Viewing file:  xprt.c (37.65 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* 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 <asm/uaccess.h>
/* Following value should be > 32k + RPC overhead */
#define XPRT_MIN_WRITE_SPACE (35000 + SOCK_MIN_WRITE_SPACE)
extern spinlock_t rpc_queue_lock;
/*
* Local variables
*/
#ifdef RPC_DEBUG
# undef RPC_DEBUG_DATA
# define RPCDBG_FACILITY RPCDBG_XPRT
#endif
/*
* Local functions
*/
static void xprt_request_init(struct rpc_task *, struct rpc_xprt *);
static void do_xprt_transmit(struct rpc_task *);
static void xprt_reserve_status(struct rpc_task *task);
static void xprt_disconnect(struct rpc_xprt *);
static void xprt_reconn_status(struct rpc_task *task);
static struct socket *xprt_create_socket(int, struct rpc_timeout *);
static int xprt_bind_socket(struct rpc_xprt *, struct socket *);
static void xprt_remove_pending(struct rpc_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->user_data;
}
/*
* Adjust the iovec to move on 'n' bytes
*/
extern inline void
xprt_move_iov(struct msghdr *msg, struct iovec *niv, unsigned amount)
{
struct iovec *iv=msg->msg_iov;
int i;
/*
* Eat any sent iovecs
*/
while (iv->iov_len <= amount) {
amount -= iv->iov_len;
iv++;
msg->msg_iovlen--;
}
/*
* And chew down the partial one
*/
niv[0].iov_len = iv->iov_len-amount;
niv[0].iov_base =((unsigned char *)iv->iov_base)+amount;
iv++;
/*
* And copy any others
*/
for(i = 1; i < msg->msg_iovlen; i++)
niv[i]=*iv++;
msg->msg_iov=niv;
}
/*
* Serialize write access to sockets, in order to prevent different
* requests from interfering with each other.
* Also prevents TCP socket reconnections from colliding with writes.
*/
static int
xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
{
int retval;
spin_lock_bh(&xprt->sock_lock);
if (!xprt->snd_task)
xprt->snd_task = task;
else if (xprt->snd_task != task) {
dprintk("RPC: %4d TCP write queue full (task %d)\n",
task->tk_pid, xprt->snd_task->tk_pid);
task->tk_timeout = 0;
task->tk_status = -EAGAIN;
rpc_sleep_on(&xprt->sending, task, NULL, NULL);
}
retval = xprt->snd_task == task;
spin_unlock_bh(&xprt->sock_lock);
return retval;
}
/*
* Releases the socket for use by other requests.
*/
static void
xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
{
spin_lock_bh(&xprt->sock_lock);
if (xprt->snd_task == task) {
xprt->snd_task = NULL;
rpc_wake_up_next(&xprt->sending);
}
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;
mm_segment_t oldfs;
int result;
int slen = req->rq_slen - req->rq_bytes_sent;
struct iovec niv[MAX_IOVEC];
if (slen <= 0)
return 0;
if (!sock)
return -ENOTCONN;
xprt_pktdump("packet data:",
req->rq_svec->iov_base,
req->rq_svec->iov_len);
msg.msg_flags = MSG_DONTWAIT|MSG_NOSIGNAL;
msg.msg_iov = req->rq_svec;
msg.msg_iovlen = req->rq_snr;
msg.msg_name = (struct sockaddr *) &xprt->addr;
msg.msg_namelen = sizeof(xprt->addr);
msg.msg_control = NULL;
msg.msg_controllen = 0;
/* Dont repeat bytes */
if (req->rq_bytes_sent)
xprt_move_iov(&msg, niv, req->rq_bytes_sent);
oldfs = get_fs(); set_fs(get_ds());
result = sock_sendmsg(sock, &msg, 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.
*/
break;
case -EAGAIN:
if (test_bit(SOCK_NOSPACE, &sock->flags))
result = -ENOMEM;
break;
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;
}
/*
* Read data from socket
*/
static int
xprt_recvmsg(struct rpc_xprt *xprt, struct iovec *iov, int nr, unsigned len, unsigned shift)
{
struct socket *sock = xprt->sock;
struct msghdr msg;
mm_segment_t oldfs;
struct iovec niv[MAX_IOVEC];
int result;
if (!sock)
return -ENOTCONN;
msg.msg_flags = MSG_DONTWAIT|MSG_NOSIGNAL;
msg.msg_iov = iov;
msg.msg_iovlen = nr;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_control = NULL;
msg.msg_controllen = 0;
/* Adjust the iovec if we've already filled it */
if (shift)
xprt_move_iov(&msg, niv, shift);
oldfs = get_fs(); set_fs(get_ds());
result = sock_recvmsg(sock, &msg, len, MSG_DONTWAIT);
set_fs(oldfs);
dprintk("RPC: xprt_recvmsg(iov %p, len %d) = %d\n",
iov, len, result);
return result;
}
/*
* 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;
if (xprt->nocong)
return;
/*
* Note: we're in a BH context
*/
spin_lock(&xprt->xprt_lock);
cwnd = xprt->cwnd;
if (result >= 0) {
if (xprt->cong < cwnd || time_before(jiffies, xprt->congtime))
goto out;
/* 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;
else
pprintk("RPC: %lu %ld cwnd\n", jiffies, cwnd);
xprt->congtime = jiffies + ((cwnd * HZ) << 2) / RPC_CWNDSCALE;
dprintk("RPC: cong %08lx, cwnd was %08lx, now %08lx, "
"time %ld ms\n", xprt->cong, xprt->cwnd, cwnd,
(xprt->congtime-jiffies)*1000/HZ);
} else if (result == -ETIMEDOUT) {
if ((cwnd >>= 1) < RPC_CWNDSCALE)
cwnd = RPC_CWNDSCALE;
xprt->congtime = jiffies + ((cwnd * HZ) << 3) / RPC_CWNDSCALE;
dprintk("RPC: cong %ld, cwnd was %ld, now %ld, "
"time %ld ms\n", xprt->cong, xprt->cwnd, cwnd,
(xprt->congtime-jiffies)*1000/HZ);
pprintk("RPC: %lu %ld cwnd\n", jiffies, cwnd);
}
xprt->cwnd = cwnd;
out:
spin_unlock(&xprt->xprt_lock);
}
/*
* 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;
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;
xprt_disconnect(xprt);
sk->no_check = 0;
sock_release(sock);
/*
* TCP doesnt require the rpciod now - other things may
* but rpciod handles that not us.
*/
if(xprt->stream)
rpciod_down();
}
/*
* Mark a transport as disconnected
*/
static void
xprt_disconnect(struct rpc_xprt *xprt)
{
dprintk("RPC: disconnected transport %p\n", xprt);
xprt_clear_connected(xprt);
xprt_remove_pending(xprt);
rpc_wake_up_status(&xprt->pending, -ENOTCONN);
}
/*
* Reconnect a broken TCP connection.
*
* Note: This cannot collide with the TCP reads, as both run from rpciod
*/
void
xprt_reconnect(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
struct socket *sock = xprt->sock;
struct sock *inet = xprt->inet;
int status;
dprintk("RPC: %4d xprt_reconnect %p connected %d\n",
task->tk_pid, xprt, xprt_connected(xprt));
if (xprt->shutdown)
return;
if (!xprt->stream)
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;
status = -ENOTCONN;
if (!inet) {
/* Create an unconnected socket */
if (!(sock = xprt_create_socket(xprt->prot, &xprt->timeout)))
goto defer;
xprt_bind_socket(xprt, sock);
inet = sock->sk;
}
xprt_disconnect(xprt);
/* Reset TCP record info */
xprt->tcp_offset = 0;
xprt->tcp_reclen = 0;
xprt->tcp_copied = 0;
xprt->tcp_more = 0;
/* 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);
if (status < 0) {
switch (status) {
case -EALREADY:
case -EINPROGRESS:
status = 0;
break;
case -EISCONN:
case -EPIPE:
status = 0;
xprt_close(xprt);
goto defer;
default:
printk("RPC: TCP connect error %d!\n", -status);
xprt_close(xprt);
goto defer;
}
dprintk("RPC: %4d connect status %d connected %d\n",
task->tk_pid, status, xprt_connected(xprt));
spin_lock_bh(&xprt->sock_lock);
if (!xprt_connected(xprt)) {
task->tk_timeout = xprt->timeout.to_maxval;
rpc_sleep_on(&xprt->sending, task, xprt_reconn_status, NULL);
spin_unlock_bh(&xprt->sock_lock);
return;
}
spin_unlock_bh(&xprt->sock_lock);
}
defer:
if (status < 0) {
rpc_delay(task, 5*HZ);
task->tk_status = -ENOTCONN;
}
out_write:
xprt_release_write(xprt, task);
}
/*
* Reconnect timeout. We just mark the transport as not being in the
* process of reconnecting, and leave the rest to the upper layers.
*/
static void
xprt_reconn_status(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
dprintk("RPC: %4d xprt_reconn_timeout %d\n",
task->tk_pid, task->tk_status);
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 rpc_task *head, *task;
struct rpc_rqst *req;
int safe = 0;
spin_lock_bh(&rpc_queue_lock);
if ((head = xprt->pending.task) != NULL) {
task = head;
do {
if ((req = task->tk_rqstp) && req->rq_xid == xid)
goto out;
task = task->tk_next;
if (++safe > 100) {
printk("xprt_lookup_rqst: loop in Q!\n");
goto out_bad;
}
} while (task != head);
}
dprintk("RPC: unknown XID %08x in reply.\n", xid);
out_bad:
req = NULL;
out:
if (req && !__rpc_lock_task(req->rq_task))
req = NULL;
spin_unlock_bh(&rpc_queue_lock);
return req;
}
/*
* Complete reply received.
* The TCP code relies on us to remove the request from xprt->pending.
*/
static inline void
xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
{
struct rpc_task *task = req->rq_task;
/* Adjust congestion window */
xprt_adjust_cwnd(xprt, copied);
#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);
task->tk_status = copied;
req->rq_received = 1;
/* ... and wake up the process. */
rpc_wake_up_task(task);
return;
}
/*
* 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_page_cache(struct iovec *iov,
struct sk_buff *skb,
int copied)
{
int offset = sizeof(struct udphdr);
__u8 *cur_ptr = iov->iov_base;
__kernel_size_t cur_len = iov->iov_len;
unsigned int csum = skb->csum;
int need_csum = (skb->ip_summed != CHECKSUM_UNNECESSARY);
int slack = skb->len - copied - sizeof(struct udphdr);
if (need_csum)
csum = csum_partial(skb->data, sizeof(struct udphdr), csum);
while (copied > 0) {
if (cur_len) {
int to_move = cur_len;
if (to_move > copied)
to_move = copied;
if (need_csum) {
unsigned int csum2;
csum2 = skb_copy_and_csum_bits(skb, offset,
cur_ptr,
to_move, 0);
csum = csum_block_add(csum, csum2, offset);
} else
skb_copy_bits(skb, offset, cur_ptr, to_move);
offset += to_move;
copied -= to_move;
cur_ptr += to_move;
cur_len -= to_move;
}
if (cur_len <= 0) {
iov++;
cur_len = iov->iov_len;
cur_ptr = iov->iov_base;
}
}
if (need_csum) {
if (slack > 0) {
unsigned int csum2;
csum2 = skb_checksum(skb, offset, slack, 0);
csum = csum_block_add(csum, csum2, offset);
}
if ((unsigned short)csum_fold(csum))
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;
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;
}
/* Look up and lock the request corresponding to the given XID */
rovr = xprt_lookup_rqst(xprt, *(u32 *) (skb->h.raw + sizeof(struct udphdr)));
if (!rovr)
goto dropit;
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_rlen) > repsize)
copied = repsize;
/* Suck it into the iovec, verify checksum if not done by hw. */
if (csum_partial_copy_to_page_cache(rovr->rq_rvec, skb, copied))
goto out_unlock;
/* Something worked... */
dst_confirm(skb->dst);
xprt_complete_rqst(xprt, rovr, copied);
out_unlock:
rpc_unlock_task(task);
dropit:
skb_free_datagram(sk, skb);
out:
if (sk->sleep && waitqueue_active(sk->sleep))
wake_up_interruptible(sk->sleep);
}
/*
* TCP read fragment marker
*/
static inline int
tcp_read_fraghdr(struct rpc_xprt *xprt)
{
struct iovec riov;
int want, result;
if (xprt->tcp_offset >= sizeof(xprt->tcp_recm))
goto done;
want = sizeof(xprt->tcp_recm) - xprt->tcp_offset;
dprintk("RPC: reading header (%d bytes)\n", want);
do {
riov.iov_base = ((u8*) &xprt->tcp_recm) + xprt->tcp_offset;
riov.iov_len = want;
result = xprt_recvmsg(xprt, &riov, 1, want, 0);
if (result < 0)
return result;
xprt->tcp_offset += result;
want -= result;
} while (want);
/* Get the record length and mask out the last fragment bit */
xprt->tcp_reclen = ntohl(xprt->tcp_recm);
xprt->tcp_more = (xprt->tcp_reclen & 0x80000000) ? 0 : 1;
xprt->tcp_reclen &= 0x7fffffff;
dprintk("RPC: New record reclen %d morefrags %d\n",
xprt->tcp_reclen, xprt->tcp_more);
done:
return xprt->tcp_reclen + sizeof(xprt->tcp_recm) - xprt->tcp_offset;
}
/*
* TCP read xid
*/
static inline int
tcp_read_xid(struct rpc_xprt *xprt, int avail)
{
struct iovec riov;
int want, result;
if (xprt->tcp_copied >= sizeof(xprt->tcp_xid) || !avail)
goto done;
want = min_t(unsigned int, sizeof(xprt->tcp_xid) - xprt->tcp_copied, avail);
do {
dprintk("RPC: reading xid (%d bytes)\n", want);
riov.iov_base = ((u8*) &xprt->tcp_xid) + xprt->tcp_copied;
riov.iov_len = want;
result = xprt_recvmsg(xprt, &riov, 1, want, 0);
if (result < 0)
return result;
xprt->tcp_copied += result;
xprt->tcp_offset += result;
want -= result;
avail -= result;
} while (want);
done:
return avail;
}
/*
* TCP read and complete request
*/
static inline int
tcp_read_request(struct rpc_xprt *xprt, struct rpc_rqst *req, int avail)
{
int want, result;
if (req->rq_rlen <= xprt->tcp_copied || !avail)
goto done;
want = min_t(unsigned int, req->rq_rlen - xprt->tcp_copied, avail);
do {
dprintk("RPC: %4d TCP receiving %d bytes\n",
req->rq_task->tk_pid, want);
result = xprt_recvmsg(xprt, req->rq_rvec, req->rq_rnr, want, xprt->tcp_copied);
if (result < 0)
return result;
xprt->tcp_copied += result;
xprt->tcp_offset += result;
avail -= result;
want -= result;
} while (want);
done:
if (req->rq_rlen > xprt->tcp_copied && xprt->tcp_more)
return avail;
dprintk("RPC: %4d received reply complete\n", req->rq_task->tk_pid);
xprt_complete_rqst(xprt, req, xprt->tcp_copied);
return avail;
}
/*
* TCP discard extra bytes from a short read
*/
static inline int
tcp_read_discard(struct rpc_xprt *xprt, int avail)
{
struct iovec riov;
static u8 dummy[64];
int want, result = 0;
while (avail) {
want = min_t(unsigned int, avail, sizeof(dummy));
riov.iov_base = dummy;
riov.iov_len = want;
dprintk("RPC: TCP skipping %d bytes\n", want);
result = xprt_recvmsg(xprt, &riov, 1, want, 0);
if (result < 0)
return result;
xprt->tcp_offset += result;
avail -= result;
}
return avail;
}
/*
* TCP record receive routine
* This is not the most efficient code since we call recvfrom thrice--
* first receiving the record marker, then the XID, then the data.
*
* The optimal solution would be a RPC support in the TCP layer, which
* would gather all data up to the next record marker and then pass us
* the list of all TCP segments ready to be copied.
*/
static int
tcp_input_record(struct rpc_xprt *xprt)
{
struct rpc_rqst *req = NULL;
struct rpc_task *task = NULL;
int avail, result;
dprintk("RPC: tcp_input_record\n");
if (xprt->shutdown)
return -EIO;
if (!xprt_connected(xprt))
return -ENOTCONN;
/* Read in a new fragment marker if necessary */
/* Can we ever really expect to get completely empty fragments? */
if ((result = tcp_read_fraghdr(xprt)) < 0)
return result;
avail = result;
/* Read in the xid if necessary */
if ((result = tcp_read_xid(xprt, avail)) < 0)
return result;
if (!(avail = result))
goto out_ok;
/* Find and lock the request corresponding to this xid */
req = xprt_lookup_rqst(xprt, xprt->tcp_xid);
if (req) {
task = req->rq_task;
/* Read in the request data */
result = tcp_read_request(xprt, req, avail);
rpc_unlock_task(task);
if (result < 0)
return result;
avail = result;
}
/* Skip over any trailing bytes on short reads */
if ((result = tcp_read_discard(xprt, avail)) < 0)
return result;
out_ok:
dprintk("RPC: tcp_input_record done (off %d reclen %d copied %d)\n",
xprt->tcp_offset, xprt->tcp_reclen, xprt->tcp_copied);
result = xprt->tcp_reclen;
xprt->tcp_reclen = 0;
xprt->tcp_offset = 0;
if (!xprt->tcp_more)
xprt->tcp_copied = 0;
return result;
}
/*
* TCP task queue stuff
*/
LIST_HEAD(rpc_xprt_pending); /* List of xprts having pending tcp requests */
static inline
void tcp_rpciod_queue(void)
{
rpciod_wake_up();
}
int xprt_tcp_pending(void)
{
int retval;
spin_lock_bh(&rpc_queue_lock);
retval = !list_empty(&rpc_xprt_pending);
spin_unlock_bh(&rpc_queue_lock);
return retval;
}
static inline
void xprt_append_pending(struct rpc_xprt *xprt)
{
spin_lock_bh(&rpc_queue_lock);
if (list_empty(&xprt->rx_pending)) {
list_add(&xprt->rx_pending, rpc_xprt_pending.prev);
dprintk("RPC: xprt queue %p\n", xprt);
tcp_rpciod_queue();
}
spin_unlock_bh(&rpc_queue_lock);
}
static
void xprt_remove_pending(struct rpc_xprt *xprt)
{
spin_lock_bh(&rpc_queue_lock);
if (!list_empty(&xprt->rx_pending)) {
list_del(&xprt->rx_pending);
INIT_LIST_HEAD(&xprt->rx_pending);
}
spin_unlock_bh(&rpc_queue_lock);
}
static inline
struct rpc_xprt *xprt_remove_pending_next(void)
{
struct rpc_xprt *xprt = NULL;
spin_lock_bh(&rpc_queue_lock);
if (!list_empty(&rpc_xprt_pending)) {
xprt = list_entry(rpc_xprt_pending.next, struct rpc_xprt, rx_pending);
list_del(&xprt->rx_pending);
INIT_LIST_HEAD(&xprt->rx_pending);
}
spin_unlock_bh(&rpc_queue_lock);
return xprt;
}
/*
* This is protected from tcp_data_ready and the stack as its run
* inside of the RPC I/O daemon
*/
void
__rpciod_tcp_dispatcher(void)
{
struct rpc_xprt *xprt;
int safe_retry = 0, result;
dprintk("rpciod_tcp_dispatcher: Queue Running\n");
/*
* Empty each pending socket
*/
while ((xprt = xprt_remove_pending_next()) != NULL) {
dprintk("rpciod_tcp_dispatcher: Processing %p\n", xprt);
do {
result = tcp_input_record(xprt);
} while (result >= 0);
if (safe_retry++ > 200) {
schedule();
safe_retry = 0;
}
}
}
/*
* data_ready callback for TCP. We can't just jump into the
* tcp recvmsg functions inside of the network receive bh or
* bad things occur. We queue it to pick up after networking
* is done.
*/
static void tcp_data_ready(struct sock *sk, int len)
{
struct rpc_xprt *xprt;
dprintk("RPC: tcp_data_ready...\n");
if (!(xprt = xprt_from_sock(sk)))
{
printk("Not a socket with xprt %p\n", sk);
goto out;
}
if (xprt->shutdown)
goto out;
xprt_append_pending(xprt);
dprintk("RPC: tcp_data_ready client %p\n", xprt);
dprintk("RPC: state %x conn %d dead %d zapped %d\n",
sk->state, xprt_connected(xprt),
sk->dead, sk->zapped);
out:
if (sk->sleep && waitqueue_active(sk->sleep))
wake_up_interruptible(sk->sleep);
}
static void
tcp_state_change(struct sock *sk)
{
struct rpc_xprt *xprt;
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;
spin_lock(&xprt->sock_lock);
if (xprt->snd_task && xprt->snd_task->tk_rpcwait == &xprt->sending)
rpc_wake_up_task(xprt->snd_task);
spin_unlock(&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);
}
/*
* The following 2 routines allow a task to sleep while socket memory is
* low.
*/
static void
tcp_write_space(struct sock *sk)
{
struct rpc_xprt *xprt;
struct socket *sock;
if (!(xprt = xprt_from_sock(sk)) || !(sock = sk->socket))
return;
if (xprt->shutdown)
return;
/* Wait until we have enough socket memory */
if (!sock_writeable(sk))
return;
if (!xprt_test_and_set_wspace(xprt)) {
spin_lock(&xprt->sock_lock);
if (xprt->snd_task && xprt->snd_task->tk_rpcwait == &xprt->sending)
rpc_wake_up_task(xprt->snd_task);
spin_unlock(&xprt->sock_lock);
}
if (test_bit(SOCK_NOSPACE, &sock->flags)) {
if (sk->sleep && waitqueue_active(sk->sleep)) {
clear_bit(SOCK_NOSPACE, &sock->flags);
wake_up_interruptible(sk->sleep);
}
}
}
static void
udp_write_space(struct sock *sk)
{
struct rpc_xprt *xprt;
if (!(xprt = xprt_from_sock(sk)))
return;
if (xprt->shutdown)
return;
/* Wait until we have enough socket memory */
if (sock_wspace(sk) < min_t(int, sk->sndbuf,XPRT_MIN_WRITE_SPACE))
return;
if (!xprt_test_and_set_wspace(xprt)) {
spin_lock(&xprt->sock_lock);
if (xprt->snd_task && xprt->snd_task->tk_rpcwait == &xprt->sending)
rpc_wake_up_task(xprt->snd_task);
spin_unlock(&xprt->sock_lock);
}
if (sk->sleep && waitqueue_active(sk->sleep))
wake_up_interruptible(sk->sleep);
}
/*
* RPC receive timeout handler.
*/
static void
xprt_timer(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
if (req)
xprt_adjust_cwnd(task->tk_xprt, -ETIMEDOUT);
dprintk("RPC: %4d xprt_timer (%s request)\n",
task->tk_pid, req ? "pending" : "backlogged");
task->tk_status = -ETIMEDOUT;
task->tk_timeout = 0;
rpc_wake_up_task(task);
}
/*
* 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 (!xprt_connected(xprt))
task->tk_status = -ENOTCONN;
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)));
}
if (!xprt_lock_write(xprt, task))
return;
#ifdef RPC_PROFILE
req->rq_xtime = jiffies;
#endif
do_xprt_transmit(task);
}
static void
do_xprt_transmit(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
int status, retry = 0;
/* For fast networks/servers we have to put the request on
* the pending list now:
* Note that we don't want the task timing out during the
* call to xprt_sendmsg(), so we initially disable the timeout,
* and then reset it later...
*/
xprt_receive(task);
/* Continue transmitting the packet/record. We must be careful
* to cope with writespace callbacks arriving _after_ we have
* called xprt_sendmsg().
*/
while (1) {
xprt_clear_wspace(xprt);
status = xprt_sendmsg(xprt, req);
if (status < 0)
break;
if (xprt->stream) {
req->rq_bytes_sent += status;
if (req->rq_bytes_sent >= req->rq_slen)
goto out_receive;
} else {
if (status >= req->rq_slen)
goto out_receive;
status = -ENOMEM;
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;
}
rpc_unlock_task(task);
/* 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().
*/
rpc_wake_up_task(task);
if (!RPC_IS_RUNNING(task))
goto out_release;
if (req->rq_received)
goto out_release;
task->tk_status = status;
switch (status) {
case -ENOMEM:
/* Protect against (udp|tcp)_write_space */
spin_lock_bh(&xprt->sock_lock);
if (!xprt_wspace(xprt)) {
task->tk_timeout = req->rq_timeout.to_current;
rpc_sleep_on(&xprt->sending, task, NULL, NULL);
}
spin_unlock_bh(&xprt->sock_lock);
return;
case -EAGAIN:
/* Keep holding the socket if it is blocked */
rpc_delay(task, HZ>>4);
return;
case -ECONNREFUSED:
case -ENOTCONN:
if (!xprt->stream)
return;
default:
if (xprt->stream)
xprt_disconnect(xprt);
req->rq_bytes_sent = 0;
goto out_release;
}
out_receive:
dprintk("RPC: %4d xmit complete\n", task->tk_pid);
/* Set the task's receive timeout value */
task->tk_timeout = req->rq_timeout.to_current;
rpc_add_timer(task, xprt_timer);
rpc_unlock_task(task);
out_release:
xprt_release_write(xprt, task);
}
/*
* Queue the task for a reply to our call.
* When the callback is invoked, the congestion window should have
* been updated already.
*/
void
xprt_receive(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
dprintk("RPC: %4d xprt_receive\n", task->tk_pid);
req->rq_received = 0;
task->tk_timeout = 0;
rpc_sleep_locked(&xprt->pending, task, NULL, NULL);
}
/*
* Reserve an RPC call slot.
*/
int
xprt_reserve(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
/* We already have an initialized request. */
if (task->tk_rqstp)
return 0;
dprintk("RPC: %4d xprt_reserve cong = %ld cwnd = %ld\n",
task->tk_pid, xprt->cong, xprt->cwnd);
spin_lock_bh(&xprt->xprt_lock);
xprt_reserve_status(task);
if (task->tk_rqstp) {
task->tk_timeout = 0;
} else if (!task->tk_timeout) {
task->tk_status = -ENOBUFS;
} else {
dprintk("RPC: xprt_reserve waiting on backlog\n");
task->tk_status = -EAGAIN;
rpc_sleep_on(&xprt->backlog, task, NULL, NULL);
}
spin_unlock_bh(&xprt->xprt_lock);
dprintk("RPC: %4d xprt_reserve returns %d\n",
task->tk_pid, task->tk_status);
return task->tk_status;
}
/*
* Reservation callback
*/
static void
xprt_reserve_status(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
struct rpc_rqst *req;
if (xprt->shutdown) {
task->tk_status = -EIO;
} else if (task->tk_status < 0) {
/* NOP */
} else if (task->tk_rqstp) {
/* We've already been given a request slot: NOP */
} else {
if (RPCXPRT_CONGESTED(xprt) || !(req = xprt->free))
goto out_nofree;
/* OK: There's room for us. Grab a free slot and bump
* congestion value */
xprt->free = req->rq_next;
req->rq_next = NULL;
xprt->cong += RPC_CWNDSCALE;
task->tk_rqstp = req;
xprt_request_init(task, xprt);
if (xprt->free)
xprt_clear_backlog(xprt);
}
return;
out_nofree:
task->tk_status = -EAGAIN;
}
/*
* Initialize RPC request
*/
static void
xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
{
struct rpc_rqst *req = task->tk_rqstp;
static u32 xid = 0;
if (!xid)
xid = CURRENT_TIME << 12;
dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid, req, xid);
task->tk_status = 0;
req->rq_timeout = xprt->timeout;
req->rq_task = task;
req->rq_xprt = xprt;
req->rq_xid = xid++;
if (!xid)
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 (xprt->snd_task == task) {
if (xprt->stream)
xprt_disconnect(xprt);
xprt_release_write(xprt, task);
}
if (!(req = task->tk_rqstp))
return;
task->tk_rqstp = NULL;
memset(req, 0, sizeof(*req)); /* mark unused */
dprintk("RPC: %4d release request %p\n", task->tk_pid, req);
spin_lock_bh(&xprt->xprt_lock);
req->rq_next = xprt->free;
xprt->free = req;
/* Decrease congestion value. */
xprt->cong -= RPC_CWNDSCALE;
xprt_clear_backlog(xprt);
spin_unlock_bh(&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_resrvval = incr * retr;
to->to_retries = retr;
to->to_exponential = 0;
}
/*
* Initialize an RPC client
*/
static struct rpc_xprt *
xprt_setup(struct socket *sock, 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;
xprt->congtime = jiffies;
spin_lock_init(&xprt->sock_lock);
spin_lock_init(&xprt->xprt_lock);
init_waitqueue_head(&xprt->cong_wait);
/* Set timeout parameters */
if (to) {
xprt->timeout = *to;
xprt->timeout.to_current = to->to_initval;
xprt->timeout.to_resrvval = to->to_maxval << 1;
} else
xprt_default_timeout(&xprt->timeout, xprt->prot);
xprt->pending = RPC_INIT_WAITQ("xprt_pending");
xprt->sending = RPC_INIT_WAITQ("xprt_sending");
xprt->backlog = RPC_INIT_WAITQ("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;
INIT_LIST_HEAD(&xprt->rx_pending);
dprintk("RPC: created transport %p\n", xprt);
xprt_bind_socket(xprt, sock);
return xprt;
}
/*
* Bind to a reserved port
*/
static inline int
xprt_bindresvport(struct socket *sock)
{
struct sockaddr_in myaddr;
int err, port;
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);
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;
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->write_space = udp_write_space;
sk->no_check = UDP_CSUM_NORCV;
xprt_set_connected(xprt);
} else {
sk->data_ready = tcp_data_ready;
sk->state_change = tcp_state_change;
sk->write_space = tcp_write_space;
xprt_clear_connected(xprt);
}
/* Reset to new socket */
xprt->sock = sock;
xprt->inet = sk;
/*
* TCP requires the rpc I/O daemon is present
*/
if(xprt->stream)
rpciod_up();
return 0;
}
/*
* Create a client socket given the protocol and peer address.
*/
static struct socket *
xprt_create_socket(int proto, struct rpc_timeout *to)
{
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;
}
/* If the caller has the capability, bind to a reserved port */
if (capable(CAP_NET_BIND_SERVICE) && 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 socket *sock;
struct rpc_xprt *xprt;
dprintk("RPC: xprt_create_proto called\n");
if (!(sock = xprt_create_socket(proto, to)))
return NULL;
if (!(xprt = xprt_setup(sock, proto, sap, to)))
sock_release(sock);
return xprt;
}
/*
* Prepare for transport shutdown.
*/
void
xprt_shutdown(struct rpc_xprt *xprt)
{
xprt->shutdown = 1;
rpc_wake_up(&xprt->sending);
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) {
if (RPCXPRT_CONGESTED(xprt))
return 0;
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;
}
|