linux/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
nfs41: Add backchannel processing support to RPC state machine Adds rpc_run_bc_task() which is called by the NFS callback service to process backchannel requests. It performs similar work to rpc_run_task() though "schedules" the backchannel task to be executed starting at the call_trasmit state in the RPC state machine. It also introduces some miscellaneous updates to the argument validation, call_transmit, and transport cleanup functions to take into account that there are now forechannel and backchannel tasks. Backchannel requests do not carry an RPC message structure, since the payload has already been XDR encoded using the existing NFSv4 callback mechanism. Introduce a new transmit state for the client to reply on to backchannel requests. This new state simply reserves the transport and issues the reply. In case of a connection related error, disconnects the transport and drops the reply. It requires the forechannel to re-establish the connection and the server to retransmit the request, as stated in NFSv4.1 section 2.9.2 "Client and Server Transport Behavior". Note: There is no need to loop attempting to reserve the transport. If EAGAIN is returned by xprt_prepare_transmit(), return with tk_status == 0, setting tk_action to call_bc_transmit. rpc_execute() will invoke it again after the task is taken off the sleep queue. [nfs41: rpc_run_bc_task() need not be exported outside RPC module] [nfs41: New call_bc_transmit RPC state] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: No need to loop in call_bc_transmit()] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [rpc_count_iostats incorrectly exits early] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Convert rpc_reply_expected() to inline function] [Remove unnecessary BUG_ON()] [Rename variable] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 13:23:03 +00:00
* transport's wait list. At the same time, if a reply is expected,
* 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/net.h>
#include <linux/ktime.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/metrics.h>
#include <linux/sunrpc/bc_xprt.h>
nfs41: Add backchannel processing support to RPC state machine Adds rpc_run_bc_task() which is called by the NFS callback service to process backchannel requests. It performs similar work to rpc_run_task() though "schedules" the backchannel task to be executed starting at the call_trasmit state in the RPC state machine. It also introduces some miscellaneous updates to the argument validation, call_transmit, and transport cleanup functions to take into account that there are now forechannel and backchannel tasks. Backchannel requests do not carry an RPC message structure, since the payload has already been XDR encoded using the existing NFSv4 callback mechanism. Introduce a new transmit state for the client to reply on to backchannel requests. This new state simply reserves the transport and issues the reply. In case of a connection related error, disconnects the transport and drops the reply. It requires the forechannel to re-establish the connection and the server to retransmit the request, as stated in NFSv4.1 section 2.9.2 "Client and Server Transport Behavior". Note: There is no need to loop attempting to reserve the transport. If EAGAIN is returned by xprt_prepare_transmit(), return with tk_status == 0, setting tk_action to call_bc_transmit. rpc_execute() will invoke it again after the task is taken off the sleep queue. [nfs41: rpc_run_bc_task() need not be exported outside RPC module] [nfs41: New call_bc_transmit RPC state] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: No need to loop in call_bc_transmit()] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [rpc_count_iostats incorrectly exits early] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Convert rpc_reply_expected() to inline function] [Remove unnecessary BUG_ON()] [Rename variable] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 13:23:03 +00:00
#include "sunrpc.h"
/*
* Local variables
*/
#ifdef RPC_DEBUG
# define RPCDBG_FACILITY RPCDBG_XPRT
#endif
/*
* Local functions
*/
static void xprt_init(struct rpc_xprt *xprt, struct net *net);
static void xprt_request_init(struct rpc_task *, struct rpc_xprt *);
static void xprt_connect_status(struct rpc_task *task);
static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
static DEFINE_SPINLOCK(xprt_list_lock);
static LIST_HEAD(xprt_list);
/*
* 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_register_transport - register a transport implementation
* @transport: transport to register
*
* If a transport implementation is loaded as a kernel module, it can
* call this interface to make itself known to the RPC client.
*
* Returns:
* 0: transport successfully registered
* -EEXIST: transport already registered
* -EINVAL: transport module being unloaded
*/
int xprt_register_transport(struct xprt_class *transport)
{
struct xprt_class *t;
int result;
result = -EEXIST;
spin_lock(&xprt_list_lock);
list_for_each_entry(t, &xprt_list, list) {
/* don't register the same transport class twice */
if (t->ident == transport->ident)
goto out;
}
list_add_tail(&transport->list, &xprt_list);
printk(KERN_INFO "RPC: Registered %s transport module.\n",
transport->name);
result = 0;
out:
spin_unlock(&xprt_list_lock);
return result;
}
EXPORT_SYMBOL_GPL(xprt_register_transport);
/**
* xprt_unregister_transport - unregister a transport implementation
* @transport: transport to unregister
*
* Returns:
* 0: transport successfully unregistered
* -ENOENT: transport never registered
*/
int xprt_unregister_transport(struct xprt_class *transport)
{
struct xprt_class *t;
int result;
result = 0;
spin_lock(&xprt_list_lock);
list_for_each_entry(t, &xprt_list, list) {
if (t == transport) {
printk(KERN_INFO
"RPC: Unregistered %s transport module.\n",
transport->name);
list_del_init(&transport->list);
goto out;
}
}
result = -ENOENT;
out:
spin_unlock(&xprt_list_lock);
return result;
}
EXPORT_SYMBOL_GPL(xprt_unregister_transport);
/**
* xprt_load_transport - load a transport implementation
* @transport_name: transport to load
*
* Returns:
* 0: transport successfully loaded
* -ENOENT: transport module not available
*/
int xprt_load_transport(const char *transport_name)
{
struct xprt_class *t;
int result;
result = 0;
spin_lock(&xprt_list_lock);
list_for_each_entry(t, &xprt_list, list) {
if (strcmp(t->name, transport_name) == 0) {
spin_unlock(&xprt_list_lock);
goto out;
}
}
spin_unlock(&xprt_list_lock);
result = request_module("xprt%s", transport_name);
out:
return result;
}
EXPORT_SYMBOL_GPL(xprt_load_transport);
/**
* xprt_reserve_xprt - serialize write access to transports
* @task: task that is requesting access to the transport
* @xprt: pointer to the target 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_xprt *xprt, struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
int priority;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
if (task == xprt->snd_task)
return 1;
goto out_sleep;
}
xprt->snd_task = task;
if (req != NULL) {
req->rq_bytes_sent = 0;
req->rq_ntrans++;
}
return 1;
out_sleep:
dprintk("RPC: %5u failed to lock transport %p\n",
task->tk_pid, xprt);
task->tk_timeout = 0;
task->tk_status = -EAGAIN;
if (req == NULL)
priority = RPC_PRIORITY_LOW;
else if (!req->rq_ntrans)
priority = RPC_PRIORITY_NORMAL;
else
priority = RPC_PRIORITY_HIGH;
rpc_sleep_on_priority(&xprt->sending, task, NULL, priority);
return 0;
}
EXPORT_SYMBOL_GPL(xprt_reserve_xprt);
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
queue_work(rpciod_workqueue, &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_xprt *xprt, struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
int priority;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
if (task == xprt->snd_task)
return 1;
goto out_sleep;
}
if (req == NULL) {
xprt->snd_task = task;
return 1;
}
if (__xprt_get_cong(xprt, task)) {
xprt->snd_task = task;
req->rq_bytes_sent = 0;
req->rq_ntrans++;
return 1;
}
xprt_clear_locked(xprt);
out_sleep:
dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt);
task->tk_timeout = 0;
task->tk_status = -EAGAIN;
if (req == NULL)
priority = RPC_PRIORITY_LOW;
else if (!req->rq_ntrans)
priority = RPC_PRIORITY_NORMAL;
else
priority = RPC_PRIORITY_HIGH;
rpc_sleep_on_priority(&xprt->sending, task, NULL, priority);
return 0;
}
EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong);
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(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->sending);
if (task == NULL)
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;
struct rpc_rqst *req;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
return;
if (RPCXPRT_CONGESTED(xprt))
goto out_unlock;
task = rpc_wake_up_next(&xprt->sending);
if (task == NULL)
goto out_unlock;
req = task->tk_rqstp;
if (req == NULL) {
xprt->snd_task = task;
return;
}
if (__xprt_get_cong(xprt, task)) {
xprt->snd_task = task;
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);
}
}
EXPORT_SYMBOL_GPL(xprt_release_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);
}
}
EXPORT_SYMBOL_GPL(xprt_release_xprt_cong);
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: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\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);
}
EXPORT_SYMBOL_GPL(xprt_release_rqst_cong);
/**
* 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);
}
EXPORT_SYMBOL_GPL(xprt_adjust_cwnd);
/**
* 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);
}
EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks);
/**
* xprt_wait_for_buffer_space - wait for transport output buffer to clear
* @task: task to be put to sleep
* @action: function pointer to be executed after wait
*/
void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action)
{
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, action);
}
EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space);
/**
* 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_queued_task(&xprt->pending, xprt->snd_task);
}
spin_unlock_bh(&xprt->transport_lock);
}
EXPORT_SYMBOL_GPL(xprt_write_space);
/**
* 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;
}
EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def);
/*
* 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_clnt *clnt = task->tk_client;
struct rpc_rtt *rtt = clnt->cl_rtt;
struct rpc_rqst *req = task->tk_rqstp;
unsigned long max_timeout = clnt->cl_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;
}
EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_rtt);
static void xprt_reset_majortimeo(struct rpc_rqst *req)
{
const struct rpc_timeout *to = req->rq_task->tk_client->cl_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;
const struct rpc_timeout *to = req->rq_task->tk_client->cl_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++;
} 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);
status = -ETIMEDOUT;
}
if (req->rq_timeout == 0) {
printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n");
req->rq_timeout = 5 * HZ;
}
return status;
}
2006-11-22 14:55:48 +00:00
static void xprt_autoclose(struct work_struct *work)
{
2006-11-22 14:55:48 +00:00
struct rpc_xprt *xprt =
container_of(work, struct rpc_xprt, task_cleanup);
xprt->ops->close(xprt);
clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
xprt_release_write(xprt, NULL);
}
/**
* xprt_disconnect_done - mark a transport as disconnected
* @xprt: transport to flag for disconnect
*
*/
void xprt_disconnect_done(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, -EAGAIN);
spin_unlock_bh(&xprt->transport_lock);
}
EXPORT_SYMBOL_GPL(xprt_disconnect_done);
/**
* xprt_force_disconnect - force a transport to disconnect
* @xprt: transport to disconnect
*
*/
void xprt_force_disconnect(struct rpc_xprt *xprt)
{
/* Don't race with the test_bit() in xprt_clear_locked() */
spin_lock_bh(&xprt->transport_lock);
set_bit(XPRT_CLOSE_WAIT, &xprt->state);
/* Try to schedule an autoclose RPC call */
if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
queue_work(rpciod_workqueue, &xprt->task_cleanup);
xprt_wake_pending_tasks(xprt, -EAGAIN);
spin_unlock_bh(&xprt->transport_lock);
}
/**
* xprt_conditional_disconnect - force a transport to disconnect
* @xprt: transport to disconnect
* @cookie: 'connection cookie'
*
* This attempts to break the connection if and only if 'cookie' matches
* the current transport 'connection cookie'. It ensures that we don't
* try to break the connection more than once when we need to retransmit
* a batch of RPC requests.
*
*/
void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie)
{
/* Don't race with the test_bit() in xprt_clear_locked() */
spin_lock_bh(&xprt->transport_lock);
if (cookie != xprt->connect_cookie)
goto out;
if (test_bit(XPRT_CLOSING, &xprt->state) || !xprt_connected(xprt))
goto out;
set_bit(XPRT_CLOSE_WAIT, &xprt->state);
/* Try to schedule an autoclose RPC call */
if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
queue_work(rpciod_workqueue, &xprt->task_cleanup);
xprt_wake_pending_tasks(xprt, -EAGAIN);
out:
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);
set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
queue_work(rpciod_workqueue, &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: %5u xprt_connect xprt %p %s connected\n", task->tk_pid,
xprt, (xprt_connected(xprt) ? "is" : "is not"));
if (!xprt_bound(xprt)) {
task->tk_status = -EAGAIN;
return;
}
if (!xprt_lock_write(xprt, task))
return;
if (test_and_clear_bit(XPRT_CLOSE_WAIT, &xprt->state))
xprt->ops->close(xprt);
if (xprt_connected(xprt))
xprt_release_write(xprt, task);
else {
if (task->tk_rqstp)
task->tk_rqstp->rq_bytes_sent = 0;
task->tk_timeout = task->tk_rqstp->rq_timeout;
rpc_sleep_on(&xprt->pending, task, xprt_connect_status);
if (test_bit(XPRT_CLOSING, &xprt->state))
return;
if (xprt_test_and_set_connecting(xprt))
return;
xprt->stat.connect_start = jiffies;
xprt->ops->connect(task);
}
}
static void xprt_connect_status(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
if (task->tk_status == 0) {
xprt->stat.connect_count++;
xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start;
dprintk("RPC: %5u xprt_connect_status: connection established\n",
task->tk_pid);
return;
}
switch (task->tk_status) {
case -EAGAIN:
dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid);
break;
case -ETIMEDOUT:
dprintk("RPC: %5u xprt_connect_status: connect attempt timed "
"out\n", task->tk_pid);
break;
default:
dprintk("RPC: %5u 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;
}
}
/**
* 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, __be32 xid)
{
struct rpc_rqst *entry;
list_for_each_entry(entry, &xprt->recv, rq_list)
if (entry->rq_xid == xid)
return entry;
dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n",
ntohl(xid));
xprt->stat.bad_xids++;
return NULL;
}
EXPORT_SYMBOL_GPL(xprt_lookup_rqst);
static 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;
long m = usecs_to_jiffies(ktime_to_us(req->rq_rtt));
if (timer) {
if (req->rq_ntrans == 1)
rpc_update_rtt(rtt, timer, m);
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;
struct rpc_xprt *xprt = req->rq_xprt;
dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
task->tk_pid, ntohl(req->rq_xid), copied);
xprt->stat.recvs++;
req->rq_rtt = ktime_sub(ktime_get(), req->rq_xtime);
if (xprt->ops->timer != NULL)
xprt_update_rtt(task);
list_del_init(&req->rq_list);
req->rq_private_buf.len = copied;
/* Ensure all writes are done before we update */
/* req->rq_reply_bytes_recvd */
smp_wmb();
req->rq_reply_bytes_recvd = copied;
rpc_wake_up_queued_task(&xprt->pending, task);
}
EXPORT_SYMBOL_GPL(xprt_complete_rqst);
static void xprt_timer(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
if (task->tk_status != -ETIMEDOUT)
return;
dprintk("RPC: %5u xprt_timer\n", task->tk_pid);
spin_lock_bh(&xprt->transport_lock);
if (!req->rq_reply_bytes_recvd) {
if (xprt->ops->timer)
xprt->ops->timer(task);
} else
task->tk_status = 0;
spin_unlock_bh(&xprt->transport_lock);
}
nfsd41: sunrpc: Added rpc server-side backchannel handling When the call direction is a reply, copy the xid and call direction into the req->rq_private_buf.head[0].iov_base otherwise rpc_verify_header returns rpc_garbage. Signed-off-by: Rahul Iyer <iyer@netapp.com> Signed-off-by: Mike Sager <sager@netapp.com> Signed-off-by: Marc Eshel <eshel@almaden.ibm.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [get rid of CONFIG_NFSD_V4_1] [sunrpc: refactoring of svc_tcp_recvfrom] [nfsd41: sunrpc: create common send routine for the fore and the back channels] [nfsd41: sunrpc: Use free_page() to free server backchannel pages] [nfsd41: sunrpc: Document server backchannel locking] [nfsd41: sunrpc: remove bc_connect_worker()] [nfsd41: sunrpc: Define xprt_server_backchannel()[ [nfsd41: sunrpc: remove bc_close and bc_init_auto_disconnect dummy functions] [nfsd41: sunrpc: eliminate unneeded switch statement in xs_setup_tcp()] [nfsd41: sunrpc: Don't auto close the server backchannel connection] [nfsd41: sunrpc: Remove unused functions] Signed-off-by: Alexandros Batsakis <batsakis@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfsd41: change bc_sock to bc_xprt] [nfsd41: sunrpc: move struct rpc_buffer def into a common header file] [nfsd41: sunrpc: use rpc_sleep in bc_send_request so not to block on mutex] [removed cosmetic changes] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [sunrpc: add new xprt class for nfsv4.1 backchannel] [sunrpc: v2.1 change handling of auto_close and init_auto_disconnect operations for the nfsv4.1 backchannel] Signed-off-by: Alexandros Batsakis <batsakis@netapp.com> [reverted more cosmetic leftovers] [got rid of xprt_server_backchannel] [separated "nfsd41: sunrpc: add new xprt class for nfsv4.1 backchannel"] Signed-off-by: Benny Halevy <bhalevy@panasas.com> Cc: Trond Myklebust <trond.myklebust@netapp.com> [sunrpc: change idle timeout value for the backchannel] Signed-off-by: Alexandros Batsakis <batsakis@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Acked-by: Trond Myklebust <trond.myklebust@netapp.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-09-10 14:32:28 +00:00
static inline int xprt_has_timer(struct rpc_xprt *xprt)
{
return xprt->idle_timeout != 0;
}
/**
* 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: %5u xprt_prepare_transmit\n", task->tk_pid);
spin_lock_bh(&xprt->transport_lock);
if (req->rq_reply_bytes_recvd && !req->rq_bytes_sent) {
err = req->rq_reply_bytes_recvd;
goto out_unlock;
}
if (!xprt->ops->reserve_xprt(xprt, task))
err = -EAGAIN;
out_unlock:
spin_unlock_bh(&xprt->transport_lock);
return err;
}
void xprt_end_transmit(struct rpc_task *task)
{
xprt_release_write(task->tk_rqstp->rq_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: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
if (!req->rq_reply_bytes_recvd) {
nfs41: Add backchannel processing support to RPC state machine Adds rpc_run_bc_task() which is called by the NFS callback service to process backchannel requests. It performs similar work to rpc_run_task() though "schedules" the backchannel task to be executed starting at the call_trasmit state in the RPC state machine. It also introduces some miscellaneous updates to the argument validation, call_transmit, and transport cleanup functions to take into account that there are now forechannel and backchannel tasks. Backchannel requests do not carry an RPC message structure, since the payload has already been XDR encoded using the existing NFSv4 callback mechanism. Introduce a new transmit state for the client to reply on to backchannel requests. This new state simply reserves the transport and issues the reply. In case of a connection related error, disconnects the transport and drops the reply. It requires the forechannel to re-establish the connection and the server to retransmit the request, as stated in NFSv4.1 section 2.9.2 "Client and Server Transport Behavior". Note: There is no need to loop attempting to reserve the transport. If EAGAIN is returned by xprt_prepare_transmit(), return with tk_status == 0, setting tk_action to call_bc_transmit. rpc_execute() will invoke it again after the task is taken off the sleep queue. [nfs41: rpc_run_bc_task() need not be exported outside RPC module] [nfs41: New call_bc_transmit RPC state] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: No need to loop in call_bc_transmit()] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [rpc_count_iostats incorrectly exits early] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Convert rpc_reply_expected() to inline function] [Remove unnecessary BUG_ON()] [Rename variable] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 13:23:03 +00:00
if (list_empty(&req->rq_list) && rpc_reply_expected(task)) {
/*
* Add to the list only if we're expecting a reply
*/
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;
req->rq_connect_cookie = xprt->connect_cookie;
req->rq_xtime = ktime_get();
status = xprt->ops->send_request(task);
if (status != 0) {
task->tk_status = status;
return;
}
dprintk("RPC: %5u xmit complete\n", task->tk_pid);
task->tk_flags |= RPC_TASK_SENT;
spin_lock_bh(&xprt->transport_lock);
xprt->ops->set_retrans_timeout(task);
xprt->stat.sends++;
xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs;
xprt->stat.bklog_u += xprt->backlog.qlen;
/* Don't race with disconnect */
if (!xprt_connected(xprt))
task->tk_status = -ENOTCONN;
else if (!req->rq_reply_bytes_recvd && rpc_reply_expected(task)) {
nfs41: Add backchannel processing support to RPC state machine Adds rpc_run_bc_task() which is called by the NFS callback service to process backchannel requests. It performs similar work to rpc_run_task() though "schedules" the backchannel task to be executed starting at the call_trasmit state in the RPC state machine. It also introduces some miscellaneous updates to the argument validation, call_transmit, and transport cleanup functions to take into account that there are now forechannel and backchannel tasks. Backchannel requests do not carry an RPC message structure, since the payload has already been XDR encoded using the existing NFSv4 callback mechanism. Introduce a new transmit state for the client to reply on to backchannel requests. This new state simply reserves the transport and issues the reply. In case of a connection related error, disconnects the transport and drops the reply. It requires the forechannel to re-establish the connection and the server to retransmit the request, as stated in NFSv4.1 section 2.9.2 "Client and Server Transport Behavior". Note: There is no need to loop attempting to reserve the transport. If EAGAIN is returned by xprt_prepare_transmit(), return with tk_status == 0, setting tk_action to call_bc_transmit. rpc_execute() will invoke it again after the task is taken off the sleep queue. [nfs41: rpc_run_bc_task() need not be exported outside RPC module] [nfs41: New call_bc_transmit RPC state] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: No need to loop in call_bc_transmit()] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [rpc_count_iostats incorrectly exits early] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Convert rpc_reply_expected() to inline function] [Remove unnecessary BUG_ON()] [Rename variable] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 13:23:03 +00:00
/*
* Sleep on the pending queue since
* we're expecting a reply.
*/
rpc_sleep_on(&xprt->pending, task, xprt_timer);
nfs41: Add backchannel processing support to RPC state machine Adds rpc_run_bc_task() which is called by the NFS callback service to process backchannel requests. It performs similar work to rpc_run_task() though "schedules" the backchannel task to be executed starting at the call_trasmit state in the RPC state machine. It also introduces some miscellaneous updates to the argument validation, call_transmit, and transport cleanup functions to take into account that there are now forechannel and backchannel tasks. Backchannel requests do not carry an RPC message structure, since the payload has already been XDR encoded using the existing NFSv4 callback mechanism. Introduce a new transmit state for the client to reply on to backchannel requests. This new state simply reserves the transport and issues the reply. In case of a connection related error, disconnects the transport and drops the reply. It requires the forechannel to re-establish the connection and the server to retransmit the request, as stated in NFSv4.1 section 2.9.2 "Client and Server Transport Behavior". Note: There is no need to loop attempting to reserve the transport. If EAGAIN is returned by xprt_prepare_transmit(), return with tk_status == 0, setting tk_action to call_bc_transmit. rpc_execute() will invoke it again after the task is taken off the sleep queue. [nfs41: rpc_run_bc_task() need not be exported outside RPC module] [nfs41: New call_bc_transmit RPC state] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: No need to loop in call_bc_transmit()] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [rpc_count_iostats incorrectly exits early] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Convert rpc_reply_expected() to inline function] [Remove unnecessary BUG_ON()] [Rename variable] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 13:23:03 +00:00
}
spin_unlock_bh(&xprt->transport_lock);
}
static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt, gfp_t gfp_flags)
{
struct rpc_rqst *req = ERR_PTR(-EAGAIN);
if (!atomic_add_unless(&xprt->num_reqs, 1, xprt->max_reqs))
goto out;
req = kzalloc(sizeof(struct rpc_rqst), gfp_flags);
if (req != NULL)
goto out;
atomic_dec(&xprt->num_reqs);
req = ERR_PTR(-ENOMEM);
out:
return req;
}
static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
{
if (atomic_add_unless(&xprt->num_reqs, -1, xprt->min_reqs)) {
kfree(req);
return true;
}
return false;
}
static void xprt_alloc_slot(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
struct rpc_rqst *req;
if (!list_empty(&xprt->free)) {
req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
list_del(&req->rq_list);
goto out_init_req;
}
req = xprt_dynamic_alloc_slot(xprt, GFP_NOWAIT);
if (!IS_ERR(req))
goto out_init_req;
switch (PTR_ERR(req)) {
case -ENOMEM:
rpc_delay(task, HZ >> 2);
dprintk("RPC: dynamic allocation of request slot "
"failed! Retrying\n");
break;
case -EAGAIN:
rpc_sleep_on(&xprt->backlog, task, NULL);
dprintk("RPC: waiting for request slot\n");
}
task->tk_status = -EAGAIN;
return;
out_init_req:
task->tk_status = 0;
task->tk_rqstp = req;
xprt_request_init(task, xprt);
}
static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
{
if (xprt_dynamic_free_slot(xprt, req))
return;
memset(req, 0, sizeof(*req)); /* mark unused */
spin_lock(&xprt->reserve_lock);
list_add(&req->rq_list, &xprt->free);
rpc_wake_up_next(&xprt->backlog);
spin_unlock(&xprt->reserve_lock);
}
static void xprt_free_all_slots(struct rpc_xprt *xprt)
{
struct rpc_rqst *req;
while (!list_empty(&xprt->free)) {
req = list_first_entry(&xprt->free, struct rpc_rqst, rq_list);
list_del(&req->rq_list);
kfree(req);
}
}
struct rpc_xprt *xprt_alloc(struct net *net, size_t size,
unsigned int num_prealloc,
unsigned int max_alloc)
{
struct rpc_xprt *xprt;
struct rpc_rqst *req;
int i;
xprt = kzalloc(size, GFP_KERNEL);
if (xprt == NULL)
goto out;
xprt_init(xprt, net);
for (i = 0; i < num_prealloc; i++) {
req = kzalloc(sizeof(struct rpc_rqst), GFP_KERNEL);
if (!req)
break;
list_add(&req->rq_list, &xprt->free);
}
if (i < num_prealloc)
goto out_free;
if (max_alloc > num_prealloc)
xprt->max_reqs = max_alloc;
else
xprt->max_reqs = num_prealloc;
xprt->min_reqs = num_prealloc;
atomic_set(&xprt->num_reqs, num_prealloc);
return xprt;
out_free:
xprt_free(xprt);
out:
return NULL;
}
EXPORT_SYMBOL_GPL(xprt_alloc);
void xprt_free(struct rpc_xprt *xprt)
{
put_net(xprt->xprt_net);
xprt_free_all_slots(xprt);
kfree(xprt);
}
EXPORT_SYMBOL_GPL(xprt_free);
/**
* 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 = 0;
if (task->tk_rqstp != NULL)
return;
/* Note: grabbing the xprt_lock_write() here is not strictly needed,
* but ensures that we throttle new slot allocation if the transport
* is congested (e.g. if reconnecting or if we're out of socket
* write buffer space).
*/
task->tk_timeout = 0;
task->tk_status = -EAGAIN;
if (!xprt_lock_write(xprt, task))
return;
spin_lock(&xprt->reserve_lock);
xprt_alloc_slot(task);
spin_unlock(&xprt->reserve_lock);
xprt_release_write(xprt, task);
}
static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)
{
return (__force __be32)xprt->xid++;
}
static inline void xprt_init_xid(struct rpc_xprt *xprt)
{
xprt->xid = net_random();
}
static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
{
struct rpc_rqst *req = task->tk_rqstp;
INIT_LIST_HEAD(&req->rq_list);
req->rq_timeout = task->tk_client->cl_timeout->to_initval;
req->rq_task = task;
req->rq_xprt = xprt;
req->rq_buffer = NULL;
req->rq_xid = xprt_alloc_xid(xprt);
req->rq_release_snd_buf = NULL;
xprt_reset_majortimeo(req);
dprintk("RPC: %5u 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)
{
nfs41: Add backchannel processing support to RPC state machine Adds rpc_run_bc_task() which is called by the NFS callback service to process backchannel requests. It performs similar work to rpc_run_task() though "schedules" the backchannel task to be executed starting at the call_trasmit state in the RPC state machine. It also introduces some miscellaneous updates to the argument validation, call_transmit, and transport cleanup functions to take into account that there are now forechannel and backchannel tasks. Backchannel requests do not carry an RPC message structure, since the payload has already been XDR encoded using the existing NFSv4 callback mechanism. Introduce a new transmit state for the client to reply on to backchannel requests. This new state simply reserves the transport and issues the reply. In case of a connection related error, disconnects the transport and drops the reply. It requires the forechannel to re-establish the connection and the server to retransmit the request, as stated in NFSv4.1 section 2.9.2 "Client and Server Transport Behavior". Note: There is no need to loop attempting to reserve the transport. If EAGAIN is returned by xprt_prepare_transmit(), return with tk_status == 0, setting tk_action to call_bc_transmit. rpc_execute() will invoke it again after the task is taken off the sleep queue. [nfs41: rpc_run_bc_task() need not be exported outside RPC module] [nfs41: New call_bc_transmit RPC state] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: No need to loop in call_bc_transmit()] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [rpc_count_iostats incorrectly exits early] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Convert rpc_reply_expected() to inline function] [Remove unnecessary BUG_ON()] [Rename variable] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 13:23:03 +00:00
struct rpc_xprt *xprt;
struct rpc_rqst *req;
if (!(req = task->tk_rqstp))
return;
nfs41: Add backchannel processing support to RPC state machine Adds rpc_run_bc_task() which is called by the NFS callback service to process backchannel requests. It performs similar work to rpc_run_task() though "schedules" the backchannel task to be executed starting at the call_trasmit state in the RPC state machine. It also introduces some miscellaneous updates to the argument validation, call_transmit, and transport cleanup functions to take into account that there are now forechannel and backchannel tasks. Backchannel requests do not carry an RPC message structure, since the payload has already been XDR encoded using the existing NFSv4 callback mechanism. Introduce a new transmit state for the client to reply on to backchannel requests. This new state simply reserves the transport and issues the reply. In case of a connection related error, disconnects the transport and drops the reply. It requires the forechannel to re-establish the connection and the server to retransmit the request, as stated in NFSv4.1 section 2.9.2 "Client and Server Transport Behavior". Note: There is no need to loop attempting to reserve the transport. If EAGAIN is returned by xprt_prepare_transmit(), return with tk_status == 0, setting tk_action to call_bc_transmit. rpc_execute() will invoke it again after the task is taken off the sleep queue. [nfs41: rpc_run_bc_task() need not be exported outside RPC module] [nfs41: New call_bc_transmit RPC state] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: No need to loop in call_bc_transmit()] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [rpc_count_iostats incorrectly exits early] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Convert rpc_reply_expected() to inline function] [Remove unnecessary BUG_ON()] [Rename variable] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 13:23:03 +00:00
xprt = req->rq_xprt;
rpc_count_iostats(task);
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;
nfsd41: sunrpc: Added rpc server-side backchannel handling When the call direction is a reply, copy the xid and call direction into the req->rq_private_buf.head[0].iov_base otherwise rpc_verify_header returns rpc_garbage. Signed-off-by: Rahul Iyer <iyer@netapp.com> Signed-off-by: Mike Sager <sager@netapp.com> Signed-off-by: Marc Eshel <eshel@almaden.ibm.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [get rid of CONFIG_NFSD_V4_1] [sunrpc: refactoring of svc_tcp_recvfrom] [nfsd41: sunrpc: create common send routine for the fore and the back channels] [nfsd41: sunrpc: Use free_page() to free server backchannel pages] [nfsd41: sunrpc: Document server backchannel locking] [nfsd41: sunrpc: remove bc_connect_worker()] [nfsd41: sunrpc: Define xprt_server_backchannel()[ [nfsd41: sunrpc: remove bc_close and bc_init_auto_disconnect dummy functions] [nfsd41: sunrpc: eliminate unneeded switch statement in xs_setup_tcp()] [nfsd41: sunrpc: Don't auto close the server backchannel connection] [nfsd41: sunrpc: Remove unused functions] Signed-off-by: Alexandros Batsakis <batsakis@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfsd41: change bc_sock to bc_xprt] [nfsd41: sunrpc: move struct rpc_buffer def into a common header file] [nfsd41: sunrpc: use rpc_sleep in bc_send_request so not to block on mutex] [removed cosmetic changes] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [sunrpc: add new xprt class for nfsv4.1 backchannel] [sunrpc: v2.1 change handling of auto_close and init_auto_disconnect operations for the nfsv4.1 backchannel] Signed-off-by: Alexandros Batsakis <batsakis@netapp.com> [reverted more cosmetic leftovers] [got rid of xprt_server_backchannel] [separated "nfsd41: sunrpc: add new xprt class for nfsv4.1 backchannel"] Signed-off-by: Benny Halevy <bhalevy@panasas.com> Cc: Trond Myklebust <trond.myklebust@netapp.com> [sunrpc: change idle timeout value for the backchannel] Signed-off-by: Alexandros Batsakis <batsakis@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Acked-by: Trond Myklebust <trond.myklebust@netapp.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-09-10 14:32:28 +00:00
if (list_empty(&xprt->recv) && xprt_has_timer(xprt))
mod_timer(&xprt->timer,
xprt->last_used + xprt->idle_timeout);
spin_unlock_bh(&xprt->transport_lock);
if (req->rq_buffer)
nfs41: Add backchannel processing support to RPC state machine Adds rpc_run_bc_task() which is called by the NFS callback service to process backchannel requests. It performs similar work to rpc_run_task() though "schedules" the backchannel task to be executed starting at the call_trasmit state in the RPC state machine. It also introduces some miscellaneous updates to the argument validation, call_transmit, and transport cleanup functions to take into account that there are now forechannel and backchannel tasks. Backchannel requests do not carry an RPC message structure, since the payload has already been XDR encoded using the existing NFSv4 callback mechanism. Introduce a new transmit state for the client to reply on to backchannel requests. This new state simply reserves the transport and issues the reply. In case of a connection related error, disconnects the transport and drops the reply. It requires the forechannel to re-establish the connection and the server to retransmit the request, as stated in NFSv4.1 section 2.9.2 "Client and Server Transport Behavior". Note: There is no need to loop attempting to reserve the transport. If EAGAIN is returned by xprt_prepare_transmit(), return with tk_status == 0, setting tk_action to call_bc_transmit. rpc_execute() will invoke it again after the task is taken off the sleep queue. [nfs41: rpc_run_bc_task() need not be exported outside RPC module] [nfs41: New call_bc_transmit RPC state] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: No need to loop in call_bc_transmit()] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [rpc_count_iostats incorrectly exits early] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Convert rpc_reply_expected() to inline function] [Remove unnecessary BUG_ON()] [Rename variable] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 13:23:03 +00:00
xprt->ops->buf_free(req->rq_buffer);
if (req->rq_cred != NULL)
put_rpccred(req->rq_cred);
task->tk_rqstp = NULL;
if (req->rq_release_snd_buf)
req->rq_release_snd_buf(req);
nfs41: Add backchannel processing support to RPC state machine Adds rpc_run_bc_task() which is called by the NFS callback service to process backchannel requests. It performs similar work to rpc_run_task() though "schedules" the backchannel task to be executed starting at the call_trasmit state in the RPC state machine. It also introduces some miscellaneous updates to the argument validation, call_transmit, and transport cleanup functions to take into account that there are now forechannel and backchannel tasks. Backchannel requests do not carry an RPC message structure, since the payload has already been XDR encoded using the existing NFSv4 callback mechanism. Introduce a new transmit state for the client to reply on to backchannel requests. This new state simply reserves the transport and issues the reply. In case of a connection related error, disconnects the transport and drops the reply. It requires the forechannel to re-establish the connection and the server to retransmit the request, as stated in NFSv4.1 section 2.9.2 "Client and Server Transport Behavior". Note: There is no need to loop attempting to reserve the transport. If EAGAIN is returned by xprt_prepare_transmit(), return with tk_status == 0, setting tk_action to call_bc_transmit. rpc_execute() will invoke it again after the task is taken off the sleep queue. [nfs41: rpc_run_bc_task() need not be exported outside RPC module] [nfs41: New call_bc_transmit RPC state] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: No need to loop in call_bc_transmit()] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [rpc_count_iostats incorrectly exits early] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Convert rpc_reply_expected() to inline function] [Remove unnecessary BUG_ON()] [Rename variable] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 13:23:03 +00:00
dprintk("RPC: %5u release request %p\n", task->tk_pid, req);
if (likely(!bc_prealloc(req)))
xprt_free_slot(xprt, req);
else
xprt_free_bc_request(req);
}
static void xprt_init(struct rpc_xprt *xprt, struct net *net)
{
atomic_set(&xprt->count, 1);
spin_lock_init(&xprt->transport_lock);
spin_lock_init(&xprt->reserve_lock);
INIT_LIST_HEAD(&xprt->free);
INIT_LIST_HEAD(&xprt->recv);
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
spin_lock_init(&xprt->bc_pa_lock);
INIT_LIST_HEAD(&xprt->bc_pa_list);
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
xprt->last_used = jiffies;
xprt->cwnd = RPC_INITCWND;
xprt->bind_index = 0;
rpc_init_wait_queue(&xprt->binding, "xprt_binding");
rpc_init_wait_queue(&xprt->pending, "xprt_pending");
rpc_init_priority_wait_queue(&xprt->sending, "xprt_sending");
rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
xprt_init_xid(xprt);
xprt->xprt_net = get_net(net);
}
/**
* xprt_create_transport - create an RPC transport
* @args: rpc transport creation arguments
*
*/
struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
{
struct rpc_xprt *xprt;
struct xprt_class *t;
spin_lock(&xprt_list_lock);
list_for_each_entry(t, &xprt_list, list) {
if (t->ident == args->ident) {
spin_unlock(&xprt_list_lock);
goto found;
}
}
spin_unlock(&xprt_list_lock);
printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident);
return ERR_PTR(-EIO);
found:
xprt = t->setup(args);
if (IS_ERR(xprt)) {
dprintk("RPC: xprt_create_transport: failed, %ld\n",
-PTR_ERR(xprt));
goto out;
}
INIT_WORK(&xprt->task_cleanup, xprt_autoclose);
if (xprt_has_timer(xprt))
setup_timer(&xprt->timer, xprt_init_autodisconnect,
(unsigned long)xprt);
else
init_timer(&xprt->timer);
dprintk("RPC: created transport %p with %u slots\n", xprt,
xprt->max_reqs);
out:
return xprt;
}
/**
* xprt_destroy - destroy an RPC transport, killing off all requests.
* @xprt: transport to destroy
*
*/
static void xprt_destroy(struct rpc_xprt *xprt)
{
dprintk("RPC: destroying transport %p\n", xprt);
xprt->shutdown = 1;
del_timer_sync(&xprt->timer);
rpc_destroy_wait_queue(&xprt->binding);
rpc_destroy_wait_queue(&xprt->pending);
rpc_destroy_wait_queue(&xprt->sending);
rpc_destroy_wait_queue(&xprt->backlog);
cancel_work_sync(&xprt->task_cleanup);
/*
* Tear down transport state and free the rpc_xprt
*/
xprt->ops->destroy(xprt);
}
/**
* xprt_put - release a reference to an RPC transport.
* @xprt: pointer to the transport
*
*/
void xprt_put(struct rpc_xprt *xprt)
{
if (atomic_dec_and_test(&xprt->count))
xprt_destroy(xprt);
}
/**
* xprt_get - return a reference to an RPC transport.
* @xprt: pointer to the transport
*
*/
struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
{
if (atomic_inc_not_zero(&xprt->count))
return xprt;
return NULL;
}