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OpenCloudOS-Kernel/net/sunrpc/xprt.c

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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_transmit().
* - xprt_transmit sends the message and installs the caller on the
* transport'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 transport. 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>
*
* Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/random.h>
#include <linux/sunrpc/clnt.h>
/*
* 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 inline void do_xprt_reserve(struct rpc_task *);
static void xprt_connect_status(struct rpc_task *task);
static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
/*
* The transport code maintains an estimate on the maximum number of out-
* standing RPC requests, using a smoothed version of the congestion
* avoidance implemented in 44BSD. This is basically the Van Jacobson
* congestion algorithm: If a retransmit occurs, the congestion window is
* halved; otherwise, it is incremented by 1/cwnd when
*
* - a reply is received and
* - a full number of requests are outstanding and
* - the congestion window hasn't been updated recently.
*/
#define RPC_CWNDSHIFT (8U)
#define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT)
#define RPC_INITCWND RPC_CWNDSCALE
#define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT)
#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
/**
* xprt_reserve_xprt - serialize write access to transports
* @task: task that is requesting access to the transport
*
* This prevents mixing the payload of separate requests, and prevents
* transport connects from colliding with writes. No congestion control
* is provided.
*/
int xprt_reserve_xprt(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
struct rpc_rqst *req = task->tk_rqstp;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
if (task == xprt->snd_task)
return 1;
if (task == NULL)
return 0;
goto out_sleep;
}
xprt->snd_task = task;
if (req) {
req->rq_bytes_sent = 0;
req->rq_ntrans++;
}
return 1;
out_sleep:
dprintk("RPC: %4d failed to lock transport %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 void xprt_clear_locked(struct rpc_xprt *xprt)
{
xprt->snd_task = NULL;
if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state) || xprt->shutdown) {
smp_mb__before_clear_bit();
clear_bit(XPRT_LOCKED, &xprt->state);
smp_mb__after_clear_bit();
} else
schedule_work(&xprt->task_cleanup);
}
/*
* xprt_reserve_xprt_cong - serialize write access to transports
* @task: task that is requesting access to the transport
*
* Same as xprt_reserve_xprt, but Van Jacobson congestion control is
* integrated into the decision of whether a request is allowed to be
* woken up and given access to the transport.
*/
int xprt_reserve_xprt_cong(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
struct rpc_rqst *req = task->tk_rqstp;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
if (task == xprt->snd_task)
return 1;
goto out_sleep;
}
if (__xprt_get_cong(xprt, task)) {
xprt->snd_task = task;
if (req) {
req->rq_bytes_sent = 0;
req->rq_ntrans++;
}
return 1;
}
xprt_clear_locked(xprt);
out_sleep:
dprintk("RPC: %4d failed to lock transport %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->transport_lock);
retval = xprt->ops->reserve_xprt(task);
spin_unlock_bh(&xprt->transport_lock);
return retval;
}
static void __xprt_lock_write_next(struct rpc_xprt *xprt)
{
struct rpc_task *task;
struct rpc_rqst *req;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
return;
task = rpc_wake_up_next(&xprt->resend);
if (!task) {
task = rpc_wake_up_next(&xprt->sending);
if (!task)
goto out_unlock;
}
req = task->tk_rqstp;
xprt->snd_task = task;
if (req) {
req->rq_bytes_sent = 0;
req->rq_ntrans++;
}
return;
out_unlock:
xprt_clear_locked(xprt);
}
static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
{
struct rpc_task *task;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
return;
if (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_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:
xprt_clear_locked(xprt);
}
/**
* xprt_release_xprt - allow other requests to use a transport
* @xprt: transport with other tasks potentially waiting
* @task: task that is releasing access to the transport
*
* Note that "task" can be NULL. No congestion control is provided.
*/
void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
{
if (xprt->snd_task == task) {
xprt_clear_locked(xprt);
__xprt_lock_write_next(xprt);
}
}
/**
* xprt_release_xprt_cong - allow other requests to use a transport
* @xprt: transport with other tasks potentially waiting
* @task: task that is releasing access to the transport
*
* Note that "task" can be NULL. Another task is awoken to use the
* transport if the transport's congestion window allows it.
*/
void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
{
if (xprt->snd_task == task) {
xprt_clear_locked(xprt);
__xprt_lock_write_next_cong(xprt);
}
}
static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
{
spin_lock_bh(&xprt->transport_lock);
xprt->ops->release_xprt(xprt, task);
spin_unlock_bh(&xprt->transport_lock);
}
/*
* 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_cong(xprt);
}
/**
* xprt_release_rqst_cong - housekeeping when request is complete
* @task: RPC request that recently completed
*
* Useful for transports that require congestion control.
*/
void xprt_release_rqst_cong(struct rpc_task *task)
{
__xprt_put_cong(task->tk_xprt, task->tk_rqstp);
}
/**
* xprt_adjust_cwnd - adjust transport congestion window
* @task: recently completed RPC request used to adjust window
* @result: result code of completed RPC request
*
* We use a time-smoothed congestion estimator to avoid heavy oscillation.
*/
void xprt_adjust_cwnd(struct rpc_task *task, int result)
{
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = task->tk_xprt;
unsigned long 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_cong(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;
__xprt_put_cong(xprt, req);
}
/**
* xprt_wake_pending_tasks - wake all tasks on a transport's pending queue
* @xprt: transport with waiting tasks
* @status: result code to plant in each task before waking it
*
*/
void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status)
{
if (status < 0)
rpc_wake_up_status(&xprt->pending, status);
else
rpc_wake_up(&xprt->pending);
}
/**
* xprt_wait_for_buffer_space - wait for transport output buffer to clear
* @task: task to be put to sleep
*
*/
void xprt_wait_for_buffer_space(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
task->tk_timeout = req->rq_timeout;
rpc_sleep_on(&xprt->pending, task, NULL, NULL);
}
/**
* xprt_write_space - wake the task waiting for transport output buffer space
* @xprt: transport with waiting tasks
*
* Can be called in a soft IRQ context, so xprt_write_space never sleeps.
*/
void xprt_write_space(struct rpc_xprt *xprt)
{
if (unlikely(xprt->shutdown))
return;
spin_lock_bh(&xprt->transport_lock);
if (xprt->snd_task) {
dprintk("RPC: write space: waking waiting task on xprt %p\n",
xprt);
rpc_wake_up_task(xprt->snd_task);
}
spin_unlock_bh(&xprt->transport_lock);
}
/**
* xprt_set_retrans_timeout_def - set a request's retransmit timeout
* @task: task whose timeout is to be set
*
* Set a request's retransmit timeout based on the transport's
* default timeout parameters. Used by transports that don't adjust
* the retransmit timeout based on round-trip time estimation.
*/
void xprt_set_retrans_timeout_def(struct rpc_task *task)
{
task->tk_timeout = task->tk_rqstp->rq_timeout;
}
/*
* xprt_set_retrans_timeout_rtt - set a request's retransmit timeout
* @task: task whose timeout is to be set
*
* Set a request's retransmit timeout using the RTT estimator.
*/
void xprt_set_retrans_timeout_rtt(struct rpc_task *task)
{
int timer = task->tk_msg.rpc_proc->p_timer;
struct rpc_rtt *rtt = task->tk_client->cl_rtt;
struct rpc_rqst *req = task->tk_rqstp;
unsigned long max_timeout = req->rq_xprt->timeout.to_maxval;
task->tk_timeout = rpc_calc_rto(rtt, timer);
task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries;
if (task->tk_timeout > max_timeout || task->tk_timeout == 0)
task->tk_timeout = max_timeout;
}
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;
}
/**
* xprt_adjust_timeout - adjust timeout values for next retransmit
* @req: RPC request containing parameters to use for the adjustment
*
*/
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->transport_lock);
rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
spin_unlock_bh(&xprt->transport_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;
}
static void xprt_autoclose(void *args)
{
struct rpc_xprt *xprt = (struct rpc_xprt *)args;
xprt_disconnect(xprt);
xprt->ops->close(xprt);
xprt_release_write(xprt, NULL);
}
/**
* xprt_disconnect - mark a transport as disconnected
* @xprt: transport to flag for disconnect
*
*/
void xprt_disconnect(struct rpc_xprt *xprt)
{
dprintk("RPC: disconnected transport %p\n", xprt);
spin_lock_bh(&xprt->transport_lock);
xprt_clear_connected(xprt);
xprt_wake_pending_tasks(xprt, -ENOTCONN);
spin_unlock_bh(&xprt->transport_lock);
}
static void
xprt_init_autodisconnect(unsigned long data)
{
struct rpc_xprt *xprt = (struct rpc_xprt *)data;
spin_lock(&xprt->transport_lock);
if (!list_empty(&xprt->recv) || xprt->shutdown)
goto out_abort;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
goto out_abort;
spin_unlock(&xprt->transport_lock);
if (xprt_connecting(xprt))
xprt_release_write(xprt, NULL);
else
schedule_work(&xprt->task_cleanup);
return;
out_abort:
spin_unlock(&xprt->transport_lock);
}
/**
* xprt_connect - schedule a transport connect operation
* @task: RPC task that is requesting the connect
*
*/
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->addr.sin_port) {
task->tk_status = -EIO;
return;
}
if (!xprt_lock_write(xprt, task))
return;
if (xprt_connected(xprt))
xprt_release_write(xprt, task);
else {
if (task->tk_rqstp)
task->tk_rqstp->rq_bytes_sent = 0;
task->tk_timeout = xprt->connect_timeout;
rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL);
xprt->ops->connect(task);
}
return;
}
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;
}
switch (task->tk_status) {
case -ECONNREFUSED:
case -ECONNRESET:
dprintk("RPC: %4d xprt_connect_status: server %s refused connection\n",
task->tk_pid, task->tk_client->cl_server);
break;
case -ENOTCONN:
dprintk("RPC: %4d xprt_connect_status: connection broken\n",
task->tk_pid);
break;
case -ETIMEDOUT:
dprintk("RPC: %4d xprt_connect_status: connect attempt timed out\n",
task->tk_pid);
break;
default:
dprintk("RPC: %4d xprt_connect_status: error %d connecting to server %s\n",
task->tk_pid, -task->tk_status, task->tk_client->cl_server);
xprt_release_write(xprt, task);
task->tk_status = -EIO;
return;
}
/* if soft mounted, just cause this RPC to fail */
if (RPC_IS_SOFT(task)) {
xprt_release_write(xprt, task);
task->tk_status = -EIO;
}
}
/**
* xprt_lookup_rqst - find an RPC request corresponding to an XID
* @xprt: transport on which the original request was transmitted
* @xid: RPC XID of incoming reply
*
*/
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;
}
/**
* xprt_update_rtt - update an RPC client's RTT state after receiving a reply
* @task: RPC request that recently completed
*
*/
void xprt_update_rtt(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_rtt *rtt = task->tk_client->cl_rtt;
unsigned timer = task->tk_msg.rpc_proc->p_timer;
if (timer) {
if (req->rq_ntrans == 1)
rpc_update_rtt(rtt, timer,
(long)jiffies - req->rq_xtime);
rpc_set_timeo(rtt, timer, req->rq_ntrans - 1);
}
}
/**
* xprt_complete_rqst - called when reply processing is complete
* @task: RPC request that recently completed
* @copied: actual number of bytes received from the transport
*
* Caller holds transport lock.
*/
void xprt_complete_rqst(struct rpc_task *task, int copied)
{
struct rpc_rqst *req = task->tk_rqstp;
dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
task->tk_pid, ntohl(req->rq_xid), copied);
list_del_init(&req->rq_list);
req->rq_received = req->rq_private_buf.len = copied;
rpc_wake_up_task(task);
}
static void xprt_timer(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
dprintk("RPC: %4d xprt_timer\n", task->tk_pid);
spin_lock(&xprt->transport_lock);
if (!req->rq_received) {
if (xprt->ops->timer)
xprt->ops->timer(task);
task->tk_status = -ETIMEDOUT;
}
task->tk_timeout = 0;
rpc_wake_up_task(task);
spin_unlock(&xprt->transport_lock);
}
/**
* xprt_prepare_transmit - reserve the transport before sending a request
* @task: RPC task about to send a request
*
*/
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);
spin_lock_bh(&xprt->transport_lock);
if (req->rq_received && !req->rq_bytes_sent) {
err = req->rq_received;
goto out_unlock;
}
if (!xprt->ops->reserve_xprt(task)) {
err = -EAGAIN;
goto out_unlock;
}
if (!xprt_connected(xprt)) {
err = -ENOTCONN;
goto out_unlock;
}
out_unlock:
spin_unlock_bh(&xprt->transport_lock);
return err;
}
void
xprt_abort_transmit(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
xprt_release_write(xprt, task);
}
/**
* xprt_transmit - send an RPC request on a transport
* @task: controlling RPC task
*
* 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;
int status;
dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
smp_rmb();
if (!req->rq_received) {
if (list_empty(&req->rq_list)) {
spin_lock_bh(&xprt->transport_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->transport_lock);
xprt_reset_majortimeo(req);
/* Turn off autodisconnect */
del_singleshot_timer_sync(&xprt->timer);
}
} else if (!req->rq_bytes_sent)
return;
status = xprt->ops->send_request(task);
if (status == 0) {
dprintk("RPC: %4d xmit complete\n", task->tk_pid);
spin_lock_bh(&xprt->transport_lock);
xprt->ops->set_retrans_timeout(task);
/* 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->ops->release_xprt(xprt, task);
spin_unlock_bh(&xprt->transport_lock);
return;
}
/* 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 -ECONNREFUSED:
rpc_sleep_on(&xprt->sending, task, NULL, NULL);
case -EAGAIN:
case -ENOTCONN:
return;
default:
break;
}
xprt_release_write(xprt, task);
return;
}
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);
}
/**
* xprt_reserve - allocate an RPC request slot
* @task: RPC task requesting a slot allocation
*
* If no more slots are available, place the task on the transport's
* backlog queue.
*/
void xprt_reserve(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
task->tk_status = -EIO;
spin_lock(&xprt->reserve_lock);
do_xprt_reserve(task);
spin_unlock(&xprt->reserve_lock);
}
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));
}
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_buffer = NULL;
req->rq_bufsize = 0;
req->rq_xid = xprt_alloc_xid(xprt);
req->rq_release_snd_buf = NULL;
dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
req, ntohl(req->rq_xid));
}
/**
* xprt_release - release an RPC request slot
* @task: task which is finished with the 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->transport_lock);
xprt->ops->release_xprt(xprt, task);
if (xprt->ops->release_request)
xprt->ops->release_request(task);
if (!list_empty(&req->rq_list))
list_del(&req->rq_list);
xprt->last_used = jiffies;
if (list_empty(&xprt->recv))
mod_timer(&xprt->timer,
xprt->last_used + xprt->idle_timeout);
spin_unlock_bh(&xprt->transport_lock);
xprt->ops->buf_free(task);
task->tk_rqstp = NULL;
if (req->rq_release_snd_buf)
req->rq_release_snd_buf(req);
memset(req, 0, sizeof(*req)); /* mark unused */
dprintk("RPC: %4d release request %p\n", task->tk_pid, req);
spin_lock(&xprt->reserve_lock);
list_add(&req->rq_list, &xprt->free);
rpc_wake_up_next(&xprt->backlog);
spin_unlock(&xprt->reserve_lock);
}
/**
* xprt_set_timeout - set constant RPC timeout
* @to: RPC timeout parameters to set up
* @retr: number of retries
* @incr: amount of increase after each retry
*
*/
void xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr)
{
to->to_initval =
to->to_increment = incr;
to->to_maxval = to->to_initval + (incr * retr);
to->to_retries = retr;
to->to_exponential = 0;
}
static struct rpc_xprt *xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to)
{
int result;
struct rpc_xprt *xprt;
struct rpc_rqst *req;
if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL)
return ERR_PTR(-ENOMEM);
memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */
xprt->addr = *ap;
switch (proto) {
case IPPROTO_UDP:
result = xs_setup_udp(xprt, to);
break;
case IPPROTO_TCP:
result = xs_setup_tcp(xprt, to);
break;
default:
printk(KERN_ERR "RPC: unrecognized transport protocol: %d\n",
proto);
result = -EIO;
break;
}
if (result) {
kfree(xprt);
return ERR_PTR(result);
}
spin_lock_init(&xprt->transport_lock);
spin_lock_init(&xprt->reserve_lock);
INIT_LIST_HEAD(&xprt->free);
INIT_LIST_HEAD(&xprt->recv);
INIT_WORK(&xprt->task_cleanup, xprt_autoclose, xprt);
init_timer(&xprt->timer);
xprt->timer.function = xprt_init_autodisconnect;
xprt->timer.data = (unsigned long) xprt;
xprt->last_used = jiffies;
xprt->cwnd = RPC_INITCWND;
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[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--)
list_add(&req->rq_list, &xprt->free);
xprt_init_xid(xprt);
dprintk("RPC: created transport %p with %u slots\n", xprt,
xprt->max_reqs);
return xprt;
}
/**
* xprt_create_proto - create an RPC client transport
* @proto: requested transport protocol
* @sap: remote peer's address
* @to: timeout parameters for new transport
*
*/
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;
}
/**
* xprt_destroy - destroy an RPC transport, killing off all requests.
* @xprt: transport to destroy
*
*/
int xprt_destroy(struct rpc_xprt *xprt)
{
dprintk("RPC: destroying transport %p\n", xprt);
xprt->shutdown = 1;
del_timer_sync(&xprt->timer);
xprt->ops->destroy(xprt);
kfree(xprt);
return 0;
}
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