File: [Development] / linux-2.4-xfs / net / sunrpc / xprt.c (download)
Revision 1.2, Mon Nov 22 13:43:01 2004 UTC (12 years, 11 months ago) by nathans.longdrop.melbourne.sgi.com
Branch: MAIN
CVS Tags: HEAD
Changes since 1.1: +13 -13
lines
Merge up to 2.4.28.
Merge of 2.4.x-xfs-melb:linux:20239a by kenmcd.
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/*
* 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>
*/
#define __KERNEL_SYSCALLS__
#include <linux/version.h>
#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/unistd.h>
#include <linux/sunrpc/clnt.h>
#include <linux/file.h>
#include <net/sock.h>
#include <net/checksum.h>
#include <net/udp.h>
#include <net/tcp.h>
#include <asm/uaccess.h>
/*
* Local variables
*/
#ifdef RPC_DEBUG
# undef RPC_DEBUG_DATA
# define RPCDBG_FACILITY RPCDBG_XPRT
#endif
#define XPRT_MAX_BACKOFF (8)
/*
* Local functions
*/
static void xprt_request_init(struct rpc_task *, struct rpc_xprt *);
static void do_xprt_transmit(struct rpc_task *);
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 socket *xprt_create_socket(int, struct rpc_timeout *, int);
static int xprt_bind_socket(struct rpc_xprt *, struct socket *);
static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
#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->user_data;
}
/*
* Serialize write access to sockets, in order to prevent different
* requests from interfering with each other.
* Also prevents TCP socket connections 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 (!xprt->snd_task) {
if (xprt->nocong || __xprt_get_cong(xprt, task)) {
xprt->snd_task = task;
if (req) {
req->rq_bytes_sent = 0;
req->rq_ntrans++;
}
}
}
if (xprt->snd_task != task) {
dprintk("RPC: %4d TCP write queue full\n", task->tk_pid);
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 xprt->snd_task == task;
}
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 (xprt->snd_task)
return;
task = rpc_wake_up_next(&xprt->resend);
if (!task) {
if (!xprt->nocong && RPCXPRT_CONGESTED(xprt))
return;
task = rpc_wake_up_next(&xprt->sending);
if (!task)
return;
}
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++;
}
}
}
/*
* 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;
__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 msghdr msg;
struct xdr_buf *xdr = &req->rq_snd_buf;
struct iovec niv[MAX_IOVEC];
unsigned int niov, slen, skip;
mm_segment_t oldfs;
int result;
if (!sock)
return -ENOTCONN;
xprt_pktdump("packet data:",
req->rq_svec->iov_base,
req->rq_svec->iov_len);
/* Dont repeat bytes */
skip = req->rq_bytes_sent;
slen = xdr->len - skip;
oldfs = get_fs(); set_fs(get_ds());
do {
unsigned int slen_part, n;
niov = xdr_kmap(niv, xdr, skip);
if (!niov) {
result = -EAGAIN;
break;
}
msg.msg_flags = MSG_DONTWAIT|MSG_NOSIGNAL;
msg.msg_iov = niv;
msg.msg_iovlen = niov;
msg.msg_name = (struct sockaddr *) &xprt->addr;
msg.msg_namelen = sizeof(xprt->addr);
msg.msg_control = NULL;
msg.msg_controllen = 0;
slen_part = 0;
for (n = 0; n < niov; n++)
slen_part += niv[n].iov_len;
clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
result = sock_sendmsg(sock, &msg, slen_part);
xdr_kunmap(xdr, skip, niov);
skip += slen_part;
slen -= slen_part;
} while (result >= 0 && slen);
set_fs(oldfs);
dprintk("RPC: xprt_sendmsg(%d) = %d\n", slen, 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)
cwnd = RPC_MAXCWND;
__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;
}
/*
* Adjust timeout values etc for next retransmit
*/
int
xprt_adjust_timeout(struct rpc_timeout *to)
{
if (to->to_retries > 0) {
if (to->to_exponential)
to->to_current <<= 1;
else
to->to_current += to->to_increment;
if (to->to_maxval && to->to_current >= to->to_maxval)
to->to_current = to->to_maxval;
} else {
if (to->to_exponential)
to->to_initval <<= 1;
else
to->to_initval += to->to_increment;
if (to->to_maxval && to->to_initval >= to->to_maxval)
to->to_initval = to->to_maxval;
to->to_current = to->to_initval;
}
if (!to->to_current) {
printk(KERN_WARNING "xprt_adjust_timeout: to_current = 0!\n");
to->to_current = 5 * HZ;
}
pprintk("RPC: %lu %s\n", jiffies,
to->to_retries? "retrans" : "timeout");
return to->to_retries-- > 0;
}
/*
* 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->callback_lock);
xprt->inet = NULL;
xprt->sock = NULL;
sk->user_data = NULL;
sk->data_ready = xprt->old_data_ready;
sk->state_change = xprt->old_state_change;
sk->write_space = xprt->old_write_space;
write_unlock_bh(&sk->callback_lock);
xprt_disconnect(xprt);
sk->no_check = 0;
sock_release(sock);
}
/*
* 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);
}
/*
* Reconnect a broken TCP connection.
*
*/
void
xprt_connect(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
struct socket *sock = xprt->sock;
struct sock *inet;
int status;
dprintk("RPC: %4d xprt_connect %p connected %d\n",
task->tk_pid, xprt, xprt_connected(xprt));
if (xprt->shutdown)
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;
xprt_close(xprt);
/* Create an unconnected socket */
sock = xprt_create_socket(xprt->prot, &xprt->timeout, xprt->resvport);
if (!sock) {
/* couldn't create socket or bind to reserved port;
* this is likely a permanent error, so cause an abort */
task->tk_status = -EIO;
goto out_write;
}
xprt_bind_socket(xprt, sock);
if (!xprt->stream)
goto out_write;
inet = sock->sk;
/* Now connect it asynchronously. */
dprintk("RPC: %4d connecting new socket\n", task->tk_pid);
status = sock->ops->connect(sock, (struct sockaddr *) &xprt->addr,
sizeof(xprt->addr), O_NONBLOCK);
dprintk("RPC: %4d connect status %d connected %d\n",
task->tk_pid, status, xprt_connected(xprt));
if (status >= 0)
return;
switch (status) {
case -EALREADY:
case -EINPROGRESS:
/* Protect against TCP socket state changes */
lock_sock(inet);
if (inet->state != TCP_ESTABLISHED) {
dprintk("RPC: %4d waiting for connection\n",
task->tk_pid);
task->tk_timeout = RPC_CONNECT_TIMEOUT;
/* if the socket is already closing, delay briefly */
if ((1<<inet->state) & ~(TCPF_SYN_SENT|TCPF_SYN_RECV))
task->tk_timeout = RPC_REESTABLISH_TIMEOUT;
rpc_sleep_on(&xprt->pending, task, xprt_connect_status,
NULL);
}
release_sock(inet);
break;
case -ECONNREFUSED:
case -ECONNRESET:
case -ENOTCONN:
if (!task->tk_client->cl_softrtry) {
rpc_delay(task, RPC_REESTABLISH_TIMEOUT);
task->tk_status = -ENOTCONN;
break;
}
default:
/* Report myriad other possible returns. If this file
* system is soft mounted, just error out, like Solaris. */
if (task->tk_client->cl_softrtry) {
printk(KERN_WARNING
"RPC: error %d connecting to server %s, exiting\n",
-status, task->tk_client->cl_server);
task->tk_status = -EIO;
goto out_write;
}
printk(KERN_WARNING "RPC: error %d connecting to server %s\n",
-status, task->tk_client->cl_server);
/* This will prevent anybody else from connecting */
rpc_delay(task, RPC_REESTABLISH_TIMEOUT);
task->tk_status = status;
break;
}
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, cause this RPC to fail */
if (task->tk_client->cl_softrtry)
task->tk_status = -EIO;
switch (task->tk_status) {
case -ENOTCONN:
rpc_delay(task, RPC_REESTABLISH_TIMEOUT);
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) {
int timer = rpcproc_timer(clnt, task->tk_msg.rpc_proc);
xprt_adjust_cwnd(xprt, copied);
__xprt_put_cong(xprt, req);
if (req->rq_ntrans == 1) {
if (timer)
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 = 0;
static unsigned long pkt_rtt = 0, pkt_len = 0, pkt_cnt = 0;
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);
req->rq_received = copied;
list_del_init(&req->rq_list);
/* ... 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;
skb_copy_bits(desc->skb, desc->offset, to, len);
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
*/
static 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 ((unsigned short)csum_fold(desc.csum))
return -1;
return 0;
no_checksum:
xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_bits);
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;
read_lock(&sk->callback_lock);
dprintk("RPC: udp_data_ready...\n");
if (sk->dead || !(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;
}
/* Look up and lock the request corresponding to the given XID */
spin_lock(&xprt->sock_lock);
rovr = xprt_lookup_rqst(xprt, *(u32 *) (skb->h.raw + sizeof(struct udphdr)));
if (!rovr)
goto out_unlock;
task = rovr->rq_task;
dprintk("RPC: %4d received reply\n", task->tk_pid);
xprt_pktdump("packet data:",
(u32 *) (skb->h.raw+sizeof(struct udphdr)), repsize);
if ((copied = rovr->rq_private_buf.len) > 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:
if (sk->sleep && waitqueue_active(sk->sleep))
wake_up_interruptible(sk->sleep);
read_unlock(&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;
skb_copy_bits(desc->skb, desc->offset, p, len);
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", 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",
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.len)
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 = (struct rpc_xprt *)rd_desc->buf;
skb_reader_t desc = { skb, offset, len };
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->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.buf = (char *)xprt;
rd_desc.count = 65536;
tcp_read_sock(sk, &rd_desc, tcp_data_recv);
out:
read_unlock(&sk->callback_lock);
}
static void
tcp_state_change(struct sock *sk)
{
struct rpc_xprt *xprt;
read_lock(&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->state, xprt_connected(xprt),
sk->dead, sk->zapped);
switch (sk->state) {
case TCP_ESTABLISHED:
if (xprt_test_and_set_connected(xprt))
break;
/* 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;
spin_lock_bh(&xprt->sock_lock);
if (xprt->snd_task && xprt->snd_task->tk_rpcwait == &xprt->pending)
rpc_wake_up_task(xprt->snd_task);
spin_unlock_bh(&xprt->sock_lock);
break;
case TCP_SYN_SENT:
case TCP_SYN_RECV:
break;
default:
xprt_disconnect(xprt);
break;
}
out:
if (sk->sleep && waitqueue_active(sk->sleep))
wake_up_interruptible_all(sk->sleep);
read_unlock(&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->callback_lock);
if (!(xprt = xprt_from_sock(sk)) || !(sock = sk->socket))
goto out;
if (xprt->shutdown)
goto out;
/* Wait until we have enough socket memory */
if (xprt->stream) {
/* from net/ipv4/tcp.c:tcp_write_space */
if (tcp_wspace(sk) < tcp_min_write_space(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 && xprt->snd_task->tk_rpcwait == &xprt->pending)
rpc_wake_up_task(xprt->snd_task);
spin_unlock_bh(&xprt->sock_lock);
if (sk->sleep && waitqueue_active(sk->sleep))
wake_up_interruptible(sk->sleep);
out:
read_unlock(&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.
*/
void
xprt_transmit(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
dprintk("RPC: %4d xprt_transmit(%x)\n", task->tk_pid,
*(u32 *)(req->rq_svec[0].iov_base));
if (xprt->shutdown)
task->tk_status = -EIO;
if (task->tk_status < 0)
return;
if (task->tk_rpcwait)
rpc_remove_wait_queue(task);
/* 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)));
}
spin_lock_bh(&xprt->sock_lock);
if (req->rq_received != 0 && !req->rq_bytes_sent)
goto out_notrans;
if (!__xprt_lock_write(xprt, task))
goto out_notrans;
if (!xprt_connected(xprt)) {
task->tk_status = -ENOTCONN;
goto out_notrans;
}
if (list_empty(&req->rq_list)) {
/* Update the softirq receive buffer */
memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
sizeof(req->rq_private_buf));
list_add_tail(&req->rq_list, &xprt->recv);
}
spin_unlock_bh(&xprt->sock_lock);
do_xprt_transmit(task);
return;
out_notrans:
spin_unlock_bh(&xprt->sock_lock);
}
static void
do_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;
/* 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;
}
/* If we're doing a resend and have received a reply already,
* then exit early.
* Note, though, that we can't do this if we've already started
* resending down a TCP stream.
*/
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.to_current;
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);
spin_lock_bh(&xprt->sock_lock);
/* Set the task's receive timeout value */
if (!xprt->nocong) {
int timer = rpcproc_timer(clnt, task->tk_msg.rpc_proc);
task->tk_timeout = rpc_calc_rto(&clnt->cl_rtt, timer);
task->tk_timeout <<= rpc_ntimeo(&clnt->cl_rtt, timer);
task->tk_timeout <<= clnt->cl_timeout.to_retries
- req->rq_timeout.to_retries;
if (task->tk_timeout > req->rq_timeout.to_maxval)
task->tk_timeout = req->rq_timeout.to_maxval;
} else
task->tk_timeout = req->rq_timeout.to_current;
/* 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 (xprt->free) {
struct rpc_rqst *req = xprt->free;
xprt->free = req->rq_next;
req->rq_next = NULL;
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);
}
}
/*
* Allocate a 'unique' XID
*/
static u32
xprt_alloc_xid(void)
{
static spinlock_t xid_lock = SPIN_LOCK_UNLOCKED;
static int need_init = 1;
static u32 xid;
u32 ret;
spin_lock(&xid_lock);
if (unlikely(need_init)) {
xid = CURRENT_TIME << 12;
need_init = 0;
}
ret = xid++;
spin_unlock(&xid_lock);
return ret;
}
/*
* 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;
req->rq_task = task;
req->rq_xprt = xprt;
req->rq_xid = xprt_alloc_xid();
INIT_LIST_HEAD(&req->rq_list);
dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
req, 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);
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);
req->rq_next = xprt->free;
xprt->free = req;
xprt_clear_backlog(xprt);
spin_unlock(&xprt->xprt_lock);
}
/*
* Set default timeout parameters
*/
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_current =
to->to_initval =
to->to_increment = incr;
to->to_maxval = incr * retr;
to->to_retries = retr;
to->to_exponential = 0;
}
/*
* Initialize an RPC client
*/
static struct rpc_xprt *
xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to)
{
struct rpc_xprt *xprt;
struct rpc_rqst *req;
int i;
dprintk("RPC: setting up %s transport...\n",
proto == IPPROTO_UDP? "UDP" : "TCP");
if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL)
return NULL;
memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */
xprt->addr = *ap;
xprt->prot = proto;
xprt->stream = (proto == IPPROTO_TCP)? 1 : 0;
if (xprt->stream) {
xprt->cwnd = RPC_MAXCWND;
xprt->nocong = 1;
} else
xprt->cwnd = RPC_INITCWND;
spin_lock_init(&xprt->sock_lock);
spin_lock_init(&xprt->xprt_lock);
init_waitqueue_head(&xprt->cong_wait);
INIT_LIST_HEAD(&xprt->recv);
/* Set timeout parameters */
if (to) {
xprt->timeout = *to;
xprt->timeout.to_current = to->to_initval;
} else
xprt_default_timeout(&xprt->timeout, xprt->prot);
INIT_RPC_WAITQ(&xprt->pending, "xprt_pending");
INIT_RPC_WAITQ(&xprt->sending, "xprt_sending");
INIT_RPC_WAITQ(&xprt->resend, "xprt_resend");
INIT_RPC_WAITQ(&xprt->backlog, "xprt_backlog");
/* initialize free list */
for (i = 0, req = xprt->slot; i < RPC_MAXREQS-1; i++, req++)
req->rq_next = req + 1;
req->rq_next = NULL;
xprt->free = xprt->slot;
/* Check whether we want to use a reserved port */
xprt->resvport = capable(CAP_NET_BIND_SERVICE) ? 1 : 0;
dprintk("RPC: created transport %p\n", xprt);
return xprt;
}
/*
* Bind to a reserved port
*/
static inline int
xprt_bindresvport(struct socket *sock)
{
struct sockaddr_in myaddr;
int err, port;
kernel_cap_t saved_cap = current->cap_effective;
/* Override capabilities.
* They were checked in xprt_create_proto i.e. at mount time
*/
cap_raise (current->cap_effective, CAP_NET_BIND_SERVICE);
memset(&myaddr, 0, sizeof(myaddr));
myaddr.sin_family = AF_INET;
port = 800;
do {
myaddr.sin_port = htons(port);
err = sock->ops->bind(sock, (struct sockaddr *) &myaddr,
sizeof(myaddr));
} while (err == -EADDRINUSE && --port > 0);
current->cap_effective = saved_cap;
if (err < 0)
printk("RPC: Can't bind to reserved port (%d).\n", -err);
return err;
}
static int
xprt_bind_socket(struct rpc_xprt *xprt, struct socket *sock)
{
struct sock *sk = sock->sk;
if (xprt->inet)
return -EBUSY;
write_lock_bh(&sk->callback_lock);
sk->user_data = xprt;
xprt->old_data_ready = sk->data_ready;
xprt->old_state_change = sk->state_change;
xprt->old_write_space = sk->write_space;
if (xprt->prot == IPPROTO_UDP) {
sk->data_ready = udp_data_ready;
sk->no_check = UDP_CSUM_NORCV;
xprt_set_connected(xprt);
} else {
struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp);
tp->nonagle = 1; /* disable Nagle's algorithm */
sk->data_ready = tcp_data_ready;
sk->state_change = tcp_state_change;
xprt_clear_connected(xprt);
}
sk->write_space = xprt_write_space;
/* Reset to new socket */
xprt->sock = sock;
xprt->inet = sk;
write_unlock_bh(&sk->callback_lock);
return 0;
}
/*
* 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->userlocks |= SOCK_RCVBUF_LOCK;
sk->rcvbuf = xprt->rcvsize * RPC_MAXCONG * 2;
}
if (xprt->sndsize) {
sk->userlocks |= SOCK_SNDBUF_LOCK;
sk->sndbuf = xprt->sndsize * RPC_MAXCONG * 2;
sk->write_space(sk);
}
}
/*
* Create a client socket given the protocol and peer address.
*/
static struct socket *
xprt_create_socket(int proto, struct rpc_timeout *to, 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(PF_INET, type, proto, &sock)) < 0) {
printk("RPC: can't create socket (%d).\n", -err);
goto failed;
}
/* bind to a reserved port */
if (resvport && xprt_bindresvport(sock) < 0)
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 (!xprt)
goto out_bad;
dprintk("RPC: xprt_create_proto created xprt %p\n", xprt);
return xprt;
out_bad:
dprintk("RPC: xprt_create_proto failed\n");
if (xprt)
kfree(xprt);
return NULL;
}
/*
* Prepare for transport shutdown.
*/
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);
if (waitqueue_active(&xprt->cong_wait))
wake_up(&xprt->cong_wait);
}
/*
* Clear the xprt backlog queue
*/
int
xprt_clear_backlog(struct rpc_xprt *xprt) {
rpc_wake_up_next(&xprt->backlog);
if (waitqueue_active(&xprt->cong_wait))
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_close(xprt);
kfree(xprt);
return 0;
}
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