linux/net/sunrpc/svc.c
Jeff Layton b1691bc03d sunrpc: convert to lockless lookup of queued server threads
Testing has shown that the pool->sp_lock can be a bottleneck on a busy
server. Every time data is received on a socket, the server must take
that lock in order to dequeue a thread from the sp_threads list.

Address this problem by eliminating the sp_threads list (which contains
threads that are currently idle) and replacing it with a RQ_BUSY flag in
svc_rqst. This allows us to walk the sp_all_threads list under the
rcu_read_lock and find a suitable thread for the xprt by doing a
test_and_set_bit.

Note that we do still have a potential atomicity problem however with
this approach.  We don't want svc_xprt_do_enqueue to set the
rqst->rq_xprt pointer unless a test_and_set_bit of RQ_BUSY returned
zero (which indicates that the thread was idle). But, by the time we
check that, the bit could be flipped by a waking thread.

To address this, we acquire a new per-rqst spinlock (rq_lock) and take
that before doing the test_and_set_bit. If that returns false, then we
can set rq_xprt and drop the spinlock. Then, when the thread wakes up,
it must set the bit under the same spinlock and can trust that if it was
already set then the rq_xprt is also properly set.

With this scheme, the case where we have an idle thread no longer needs
to take the highly contended pool->sp_lock at all, and that removes the
bottleneck.

That still leaves one issue: What of the case where we walk the whole
sp_all_threads list and don't find an idle thread? Because the search is
lockess, it's possible for the queueing to race with a thread that is
going to sleep. To address that, we queue the xprt and then search again.

If we find an idle thread at that point, we can't attach the xprt to it
directly since that might race with a different thread waking up and
finding it.  All we can do is wake the idle thread back up and let it
attempt to find the now-queued xprt.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Chris Worley <chris.worley@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09 11:22:22 -05:00

1406 lines
33 KiB
C

/*
* linux/net/sunrpc/svc.c
*
* High-level RPC service routines
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
*
* Multiple threads pools and NUMAisation
* Copyright (c) 2006 Silicon Graphics, Inc.
* by Greg Banks <gnb@melbourne.sgi.com>
*/
#include <linux/linkage.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/slab.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/bc_xprt.h>
#include <trace/events/sunrpc.h>
#define RPCDBG_FACILITY RPCDBG_SVCDSP
static void svc_unregister(const struct svc_serv *serv, struct net *net);
#define svc_serv_is_pooled(serv) ((serv)->sv_function)
/*
* Mode for mapping cpus to pools.
*/
enum {
SVC_POOL_AUTO = -1, /* choose one of the others */
SVC_POOL_GLOBAL, /* no mapping, just a single global pool
* (legacy & UP mode) */
SVC_POOL_PERCPU, /* one pool per cpu */
SVC_POOL_PERNODE /* one pool per numa node */
};
#define SVC_POOL_DEFAULT SVC_POOL_GLOBAL
/*
* Structure for mapping cpus to pools and vice versa.
* Setup once during sunrpc initialisation.
*/
static struct svc_pool_map {
int count; /* How many svc_servs use us */
int mode; /* Note: int not enum to avoid
* warnings about "enumeration value
* not handled in switch" */
unsigned int npools;
unsigned int *pool_to; /* maps pool id to cpu or node */
unsigned int *to_pool; /* maps cpu or node to pool id */
} svc_pool_map = {
.count = 0,
.mode = SVC_POOL_DEFAULT
};
static DEFINE_MUTEX(svc_pool_map_mutex);/* protects svc_pool_map.count only */
static int
param_set_pool_mode(const char *val, struct kernel_param *kp)
{
int *ip = (int *)kp->arg;
struct svc_pool_map *m = &svc_pool_map;
int err;
mutex_lock(&svc_pool_map_mutex);
err = -EBUSY;
if (m->count)
goto out;
err = 0;
if (!strncmp(val, "auto", 4))
*ip = SVC_POOL_AUTO;
else if (!strncmp(val, "global", 6))
*ip = SVC_POOL_GLOBAL;
else if (!strncmp(val, "percpu", 6))
*ip = SVC_POOL_PERCPU;
else if (!strncmp(val, "pernode", 7))
*ip = SVC_POOL_PERNODE;
else
err = -EINVAL;
out:
mutex_unlock(&svc_pool_map_mutex);
return err;
}
static int
param_get_pool_mode(char *buf, struct kernel_param *kp)
{
int *ip = (int *)kp->arg;
switch (*ip)
{
case SVC_POOL_AUTO:
return strlcpy(buf, "auto", 20);
case SVC_POOL_GLOBAL:
return strlcpy(buf, "global", 20);
case SVC_POOL_PERCPU:
return strlcpy(buf, "percpu", 20);
case SVC_POOL_PERNODE:
return strlcpy(buf, "pernode", 20);
default:
return sprintf(buf, "%d", *ip);
}
}
module_param_call(pool_mode, param_set_pool_mode, param_get_pool_mode,
&svc_pool_map.mode, 0644);
/*
* Detect best pool mapping mode heuristically,
* according to the machine's topology.
*/
static int
svc_pool_map_choose_mode(void)
{
unsigned int node;
if (nr_online_nodes > 1) {
/*
* Actually have multiple NUMA nodes,
* so split pools on NUMA node boundaries
*/
return SVC_POOL_PERNODE;
}
node = first_online_node;
if (nr_cpus_node(node) > 2) {
/*
* Non-trivial SMP, or CONFIG_NUMA on
* non-NUMA hardware, e.g. with a generic
* x86_64 kernel on Xeons. In this case we
* want to divide the pools on cpu boundaries.
*/
return SVC_POOL_PERCPU;
}
/* default: one global pool */
return SVC_POOL_GLOBAL;
}
/*
* Allocate the to_pool[] and pool_to[] arrays.
* Returns 0 on success or an errno.
*/
static int
svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
{
m->to_pool = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
if (!m->to_pool)
goto fail;
m->pool_to = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
if (!m->pool_to)
goto fail_free;
return 0;
fail_free:
kfree(m->to_pool);
m->to_pool = NULL;
fail:
return -ENOMEM;
}
/*
* Initialise the pool map for SVC_POOL_PERCPU mode.
* Returns number of pools or <0 on error.
*/
static int
svc_pool_map_init_percpu(struct svc_pool_map *m)
{
unsigned int maxpools = nr_cpu_ids;
unsigned int pidx = 0;
unsigned int cpu;
int err;
err = svc_pool_map_alloc_arrays(m, maxpools);
if (err)
return err;
for_each_online_cpu(cpu) {
BUG_ON(pidx >= maxpools);
m->to_pool[cpu] = pidx;
m->pool_to[pidx] = cpu;
pidx++;
}
/* cpus brought online later all get mapped to pool0, sorry */
return pidx;
};
/*
* Initialise the pool map for SVC_POOL_PERNODE mode.
* Returns number of pools or <0 on error.
*/
static int
svc_pool_map_init_pernode(struct svc_pool_map *m)
{
unsigned int maxpools = nr_node_ids;
unsigned int pidx = 0;
unsigned int node;
int err;
err = svc_pool_map_alloc_arrays(m, maxpools);
if (err)
return err;
for_each_node_with_cpus(node) {
/* some architectures (e.g. SN2) have cpuless nodes */
BUG_ON(pidx > maxpools);
m->to_pool[node] = pidx;
m->pool_to[pidx] = node;
pidx++;
}
/* nodes brought online later all get mapped to pool0, sorry */
return pidx;
}
/*
* Add a reference to the global map of cpus to pools (and
* vice versa). Initialise the map if we're the first user.
* Returns the number of pools.
*/
static unsigned int
svc_pool_map_get(void)
{
struct svc_pool_map *m = &svc_pool_map;
int npools = -1;
mutex_lock(&svc_pool_map_mutex);
if (m->count++) {
mutex_unlock(&svc_pool_map_mutex);
return m->npools;
}
if (m->mode == SVC_POOL_AUTO)
m->mode = svc_pool_map_choose_mode();
switch (m->mode) {
case SVC_POOL_PERCPU:
npools = svc_pool_map_init_percpu(m);
break;
case SVC_POOL_PERNODE:
npools = svc_pool_map_init_pernode(m);
break;
}
if (npools < 0) {
/* default, or memory allocation failure */
npools = 1;
m->mode = SVC_POOL_GLOBAL;
}
m->npools = npools;
mutex_unlock(&svc_pool_map_mutex);
return m->npools;
}
/*
* Drop a reference to the global map of cpus to pools.
* When the last reference is dropped, the map data is
* freed; this allows the sysadmin to change the pool
* mode using the pool_mode module option without
* rebooting or re-loading sunrpc.ko.
*/
static void
svc_pool_map_put(void)
{
struct svc_pool_map *m = &svc_pool_map;
mutex_lock(&svc_pool_map_mutex);
if (!--m->count) {
kfree(m->to_pool);
m->to_pool = NULL;
kfree(m->pool_to);
m->pool_to = NULL;
m->npools = 0;
}
mutex_unlock(&svc_pool_map_mutex);
}
static int svc_pool_map_get_node(unsigned int pidx)
{
const struct svc_pool_map *m = &svc_pool_map;
if (m->count) {
if (m->mode == SVC_POOL_PERCPU)
return cpu_to_node(m->pool_to[pidx]);
if (m->mode == SVC_POOL_PERNODE)
return m->pool_to[pidx];
}
return NUMA_NO_NODE;
}
/*
* Set the given thread's cpus_allowed mask so that it
* will only run on cpus in the given pool.
*/
static inline void
svc_pool_map_set_cpumask(struct task_struct *task, unsigned int pidx)
{
struct svc_pool_map *m = &svc_pool_map;
unsigned int node = m->pool_to[pidx];
/*
* The caller checks for sv_nrpools > 1, which
* implies that we've been initialized.
*/
WARN_ON_ONCE(m->count == 0);
if (m->count == 0)
return;
switch (m->mode) {
case SVC_POOL_PERCPU:
{
set_cpus_allowed_ptr(task, cpumask_of(node));
break;
}
case SVC_POOL_PERNODE:
{
set_cpus_allowed_ptr(task, cpumask_of_node(node));
break;
}
}
}
/*
* Use the mapping mode to choose a pool for a given CPU.
* Used when enqueueing an incoming RPC. Always returns
* a non-NULL pool pointer.
*/
struct svc_pool *
svc_pool_for_cpu(struct svc_serv *serv, int cpu)
{
struct svc_pool_map *m = &svc_pool_map;
unsigned int pidx = 0;
/*
* An uninitialised map happens in a pure client when
* lockd is brought up, so silently treat it the
* same as SVC_POOL_GLOBAL.
*/
if (svc_serv_is_pooled(serv)) {
switch (m->mode) {
case SVC_POOL_PERCPU:
pidx = m->to_pool[cpu];
break;
case SVC_POOL_PERNODE:
pidx = m->to_pool[cpu_to_node(cpu)];
break;
}
}
return &serv->sv_pools[pidx % serv->sv_nrpools];
}
int svc_rpcb_setup(struct svc_serv *serv, struct net *net)
{
int err;
err = rpcb_create_local(net);
if (err)
return err;
/* Remove any stale portmap registrations */
svc_unregister(serv, net);
return 0;
}
EXPORT_SYMBOL_GPL(svc_rpcb_setup);
void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net)
{
svc_unregister(serv, net);
rpcb_put_local(net);
}
EXPORT_SYMBOL_GPL(svc_rpcb_cleanup);
static int svc_uses_rpcbind(struct svc_serv *serv)
{
struct svc_program *progp;
unsigned int i;
for (progp = serv->sv_program; progp; progp = progp->pg_next) {
for (i = 0; i < progp->pg_nvers; i++) {
if (progp->pg_vers[i] == NULL)
continue;
if (progp->pg_vers[i]->vs_hidden == 0)
return 1;
}
}
return 0;
}
int svc_bind(struct svc_serv *serv, struct net *net)
{
if (!svc_uses_rpcbind(serv))
return 0;
return svc_rpcb_setup(serv, net);
}
EXPORT_SYMBOL_GPL(svc_bind);
/*
* Create an RPC service
*/
static struct svc_serv *
__svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
void (*shutdown)(struct svc_serv *serv, struct net *net))
{
struct svc_serv *serv;
unsigned int vers;
unsigned int xdrsize;
unsigned int i;
if (!(serv = kzalloc(sizeof(*serv), GFP_KERNEL)))
return NULL;
serv->sv_name = prog->pg_name;
serv->sv_program = prog;
serv->sv_nrthreads = 1;
serv->sv_stats = prog->pg_stats;
if (bufsize > RPCSVC_MAXPAYLOAD)
bufsize = RPCSVC_MAXPAYLOAD;
serv->sv_max_payload = bufsize? bufsize : 4096;
serv->sv_max_mesg = roundup(serv->sv_max_payload + PAGE_SIZE, PAGE_SIZE);
serv->sv_shutdown = shutdown;
xdrsize = 0;
while (prog) {
prog->pg_lovers = prog->pg_nvers-1;
for (vers=0; vers<prog->pg_nvers ; vers++)
if (prog->pg_vers[vers]) {
prog->pg_hivers = vers;
if (prog->pg_lovers > vers)
prog->pg_lovers = vers;
if (prog->pg_vers[vers]->vs_xdrsize > xdrsize)
xdrsize = prog->pg_vers[vers]->vs_xdrsize;
}
prog = prog->pg_next;
}
serv->sv_xdrsize = xdrsize;
INIT_LIST_HEAD(&serv->sv_tempsocks);
INIT_LIST_HEAD(&serv->sv_permsocks);
init_timer(&serv->sv_temptimer);
spin_lock_init(&serv->sv_lock);
serv->sv_nrpools = npools;
serv->sv_pools =
kcalloc(serv->sv_nrpools, sizeof(struct svc_pool),
GFP_KERNEL);
if (!serv->sv_pools) {
kfree(serv);
return NULL;
}
for (i = 0; i < serv->sv_nrpools; i++) {
struct svc_pool *pool = &serv->sv_pools[i];
dprintk("svc: initialising pool %u for %s\n",
i, serv->sv_name);
pool->sp_id = i;
INIT_LIST_HEAD(&pool->sp_sockets);
INIT_LIST_HEAD(&pool->sp_all_threads);
spin_lock_init(&pool->sp_lock);
}
return serv;
}
struct svc_serv *
svc_create(struct svc_program *prog, unsigned int bufsize,
void (*shutdown)(struct svc_serv *serv, struct net *net))
{
return __svc_create(prog, bufsize, /*npools*/1, shutdown);
}
EXPORT_SYMBOL_GPL(svc_create);
struct svc_serv *
svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
void (*shutdown)(struct svc_serv *serv, struct net *net),
svc_thread_fn func, struct module *mod)
{
struct svc_serv *serv;
unsigned int npools = svc_pool_map_get();
serv = __svc_create(prog, bufsize, npools, shutdown);
if (!serv)
goto out_err;
serv->sv_function = func;
serv->sv_module = mod;
return serv;
out_err:
svc_pool_map_put();
return NULL;
}
EXPORT_SYMBOL_GPL(svc_create_pooled);
void svc_shutdown_net(struct svc_serv *serv, struct net *net)
{
svc_close_net(serv, net);
if (serv->sv_shutdown)
serv->sv_shutdown(serv, net);
}
EXPORT_SYMBOL_GPL(svc_shutdown_net);
/*
* Destroy an RPC service. Should be called with appropriate locking to
* protect the sv_nrthreads, sv_permsocks and sv_tempsocks.
*/
void
svc_destroy(struct svc_serv *serv)
{
dprintk("svc: svc_destroy(%s, %d)\n",
serv->sv_program->pg_name,
serv->sv_nrthreads);
if (serv->sv_nrthreads) {
if (--(serv->sv_nrthreads) != 0) {
svc_sock_update_bufs(serv);
return;
}
} else
printk("svc_destroy: no threads for serv=%p!\n", serv);
del_timer_sync(&serv->sv_temptimer);
/*
* The last user is gone and thus all sockets have to be destroyed to
* the point. Check this.
*/
BUG_ON(!list_empty(&serv->sv_permsocks));
BUG_ON(!list_empty(&serv->sv_tempsocks));
cache_clean_deferred(serv);
if (svc_serv_is_pooled(serv))
svc_pool_map_put();
kfree(serv->sv_pools);
kfree(serv);
}
EXPORT_SYMBOL_GPL(svc_destroy);
/*
* Allocate an RPC server's buffer space.
* We allocate pages and place them in rq_argpages.
*/
static int
svc_init_buffer(struct svc_rqst *rqstp, unsigned int size, int node)
{
unsigned int pages, arghi;
/* bc_xprt uses fore channel allocated buffers */
if (svc_is_backchannel(rqstp))
return 1;
pages = size / PAGE_SIZE + 1; /* extra page as we hold both request and reply.
* We assume one is at most one page
*/
arghi = 0;
WARN_ON_ONCE(pages > RPCSVC_MAXPAGES);
if (pages > RPCSVC_MAXPAGES)
pages = RPCSVC_MAXPAGES;
while (pages) {
struct page *p = alloc_pages_node(node, GFP_KERNEL, 0);
if (!p)
break;
rqstp->rq_pages[arghi++] = p;
pages--;
}
return pages == 0;
}
/*
* Release an RPC server buffer
*/
static void
svc_release_buffer(struct svc_rqst *rqstp)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(rqstp->rq_pages); i++)
if (rqstp->rq_pages[i])
put_page(rqstp->rq_pages[i]);
}
struct svc_rqst *
svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
{
struct svc_rqst *rqstp;
rqstp = kzalloc_node(sizeof(*rqstp), GFP_KERNEL, node);
if (!rqstp)
goto out_enomem;
serv->sv_nrthreads++;
__set_bit(RQ_BUSY, &rqstp->rq_flags);
spin_lock_init(&rqstp->rq_lock);
rqstp->rq_server = serv;
rqstp->rq_pool = pool;
spin_lock_bh(&pool->sp_lock);
pool->sp_nrthreads++;
list_add_rcu(&rqstp->rq_all, &pool->sp_all_threads);
spin_unlock_bh(&pool->sp_lock);
rqstp->rq_argp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
if (!rqstp->rq_argp)
goto out_thread;
rqstp->rq_resp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
if (!rqstp->rq_resp)
goto out_thread;
if (!svc_init_buffer(rqstp, serv->sv_max_mesg, node))
goto out_thread;
return rqstp;
out_thread:
svc_exit_thread(rqstp);
out_enomem:
return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL_GPL(svc_prepare_thread);
/*
* Choose a pool in which to create a new thread, for svc_set_num_threads
*/
static inline struct svc_pool *
choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
{
if (pool != NULL)
return pool;
return &serv->sv_pools[(*state)++ % serv->sv_nrpools];
}
/*
* Choose a thread to kill, for svc_set_num_threads
*/
static inline struct task_struct *
choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
{
unsigned int i;
struct task_struct *task = NULL;
if (pool != NULL) {
spin_lock_bh(&pool->sp_lock);
} else {
/* choose a pool in round-robin fashion */
for (i = 0; i < serv->sv_nrpools; i++) {
pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
spin_lock_bh(&pool->sp_lock);
if (!list_empty(&pool->sp_all_threads))
goto found_pool;
spin_unlock_bh(&pool->sp_lock);
}
return NULL;
}
found_pool:
if (!list_empty(&pool->sp_all_threads)) {
struct svc_rqst *rqstp;
/*
* Remove from the pool->sp_all_threads list
* so we don't try to kill it again.
*/
rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);
set_bit(RQ_VICTIM, &rqstp->rq_flags);
list_del_rcu(&rqstp->rq_all);
task = rqstp->rq_task;
}
spin_unlock_bh(&pool->sp_lock);
return task;
}
/*
* Create or destroy enough new threads to make the number
* of threads the given number. If `pool' is non-NULL, applies
* only to threads in that pool, otherwise round-robins between
* all pools. Caller must ensure that mutual exclusion between this and
* server startup or shutdown.
*
* Destroying threads relies on the service threads filling in
* rqstp->rq_task, which only the nfs ones do. Assumes the serv
* has been created using svc_create_pooled().
*
* Based on code that used to be in nfsd_svc() but tweaked
* to be pool-aware.
*/
int
svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
struct svc_rqst *rqstp;
struct task_struct *task;
struct svc_pool *chosen_pool;
int error = 0;
unsigned int state = serv->sv_nrthreads-1;
int node;
if (pool == NULL) {
/* The -1 assumes caller has done a svc_get() */
nrservs -= (serv->sv_nrthreads-1);
} else {
spin_lock_bh(&pool->sp_lock);
nrservs -= pool->sp_nrthreads;
spin_unlock_bh(&pool->sp_lock);
}
/* create new threads */
while (nrservs > 0) {
nrservs--;
chosen_pool = choose_pool(serv, pool, &state);
node = svc_pool_map_get_node(chosen_pool->sp_id);
rqstp = svc_prepare_thread(serv, chosen_pool, node);
if (IS_ERR(rqstp)) {
error = PTR_ERR(rqstp);
break;
}
__module_get(serv->sv_module);
task = kthread_create_on_node(serv->sv_function, rqstp,
node, "%s", serv->sv_name);
if (IS_ERR(task)) {
error = PTR_ERR(task);
module_put(serv->sv_module);
svc_exit_thread(rqstp);
break;
}
rqstp->rq_task = task;
if (serv->sv_nrpools > 1)
svc_pool_map_set_cpumask(task, chosen_pool->sp_id);
svc_sock_update_bufs(serv);
wake_up_process(task);
}
/* destroy old threads */
while (nrservs < 0 &&
(task = choose_victim(serv, pool, &state)) != NULL) {
send_sig(SIGINT, task, 1);
nrservs++;
}
return error;
}
EXPORT_SYMBOL_GPL(svc_set_num_threads);
/*
* Called from a server thread as it's exiting. Caller must hold the BKL or
* the "service mutex", whichever is appropriate for the service.
*/
void
svc_exit_thread(struct svc_rqst *rqstp)
{
struct svc_serv *serv = rqstp->rq_server;
struct svc_pool *pool = rqstp->rq_pool;
svc_release_buffer(rqstp);
kfree(rqstp->rq_resp);
kfree(rqstp->rq_argp);
kfree(rqstp->rq_auth_data);
spin_lock_bh(&pool->sp_lock);
pool->sp_nrthreads--;
if (!test_and_set_bit(RQ_VICTIM, &rqstp->rq_flags))
list_del_rcu(&rqstp->rq_all);
spin_unlock_bh(&pool->sp_lock);
kfree_rcu(rqstp, rq_rcu_head);
/* Release the server */
if (serv)
svc_destroy(serv);
}
EXPORT_SYMBOL_GPL(svc_exit_thread);
/*
* Register an "inet" protocol family netid with the local
* rpcbind daemon via an rpcbind v4 SET request.
*
* No netconfig infrastructure is available in the kernel, so
* we map IP_ protocol numbers to netids by hand.
*
* Returns zero on success; a negative errno value is returned
* if any error occurs.
*/
static int __svc_rpcb_register4(struct net *net, const u32 program,
const u32 version,
const unsigned short protocol,
const unsigned short port)
{
const struct sockaddr_in sin = {
.sin_family = AF_INET,
.sin_addr.s_addr = htonl(INADDR_ANY),
.sin_port = htons(port),
};
const char *netid;
int error;
switch (protocol) {
case IPPROTO_UDP:
netid = RPCBIND_NETID_UDP;
break;
case IPPROTO_TCP:
netid = RPCBIND_NETID_TCP;
break;
default:
return -ENOPROTOOPT;
}
error = rpcb_v4_register(net, program, version,
(const struct sockaddr *)&sin, netid);
/*
* User space didn't support rpcbind v4, so retry this
* registration request with the legacy rpcbind v2 protocol.
*/
if (error == -EPROTONOSUPPORT)
error = rpcb_register(net, program, version, protocol, port);
return error;
}
#if IS_ENABLED(CONFIG_IPV6)
/*
* Register an "inet6" protocol family netid with the local
* rpcbind daemon via an rpcbind v4 SET request.
*
* No netconfig infrastructure is available in the kernel, so
* we map IP_ protocol numbers to netids by hand.
*
* Returns zero on success; a negative errno value is returned
* if any error occurs.
*/
static int __svc_rpcb_register6(struct net *net, const u32 program,
const u32 version,
const unsigned short protocol,
const unsigned short port)
{
const struct sockaddr_in6 sin6 = {
.sin6_family = AF_INET6,
.sin6_addr = IN6ADDR_ANY_INIT,
.sin6_port = htons(port),
};
const char *netid;
int error;
switch (protocol) {
case IPPROTO_UDP:
netid = RPCBIND_NETID_UDP6;
break;
case IPPROTO_TCP:
netid = RPCBIND_NETID_TCP6;
break;
default:
return -ENOPROTOOPT;
}
error = rpcb_v4_register(net, program, version,
(const struct sockaddr *)&sin6, netid);
/*
* User space didn't support rpcbind version 4, so we won't
* use a PF_INET6 listener.
*/
if (error == -EPROTONOSUPPORT)
error = -EAFNOSUPPORT;
return error;
}
#endif /* IS_ENABLED(CONFIG_IPV6) */
/*
* Register a kernel RPC service via rpcbind version 4.
*
* Returns zero on success; a negative errno value is returned
* if any error occurs.
*/
static int __svc_register(struct net *net, const char *progname,
const u32 program, const u32 version,
const int family,
const unsigned short protocol,
const unsigned short port)
{
int error = -EAFNOSUPPORT;
switch (family) {
case PF_INET:
error = __svc_rpcb_register4(net, program, version,
protocol, port);
break;
#if IS_ENABLED(CONFIG_IPV6)
case PF_INET6:
error = __svc_rpcb_register6(net, program, version,
protocol, port);
#endif
}
return error;
}
/**
* svc_register - register an RPC service with the local portmapper
* @serv: svc_serv struct for the service to register
* @net: net namespace for the service to register
* @family: protocol family of service's listener socket
* @proto: transport protocol number to advertise
* @port: port to advertise
*
* Service is registered for any address in the passed-in protocol family
*/
int svc_register(const struct svc_serv *serv, struct net *net,
const int family, const unsigned short proto,
const unsigned short port)
{
struct svc_program *progp;
struct svc_version *vers;
unsigned int i;
int error = 0;
WARN_ON_ONCE(proto == 0 && port == 0);
if (proto == 0 && port == 0)
return -EINVAL;
for (progp = serv->sv_program; progp; progp = progp->pg_next) {
for (i = 0; i < progp->pg_nvers; i++) {
vers = progp->pg_vers[i];
if (vers == NULL)
continue;
dprintk("svc: svc_register(%sv%d, %s, %u, %u)%s\n",
progp->pg_name,
i,
proto == IPPROTO_UDP? "udp" : "tcp",
port,
family,
vers->vs_hidden ?
" (but not telling portmap)" : "");
if (vers->vs_hidden)
continue;
error = __svc_register(net, progp->pg_name, progp->pg_prog,
i, family, proto, port);
if (vers->vs_rpcb_optnl) {
error = 0;
continue;
}
if (error < 0) {
printk(KERN_WARNING "svc: failed to register "
"%sv%u RPC service (errno %d).\n",
progp->pg_name, i, -error);
break;
}
}
}
return error;
}
/*
* If user space is running rpcbind, it should take the v4 UNSET
* and clear everything for this [program, version]. If user space
* is running portmap, it will reject the v4 UNSET, but won't have
* any "inet6" entries anyway. So a PMAP_UNSET should be sufficient
* in this case to clear all existing entries for [program, version].
*/
static void __svc_unregister(struct net *net, const u32 program, const u32 version,
const char *progname)
{
int error;
error = rpcb_v4_register(net, program, version, NULL, "");
/*
* User space didn't support rpcbind v4, so retry this
* request with the legacy rpcbind v2 protocol.
*/
if (error == -EPROTONOSUPPORT)
error = rpcb_register(net, program, version, 0, 0);
dprintk("svc: %s(%sv%u), error %d\n",
__func__, progname, version, error);
}
/*
* All netids, bind addresses and ports registered for [program, version]
* are removed from the local rpcbind database (if the service is not
* hidden) to make way for a new instance of the service.
*
* The result of unregistration is reported via dprintk for those who want
* verification of the result, but is otherwise not important.
*/
static void svc_unregister(const struct svc_serv *serv, struct net *net)
{
struct svc_program *progp;
unsigned long flags;
unsigned int i;
clear_thread_flag(TIF_SIGPENDING);
for (progp = serv->sv_program; progp; progp = progp->pg_next) {
for (i = 0; i < progp->pg_nvers; i++) {
if (progp->pg_vers[i] == NULL)
continue;
if (progp->pg_vers[i]->vs_hidden)
continue;
dprintk("svc: attempting to unregister %sv%u\n",
progp->pg_name, i);
__svc_unregister(net, progp->pg_prog, i, progp->pg_name);
}
}
spin_lock_irqsave(&current->sighand->siglock, flags);
recalc_sigpending();
spin_unlock_irqrestore(&current->sighand->siglock, flags);
}
/*
* dprintk the given error with the address of the client that caused it.
*/
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
static __printf(2, 3)
void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...)
{
struct va_format vaf;
va_list args;
char buf[RPC_MAX_ADDRBUFLEN];
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
dprintk("svc: %s: %pV", svc_print_addr(rqstp, buf, sizeof(buf)), &vaf);
va_end(args);
}
#else
static __printf(2,3) void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...) {}
#endif
/*
* Common routine for processing the RPC request.
*/
static int
svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
{
struct svc_program *progp;
struct svc_version *versp = NULL; /* compiler food */
struct svc_procedure *procp = NULL;
struct svc_serv *serv = rqstp->rq_server;
kxdrproc_t xdr;
__be32 *statp;
u32 prog, vers, proc;
__be32 auth_stat, rpc_stat;
int auth_res;
__be32 *reply_statp;
rpc_stat = rpc_success;
if (argv->iov_len < 6*4)
goto err_short_len;
/* Will be turned off only in gss privacy case: */
set_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
/* Will be turned off only when NFSv4 Sessions are used */
set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags);
clear_bit(RQ_DROPME, &rqstp->rq_flags);
/* Setup reply header */
rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp);
svc_putu32(resv, rqstp->rq_xid);
vers = svc_getnl(argv);
/* First words of reply: */
svc_putnl(resv, 1); /* REPLY */
if (vers != 2) /* RPC version number */
goto err_bad_rpc;
/* Save position in case we later decide to reject: */
reply_statp = resv->iov_base + resv->iov_len;
svc_putnl(resv, 0); /* ACCEPT */
rqstp->rq_prog = prog = svc_getnl(argv); /* program number */
rqstp->rq_vers = vers = svc_getnl(argv); /* version number */
rqstp->rq_proc = proc = svc_getnl(argv); /* procedure number */
for (progp = serv->sv_program; progp; progp = progp->pg_next)
if (prog == progp->pg_prog)
break;
/*
* Decode auth data, and add verifier to reply buffer.
* We do this before anything else in order to get a decent
* auth verifier.
*/
auth_res = svc_authenticate(rqstp, &auth_stat);
/* Also give the program a chance to reject this call: */
if (auth_res == SVC_OK && progp) {
auth_stat = rpc_autherr_badcred;
auth_res = progp->pg_authenticate(rqstp);
}
switch (auth_res) {
case SVC_OK:
break;
case SVC_GARBAGE:
goto err_garbage;
case SVC_SYSERR:
rpc_stat = rpc_system_err;
goto err_bad;
case SVC_DENIED:
goto err_bad_auth;
case SVC_CLOSE:
if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
svc_close_xprt(rqstp->rq_xprt);
case SVC_DROP:
goto dropit;
case SVC_COMPLETE:
goto sendit;
}
if (progp == NULL)
goto err_bad_prog;
if (vers >= progp->pg_nvers ||
!(versp = progp->pg_vers[vers]))
goto err_bad_vers;
procp = versp->vs_proc + proc;
if (proc >= versp->vs_nproc || !procp->pc_func)
goto err_bad_proc;
rqstp->rq_procinfo = procp;
/* Syntactic check complete */
serv->sv_stats->rpccnt++;
/* Build the reply header. */
statp = resv->iov_base +resv->iov_len;
svc_putnl(resv, RPC_SUCCESS);
/* Bump per-procedure stats counter */
procp->pc_count++;
/* Initialize storage for argp and resp */
memset(rqstp->rq_argp, 0, procp->pc_argsize);
memset(rqstp->rq_resp, 0, procp->pc_ressize);
/* un-reserve some of the out-queue now that we have a
* better idea of reply size
*/
if (procp->pc_xdrressize)
svc_reserve_auth(rqstp, procp->pc_xdrressize<<2);
/* Call the function that processes the request. */
if (!versp->vs_dispatch) {
/* Decode arguments */
xdr = procp->pc_decode;
if (xdr && !xdr(rqstp, argv->iov_base, rqstp->rq_argp))
goto err_garbage;
*statp = procp->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
/* Encode reply */
if (test_bit(RQ_DROPME, &rqstp->rq_flags)) {
if (procp->pc_release)
procp->pc_release(rqstp, NULL, rqstp->rq_resp);
goto dropit;
}
if (*statp == rpc_success &&
(xdr = procp->pc_encode) &&
!xdr(rqstp, resv->iov_base+resv->iov_len, rqstp->rq_resp)) {
dprintk("svc: failed to encode reply\n");
/* serv->sv_stats->rpcsystemerr++; */
*statp = rpc_system_err;
}
} else {
dprintk("svc: calling dispatcher\n");
if (!versp->vs_dispatch(rqstp, statp)) {
/* Release reply info */
if (procp->pc_release)
procp->pc_release(rqstp, NULL, rqstp->rq_resp);
goto dropit;
}
}
/* Check RPC status result */
if (*statp != rpc_success)
resv->iov_len = ((void*)statp) - resv->iov_base + 4;
/* Release reply info */
if (procp->pc_release)
procp->pc_release(rqstp, NULL, rqstp->rq_resp);
if (procp->pc_encode == NULL)
goto dropit;
sendit:
if (svc_authorise(rqstp))
goto dropit;
return 1; /* Caller can now send it */
dropit:
svc_authorise(rqstp); /* doesn't hurt to call this twice */
dprintk("svc: svc_process dropit\n");
return 0;
err_short_len:
svc_printk(rqstp, "short len %Zd, dropping request\n",
argv->iov_len);
goto dropit; /* drop request */
err_bad_rpc:
serv->sv_stats->rpcbadfmt++;
svc_putnl(resv, 1); /* REJECT */
svc_putnl(resv, 0); /* RPC_MISMATCH */
svc_putnl(resv, 2); /* Only RPCv2 supported */
svc_putnl(resv, 2);
goto sendit;
err_bad_auth:
dprintk("svc: authentication failed (%d)\n", ntohl(auth_stat));
serv->sv_stats->rpcbadauth++;
/* Restore write pointer to location of accept status: */
xdr_ressize_check(rqstp, reply_statp);
svc_putnl(resv, 1); /* REJECT */
svc_putnl(resv, 1); /* AUTH_ERROR */
svc_putnl(resv, ntohl(auth_stat)); /* status */
goto sendit;
err_bad_prog:
dprintk("svc: unknown program %d\n", prog);
serv->sv_stats->rpcbadfmt++;
svc_putnl(resv, RPC_PROG_UNAVAIL);
goto sendit;
err_bad_vers:
svc_printk(rqstp, "unknown version (%d for prog %d, %s)\n",
vers, prog, progp->pg_name);
serv->sv_stats->rpcbadfmt++;
svc_putnl(resv, RPC_PROG_MISMATCH);
svc_putnl(resv, progp->pg_lovers);
svc_putnl(resv, progp->pg_hivers);
goto sendit;
err_bad_proc:
svc_printk(rqstp, "unknown procedure (%d)\n", proc);
serv->sv_stats->rpcbadfmt++;
svc_putnl(resv, RPC_PROC_UNAVAIL);
goto sendit;
err_garbage:
svc_printk(rqstp, "failed to decode args\n");
rpc_stat = rpc_garbage_args;
err_bad:
serv->sv_stats->rpcbadfmt++;
svc_putnl(resv, ntohl(rpc_stat));
goto sendit;
}
EXPORT_SYMBOL_GPL(svc_process);
/*
* Process the RPC request.
*/
int
svc_process(struct svc_rqst *rqstp)
{
struct kvec *argv = &rqstp->rq_arg.head[0];
struct kvec *resv = &rqstp->rq_res.head[0];
struct svc_serv *serv = rqstp->rq_server;
u32 dir;
/*
* Setup response xdr_buf.
* Initially it has just one page
*/
rqstp->rq_next_page = &rqstp->rq_respages[1];
resv->iov_base = page_address(rqstp->rq_respages[0]);
resv->iov_len = 0;
rqstp->rq_res.pages = rqstp->rq_respages + 1;
rqstp->rq_res.len = 0;
rqstp->rq_res.page_base = 0;
rqstp->rq_res.page_len = 0;
rqstp->rq_res.buflen = PAGE_SIZE;
rqstp->rq_res.tail[0].iov_base = NULL;
rqstp->rq_res.tail[0].iov_len = 0;
dir = svc_getnl(argv);
if (dir != 0) {
/* direction != CALL */
svc_printk(rqstp, "bad direction %d, dropping request\n", dir);
serv->sv_stats->rpcbadfmt++;
goto out_drop;
}
/* Returns 1 for send, 0 for drop */
if (likely(svc_process_common(rqstp, argv, resv))) {
int ret = svc_send(rqstp);
trace_svc_process(rqstp, ret);
return ret;
}
out_drop:
trace_svc_process(rqstp, 0);
svc_drop(rqstp);
return 0;
}
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
/*
* Process a backchannel RPC request that arrived over an existing
* outbound connection
*/
int
bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
struct svc_rqst *rqstp)
{
struct kvec *argv = &rqstp->rq_arg.head[0];
struct kvec *resv = &rqstp->rq_res.head[0];
/* Build the svc_rqst used by the common processing routine */
rqstp->rq_xprt = serv->sv_bc_xprt;
rqstp->rq_xid = req->rq_xid;
rqstp->rq_prot = req->rq_xprt->prot;
rqstp->rq_server = serv;
rqstp->rq_addrlen = sizeof(req->rq_xprt->addr);
memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen);
memcpy(&rqstp->rq_arg, &req->rq_rcv_buf, sizeof(rqstp->rq_arg));
memcpy(&rqstp->rq_res, &req->rq_snd_buf, sizeof(rqstp->rq_res));
/* reset result send buffer "put" position */
resv->iov_len = 0;
if (rqstp->rq_prot != IPPROTO_TCP) {
printk(KERN_ERR "No support for Non-TCP transports!\n");
BUG();
}
/*
* Skip the next two words because they've already been
* processed in the trasport
*/
svc_getu32(argv); /* XID */
svc_getnl(argv); /* CALLDIR */
/* Returns 1 for send, 0 for drop */
if (svc_process_common(rqstp, argv, resv)) {
memcpy(&req->rq_snd_buf, &rqstp->rq_res,
sizeof(req->rq_snd_buf));
return bc_send(req);
} else {
/* drop request */
xprt_free_bc_request(req);
return 0;
}
}
EXPORT_SYMBOL_GPL(bc_svc_process);
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
/*
* Return (transport-specific) limit on the rpc payload.
*/
u32 svc_max_payload(const struct svc_rqst *rqstp)
{
u32 max = rqstp->rq_xprt->xpt_class->xcl_max_payload;
if (rqstp->rq_server->sv_max_payload < max)
max = rqstp->rq_server->sv_max_payload;
return max;
}
EXPORT_SYMBOL_GPL(svc_max_payload);