_close(xprt);
+ kfree(xprt->slot);
+ kfree(xprt);
+
+ return 0;
+}