// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/net/sunrpc/svc.c
*
* High-level RPC service routines
*
* Copyright (C) 1995, 1996 Olaf Kirch <[email protected]>
*
* Multiple threads pools and NUMAisation
* Copyright (c) 2006 Silicon Graphics, Inc.
* by Greg Banks <[email protected]>
*/
#include <linux/linkage.h>
#include <linux/sched/signal.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>
#include "fail.h"
#include "sunrpc.h"
#define RPCDBG_FACILITY RPCDBG_SVCDSP
static void svc_unregister(const struct svc_serv *serv, struct net *net);
#define SVC_POOL_DEFAULT SVC_POOL_GLOBAL
/*
* 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 */
};
/*
* Structure for mapping cpus to pools and vice versa.
* Setup once during sunrpc initialisation.
*/
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 */
};
static struct svc_pool_map svc_pool_map = {
.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 svc_pool_map *m)
{
int err, mode;
mutex_lock(&svc_pool_map_mutex);
err = 0;
if (!strncmp(val, "auto", 4))
mode = SVC_POOL_AUTO;
else if (!strncmp(val, "global", 6))
mode = SVC_POOL_GLOBAL;
else if (!strncmp(val, "percpu", 6))
mode = SVC_POOL_PERCPU;
else if (!strncmp(val, "pernode", 7))
mode = SVC_POOL_PERNODE;
else
err = -EINVAL;
if (err)
goto out;
if (m->count == 0)
m->mode = mode;
else if (mode != m->mode)
err = -EBUSY;
out:
mutex_unlock(&svc_pool_map_mutex);
return err;
}
static int
param_set_pool_mode(const char *val, const struct kernel_param *kp)
{
struct svc_pool_map *m = kp->arg;
return __param_set_pool_mode(val, m);
}
int sunrpc_set_pool_mode(const char *val)
{
return __param_set_pool_mode(val, &svc_pool_map);
}
EXPORT_SYMBOL(sunrpc_set_pool_mode);
/**
* sunrpc_get_pool_mode - get the current pool_mode for the host
* @buf: where to write the current pool_mode
* @size: size of @buf
*
* Grab the current pool_mode from the svc_pool_map and write
* the resulting string to @buf. Returns the number of characters
* written to @buf (a'la snprintf()).
*/
int
sunrpc_get_pool_mode(char *buf, size_t size)
{
struct svc_pool_map *m = &svc_pool_map;
switch (m->mode)
{
case SVC_POOL_AUTO:
return snprintf(buf, size, "auto");
case SVC_POOL_GLOBAL:
return snprintf(buf, size, "global");
case SVC_POOL_PERCPU:
return snprintf(buf, size, "percpu");
case SVC_POOL_PERNODE:
return snprintf(buf, size, "pernode");
default:
return snprintf(buf, size, "%d", m->mode);
}
}
EXPORT_SYMBOL(sunrpc_get_pool_mode);
static int
param_get_pool_mode(char *buf, const struct kernel_param *kp)
{
char str[16];
int len;
len = sunrpc_get_pool_mode(str, ARRAY_SIZE(str));
/* Ensure we have room for newline and NUL */
len = min_t(int, len, ARRAY_SIZE(str) - 2);
/* tack on the newline */
str[len] = '\n';
str[len + 1] = '\0';
return sysfs_emit(buf, "%s", str);
}
module_param_call(pool_mode, param_set_pool_mode, param_get_pool_mode,
&svc_pool_map, 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) if pools are in use.
* Initialise the map if we're the first user.
* Returns the number of pools. If this is '1', no reference
* was taken.
*/
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 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.
*/
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;
}
}
}
/**
* svc_pool_for_cpu - Select pool to run a thread on this cpu
* @serv: An RPC service
*
* Use the active CPU and the svc_pool_map's mode setting to
* select the svc thread pool to use. Once initialized, the
* svc_pool_map does not change.
*
* Return value:
* A pointer to an svc_pool
*/
struct svc_pool *svc_pool_for_cpu(struct svc_serv *serv)
{
struct svc_pool_map *m = &svc_pool_map;
int cpu = raw_smp_processor_id();
unsigned int pidx = 0;
if (serv->sv_nrpools <= 1)
return serv->sv_pools;
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];
}
static 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;
}
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)
{
unsigned int p, i;
for (p = 0; p < serv->sv_nprogs; p++) {
struct svc_program *progp = &serv->sv_programs[p];
for (i = 0; i < progp->pg_nvers; i++) {
if (progp->pg_vers[i] == NULL)
continue;
if (!progp->pg_vers[i]->vs_hidden)
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);
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
static void
__svc_init_bc(struct svc_serv *serv)
{
lwq_init(&serv->sv_cb_list);
}
#else
static void
__svc_init_bc(struct svc_serv *serv)
{
}
#endif
/*
* Create an RPC service
*/
static struct svc_serv *
__svc_create(struct svc_program *prog, int nprogs, struct svc_stat *stats,
unsigned int bufsize, int npools, int (*threadfn)(void *data))
{
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_programs = prog;
serv->sv_nprogs = nprogs;
serv->sv_stats = 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_threadfn = threadfn;
xdrsize = 0;
for (i = 0; i < nprogs; i++) {
struct svc_program *progp = &prog[i];
progp->pg_lovers = progp->pg_nvers-1;
for (vers = 0; vers < progp->pg_nvers ; vers++)
if (progp->pg_vers[vers]) {
progp->pg_hivers = vers;
if (progp->pg_lovers > vers)
progp->pg_lovers = vers;
if (progp->pg_vers[vers]->vs_xdrsize > xdrsize)
xdrsize = progp->pg_vers[vers]->vs_xdrsize;
}
}
serv->sv_xdrsize = xdrsize;
INIT_LIST_HEAD(&serv->sv_tempsocks);
INIT_LIST_HEAD(&serv->sv_permsocks);
timer_setup(&serv->sv_temptimer, NULL, 0);
spin_lock_init(&serv->sv_lock);
__svc_init_bc(serv);
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;
lwq_init(&pool->sp_xprts);
INIT_LIST_HEAD(&pool->sp_all_threads);
init_llist_head(&pool->sp_idle_threads);
percpu_counter_init(&pool->sp_messages_arrived, 0, GFP_KERNEL);
percpu_counter_init(&pool->sp_sockets_queued, 0, GFP_KERNEL);
percpu_counter_init(&pool->sp_threads_woken, 0, GFP_KERNEL);
}
return serv;
}
/**
* svc_create - Create an RPC service
* @prog: the RPC program the new service will handle
* @bufsize: maximum message size for @prog
* @threadfn: a function to service RPC requests for @prog
*
* Returns an instantiated struct svc_serv object or NULL.
*/
struct svc_serv *svc_create(struct svc_program *prog, unsigned int bufsize,
int (*threadfn)(void *data))
{
return __svc_create(prog, 1, NULL, bufsize, 1, threadfn);
}
EXPORT_SYMBOL_GPL(svc_create);
/**
* svc_create_pooled - Create an RPC service with pooled threads
* @prog: Array of RPC programs the new service will handle
* @nprogs: Number of programs in the array
* @stats: the stats struct if desired
* @bufsize: maximum message size for @prog
* @threadfn: a function to service RPC requests for @prog
*
* Returns an instantiated struct svc_serv object or NULL.
*/
struct svc_serv *svc_create_pooled(struct svc_program *prog,
unsigned int nprogs,
struct svc_stat *stats,
unsigned int bufsize,
int (*threadfn)(void *data))
{
struct svc_serv *serv;
unsigned int npools = svc_pool_map_get();
serv = __svc_create(prog, nprogs, stats, bufsize, npools, threadfn);
if (!serv)
goto out_err;
serv->sv_is_pooled = true;
return serv;
out_err:
svc_pool_map_put();
return NULL;
}
EXPORT_SYMBOL_GPL(svc_create_pooled);
/*
* Destroy an RPC service. Should be called with appropriate locking to
* protect sv_permsocks and sv_tempsocks.
*/
void
svc_destroy(struct svc_serv **servp)
{
struct svc_serv *serv = *servp;
unsigned int i;
*servp = NULL;
dprintk("svc: svc_destroy(%s)\n", serv->sv_programs->pg_name);
timer_shutdown_sync(&serv->sv_temptimer);
/*
* Remaining transports at this point are not expected.
*/
WARN_ONCE(!list_empty(&serv->sv_permsocks),
"SVC: permsocks remain for %s\n", serv->sv_programs->pg_name);
WARN_ONCE(!list_empty(&serv->sv_tempsocks),
"SVC: tempsocks remain for %s\n", serv->sv_programs->pg_name);
cache_clean_deferred(serv);
if (serv->sv_is_pooled)
svc_pool_map_put();
for (i = 0; i < serv->sv_nrpools; i++) {
struct svc_pool *pool = &serv->sv_pools[i];
percpu_counter_destroy(&pool->sp_messages_arrived);
percpu_counter_destroy(&pool->sp_sockets_queued);
percpu_counter_destroy(&pool->sp_threads_woken);
}
kfree(serv->sv_pools);
kfree(serv);
}
EXPORT_SYMBOL_GPL(svc_destroy);
static bool
svc_init_buffer(struct svc_rqst *rqstp, unsigned int size, int node)
{
unsigned long pages, ret;
/* bc_xprt uses fore channel allocated buffers */
if (svc_is_backchannel(rqstp))
return true;
pages = size / PAGE_SIZE + 1; /* extra page as we hold both request and reply.
* We assume one is at most one page
*/
WARN_ON_ONCE(pages > RPCSVC_MAXPAGES);
if (pages > RPCSVC_MAXPAGES)
pages = RPCSVC_MAXPAGES;
ret = alloc_pages_bulk_array_node(GFP_KERNEL, node, pages,
rqstp->rq_pages);
return ret == pages;
}
/*
* 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]);
}
static void
svc_rqst_free(struct svc_rqst *rqstp)
{
folio_batch_release(&rqstp->rq_fbatch);
svc_release_buffer(rqstp);
if (rqstp->rq_scratch_page)
put_page(rqstp->rq_scratch_page);
kfree(rqstp->rq_resp);
kfree(rqstp->rq_argp);
kfree(rqstp->rq_auth_data);
kfree_rcu(rqstp, rq_rcu_head);
}
static 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)
return rqstp;
folio_batch_init(&rqstp->rq_fbatch);
rqstp->rq_server = serv;
rqstp->rq_pool = pool;
rqstp->rq_scratch_page = alloc_pages_node(node, GFP_KERNEL, 0);
if (!rqstp->rq_scratch_page)
goto out_enomem;
rqstp->rq_argp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
if (!rqstp->rq_argp)
goto out_enomem;
rqstp->rq_resp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
if (!rqstp->rq_resp)
goto out_enomem;
if (!svc_init_buffer(rqstp, serv->sv_max_mesg, node))
goto out_enomem;
rqstp->rq_err = -EAGAIN; /* No error yet */
serv->sv_nrthreads += 1;
pool->sp_nrthreads += 1;
/* Protected by whatever lock the service uses when calling
* svc_set_num_threads()
*/
list_add_rcu(&rqstp->rq_all, &pool->sp_all_threads);
return rqstp;
out_enomem:
svc_rqst_free(rqstp);
return NULL;
}
/**
* svc_pool_wake_idle_thread - Awaken an idle thread in @pool
* @pool: service thread pool
*
* Can be called from soft IRQ or process context. Finding an idle
* service thread and marking it BUSY is atomic with respect to
* other calls to svc_pool_wake_idle_thread().
*
*/
void svc_pool_wake_idle_thread(struct svc_pool *pool)
{
struct svc_rqst *rqstp;
struct llist_node *ln;
rcu_read_lock();
ln = READ_ONCE(pool->sp_idle_threads.first);
if (ln) {
rqstp = llist_entry(ln, struct svc_rqst, rq_idle);
WRITE_ONCE(rqstp->rq_qtime, ktime_get());
if (!task_is_running(rqstp->rq_task)) {
wake_up_process(rqstp->rq_task);
trace_svc_wake_up(rqstp->rq_task->pid);
percpu_counter_inc(&pool->sp_threads_woken);
}
rcu_read_unlock();
return;
}
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(svc_pool_wake_idle_thread);
static struct svc_pool *
svc_pool_next(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
{
return pool ? pool : &serv->sv_pools[(*state)++ % serv->sv_nrpools];
}
static struct svc_pool *
svc_pool_victim(struct svc_serv *serv, struct svc_pool *target_pool,
unsigned int *state)
{
struct svc_pool *pool;
unsigned int i;
pool = target_pool;
if (!pool) {
for (i = 0; i < serv->sv_nrpools; i++) {
pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
if (pool->sp_nrthreads)
break;
}
}
if (pool && pool->sp_nrthreads) {
set_bit(SP_VICTIM_REMAINS, &pool->sp_flags);
set_bit(SP_NEED_VICTIM, &pool->sp_flags);
return pool;
}
return NULL;
}
static int
svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
struct svc_rqst *rqstp;
struct task_struct *task;
struct svc_pool *chosen_pool;
unsigned int state = serv->sv_nrthreads-1;
int node;
int err;
do {
nrservs--;
chosen_pool = svc_pool_next(serv, pool, &state);
node = svc_pool_map_get_node(chosen_pool->sp_id);
rqstp = svc_prepare_thread(serv, chosen_pool, node);
if (!rqstp)
return -ENOMEM;
task = kthread_create_on_node(serv->sv_threadfn, rqstp,
node, "%s", serv->sv_name);
if (IS_ERR(task)) {
svc_exit_thread(rqstp);
return PTR_ERR(task);
}
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);
wait_var_event(&rqstp->rq_err, rqstp->rq_err != -EAGAIN);
err = rqstp->rq_err;
if (err) {
svc_exit_thread(rqstp);
return err;
}
} while (nrservs > 0);
return 0;
}
static int
svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
unsigned int state = serv->sv_nrthreads-1;
struct svc_pool *victim;
do {
victim = svc_pool_victim(serv, pool, &state);
if (!victim)
break;
svc_pool_wake_idle_thread(victim);
wait_on_bit(&victim->sp_flags, SP_VICTIM_REMAINS,
TASK_IDLE);
nrservs++;
} while (nrservs < 0);
return 0;
}
/**
* svc_set_num_threads - adjust number of threads per RPC service
* @serv: RPC service to adjust
* @pool: Specific pool from which to choose threads, or NULL
* @nrservs: New number of threads for @serv (0 or less means kill all threads)
*
* Create or destroy threads to make the number of threads for @serv the
* given number. If @pool is non-NULL, change only threads in that pool;
* otherwise, round-robin between all pools for @serv. @serv's
* sv_nrthreads is adjusted for each thread created or destroyed.
*
* Caller must ensure mutual exclusion between this and server startup or
* shutdown.
*
* Returns zero on success or a negative errno if an error occurred while
* starting a thread.
*/
int
svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
if (!pool)
nrservs -= serv->sv_nrthreads;
else
nrservs -= pool->sp_nrthreads;
if (nrservs > 0)
return svc_start_kthreads(serv, pool, nrservs);
if (nrservs < 0)
return svc_stop_kthreads(serv, pool, nrservs);
return 0;
}
EXPORT_SYMBOL_GPL(svc_set_num_threads);
/**
* svc_rqst_replace_page - Replace one page in rq_pages[]
* @rqstp: svc_rqst with pages to replace
* @page: replacement page
*
* When replacing a page in rq_pages, batch the release of the
* replaced pages to avoid hammering the page allocator.
*
* Return values:
* %true: page replaced
* %false: array bounds checking failed
*/
bool svc_rqst_replace_page(struct svc_rqst *rqstp, struct page *page)
{
struct page **begin = rqstp->rq_pages;
struct page **end = &rqstp->rq_pages[RPCSVC_MAXPAGES];
if (unlikely(rqstp->rq_next_page < begin || rqstp->rq_next_page > end)) {
trace_svc_replace_page_err(rqstp);
return false;
}
if (*rqstp->rq_next_page) {
if (!folio_batch_add(&rqstp->rq_fbatch,
page_folio(*rqstp->rq_next_page)))
__folio_batch_release(&rqstp->rq_fbatch);
}
get_page(page);
*(rqstp->rq_next_page++) = page;
return true;
}
EXPORT_SYMBOL_GPL(svc_rqst_replace_page);
/**
* svc_rqst_release_pages - Release Reply buffer pages
* @rqstp: RPC transaction context
*
* Release response pages that might still be in flight after
* svc_send, and any spliced filesystem-owned pages.
*/
void svc_rqst_release_pages(struct svc_rqst *rqstp)
{
int i, count = rqstp->rq_next_page - rqstp->rq_respages;
if (count) {
release_pages(rqstp->rq_respages, count);
for (i = 0; i < count; i++)
rqstp->rq_respages[i] = NULL;
}
}
/**
* svc_exit_thread - finalise the termination of a sunrpc server thread
* @rqstp: the svc_rqst which represents the thread.
*
* When a thread started with svc_new_thread() exits it must call
* svc_exit_thread() as its last act. This must be done with the
* service mutex held. Normally this is held by a DIFFERENT thread, the
* one that is calling svc_set_num_threads() and which will wait for
* SP_VICTIM_REMAINS to be cleared before dropping the mutex. If the
* thread exits for any reason other than svc_thread_should_stop()
* returning %true (which indicated that svc_set_num_threads() is
* waiting for it to exit), then it must take the service mutex itself,
* which can only safely be done using mutex_try_lock().
*/
void
svc_exit_thread(struct svc_rqst *rqstp)
{
struct svc_serv *serv = rqstp->rq_server;
struct svc_pool *pool = rqstp->rq_pool;
list_del_rcu(&rqstp->rq_all);
pool->sp_nrthreads -= 1;
serv->sv_nrthreads -= 1;
svc_sock_update_bufs(serv);
svc_rqst_free(rqstp);
clear_and_wake_up_bit(SP_VICTIM_REMAINS, &pool->sp_flags);
}
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
}
trace_svc_register(progname, version, family, protocol, port, error);
return error;
}
static
int svc_rpcbind_set_version(struct net *net,
const struct svc_program *progp,
u32 version, int family,
unsigned short proto,
unsigned short port)
{
return __svc_register(net, progp->pg_name, progp->pg_prog,
version, family, proto, port);
}
int svc_generic_rpcbind_set(struct net *net,
const struct svc_program *progp,
u32 version, int family,
unsigned short proto,
unsigned short port)
{
const struct svc_version *vers = progp->pg_vers[version];
int error;
if (vers == NULL)
return 0;
if (vers->vs_hidden) {
trace_svc_noregister(progp->pg_name, version, proto,
port, family, 0);
return 0;
}
/*
* Don't register a UDP port if we need congestion
* control.
*/
if (vers->vs_need_cong_ctrl && proto == IPPROTO_UDP)
return 0;
error = svc_rpcbind_set_version(net, progp, version,
family, proto, port);
return (vers->vs_rpcb_optnl) ? 0 : error;
}
EXPORT_SYMBOL_GPL(svc_generic_rpcbind_set);
/**
* 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)
{
unsigned int p, i;
int error = 0;
WARN_ON_ONCE(proto == 0 && port == 0);
if (proto == 0 && port == 0)
return -EINVAL;
for (p = 0; p < serv->sv_nprogs; p++) {
struct svc_program *progp = &serv->sv_programs[p];
for (i = 0; i < progp->pg_nvers; i++) {
error = progp->pg_rpcbind_set(net, progp, i,
family, proto, port);
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);
trace_svc_unregister(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 sighand_struct *sighand;
unsigned long flags;
unsigned int p, i;
clear_thread_flag(TIF_SIGPENDING);
for (p = 0; p < serv->sv_nprogs; p++) {
struct svc_program *progp = &serv->sv_programs[p];
for (i = 0; i < progp->pg_nvers; i++) {
if (progp->pg_vers[i] == NULL)
continue;
if (progp->pg_vers[i]->vs_hidden)
continue;
__svc_unregister(net, progp->pg_prog, i, progp->pg_name);
}
}
rcu_read_lock();
sighand = rcu_dereference(current->sighand);
spin_lock_irqsave(&sighand->siglock, flags);
recalc_sigpending();
spin_unlock_irqrestore(&sighand->siglock, flags);
rcu_read_unlock();
}
/*
* 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
__be32
svc_generic_init_request(struct svc_rqst *rqstp,
const struct svc_program *progp,
struct svc_process_info *ret)
{
const struct svc_version *versp = NULL; /* compiler food */
const struct svc_procedure *procp = NULL;
if (rqstp->rq_vers >= progp->pg_nvers )
goto err_bad_vers;
versp = progp->pg_vers[rqstp->rq_vers];
if (!versp)
goto err_bad_vers;
/*
* Some protocol versions (namely NFSv4) require some form of
* congestion control. (See RFC 7530 section 3.1 paragraph 2)
* In other words, UDP is not allowed. We mark those when setting
* up the svc_xprt, and verify that here.
*
* The spec is not very clear about what error should be returned
* when someone tries to access a server that is listening on UDP
* for lower versions. RPC_PROG_MISMATCH seems to be the closest
* fit.
*/
if (versp->vs_need_cong_ctrl && rqstp->rq_xprt &&
!test_bit(XPT_CONG_CTRL, &rqstp->rq_xprt->xpt_flags))
goto err_bad_vers;
if (rqstp->rq_proc >= versp->vs_nproc)
goto err_bad_proc;
rqstp->rq_procinfo = procp = &versp->vs_proc[rqstp->rq_proc];
/* Initialize storage for argp and resp */
memset(rqstp->rq_argp, 0, procp->pc_argzero);
memset(rqstp->rq_resp, 0, procp->pc_ressize);
/* Bump per-procedure stats counter */
this_cpu_inc(versp->vs_count[rqstp->rq_proc]);
ret->dispatch = versp->vs_dispatch;
return rpc_success;
err_bad_vers:
ret->mismatch.lovers = progp->pg_lovers;
ret->mismatch.hivers = progp->pg_hivers;
return rpc_prog_mismatch;
err_bad_proc:
return rpc_proc_unavail;
}
EXPORT_SYMBOL_GPL(svc_generic_init_request);
/*
* Common routine for processing the RPC request.
*/
static int
svc_process_common(struct svc_rqst *rqstp)
{
struct xdr_stream *xdr = &rqstp->rq_res_stream;
struct svc_program *progp;
const struct svc_procedure *procp = NULL;
struct svc_serv *serv = rqstp->rq_server;
struct svc_process_info process;
enum svc_auth_status auth_res;
unsigned int aoffset;
int pr, rc;
__be32 *p;
/* Will be turned off only when NFSv4 Sessions are used */
set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags);
clear_bit(RQ_DROPME, &rqstp->rq_flags);
/* Construct the first words of the reply: */
svcxdr_init_encode(rqstp);
xdr_stream_encode_be32(xdr, rqstp->rq_xid);
xdr_stream_encode_be32(xdr, rpc_reply);
p = xdr_inline_decode(&rqstp->rq_arg_stream, XDR_UNIT * 4);
if (unlikely(!p))
goto err_short_len;
if (*p++ != cpu_to_be32(RPC_VERSION))
goto err_bad_rpc;
xdr_stream_encode_be32(xdr, rpc_msg_accepted);
rqstp->rq_prog = be32_to_cpup(p++);
rqstp->rq_vers = be32_to_cpup(p++);
rqstp->rq_proc = be32_to_cpup(p);
for (pr = 0; pr < serv->sv_nprogs; pr++) {
progp = &serv->sv_programs[pr];
if (rqstp->rq_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);
/* Also give the program a chance to reject this call: */
if (auth_res == SVC_OK && progp)
auth_res = progp->pg_authenticate(rqstp);
trace_svc_authenticate(rqstp, auth_res);
switch (auth_res) {
case SVC_OK:
break;
case SVC_GARBAGE:
goto err_garbage_args;
case SVC_SYSERR:
goto err_system_err;
case SVC_DENIED:
goto err_bad_auth;
case SVC_CLOSE:
goto close;
case SVC_DROP:
goto dropit;
case SVC_COMPLETE:
goto sendit;
default:
pr_warn_once("Unexpected svc_auth_status (%d)\n", auth_res);
goto err_system_err;
}
if (progp == NULL)
goto err_bad_prog;
switch (progp->pg_init_request(rqstp, progp, &process)) {
case rpc_success:
break;
case rpc_prog_unavail:
goto err_bad_prog;
case rpc_prog_mismatch:
goto err_bad_vers;
case rpc_proc_unavail:
goto err_bad_proc;
}
procp = rqstp->rq_procinfo;
/* Should this check go into the dispatcher? */
if (!procp || !procp->pc_func)
goto err_bad_proc;
/* Syntactic check complete */
if (serv->sv_stats)
serv->sv_stats->rpccnt++;
trace_svc_process(rqstp, progp->pg_name);
aoffset = xdr_stream_pos(xdr);
/* 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. */
rc = process.dispatch(rqstp);
if (procp->pc_release)
procp->pc_release(rqstp);
xdr_finish_decode(xdr);
if (!rc)
goto dropit;
if (rqstp->rq_auth_stat != rpc_auth_ok)
goto err_bad_auth;
if (*rqstp->rq_accept_statp != rpc_success)
xdr_truncate_encode(xdr, aoffset);
if (procp->pc_encode == NULL)
goto dropit;
sendit:
if (svc_authorise(rqstp))
goto close_xprt;
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;
close:
svc_authorise(rqstp);
close_xprt:
if (rqstp->rq_xprt && test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
svc_xprt_close(rqstp->rq_xprt);
dprintk("svc: svc_process close\n");
return 0;
err_short_len:
svc_printk(rqstp, "short len %u, dropping request\n",
rqstp->rq_arg.len);
goto close_xprt;
err_bad_rpc:
if (serv->sv_stats)
serv->sv_stats->rpcbadfmt++;
xdr_stream_encode_u32(xdr, RPC_MSG_DENIED);
xdr_stream_encode_u32(xdr, RPC_MISMATCH);
/* Only RPCv2 supported */
xdr_stream_encode_u32(xdr, RPC_VERSION);
xdr_stream_encode_u32(xdr, RPC_VERSION);
return 1; /* don't wrap */
err_bad_auth:
dprintk("svc: authentication failed (%d)\n",
be32_to_cpu(rqstp->rq_auth_stat));
if (serv->sv_stats)
serv->sv_stats->rpcbadauth++;
/* Restore write pointer to location of reply status: */
xdr_truncate_encode(xdr, XDR_UNIT * 2);
xdr_stream_encode_u32(xdr, RPC_MSG_DENIED);
xdr_stream_encode_u32(xdr, RPC_AUTH_ERROR);
xdr_stream_encode_be32(xdr, rqstp->rq_auth_stat);
goto sendit;
err_bad_prog:
dprintk("svc: unknown program %d\n", rqstp->rq_prog);
if (serv->sv_stats)
serv->sv_stats->rpcbadfmt++;
*rqstp->rq_accept_statp = rpc_prog_unavail;
goto sendit;
err_bad_vers:
svc_printk(rqstp, "unknown version (%d for prog %d, %s)\n",
rqstp->rq_vers, rqstp->rq_prog, progp->pg_name);
if (serv->sv_stats)
serv->sv_stats->rpcbadfmt++;
*rqstp->rq_accept_statp = rpc_prog_mismatch;
/*
* svc_authenticate() has already added the verifier and
* advanced the stream just past rq_accept_statp.
*/
xdr_stream_encode_u32(xdr, process.mismatch.lovers);
xdr_stream_encode_u32(xdr, process.mismatch.hivers);
goto sendit;
err_bad_proc:
svc_printk(rqstp, "unknown procedure (%d)\n", rqstp->rq_proc);
if (serv->sv_stats)
serv->sv_stats->rpcbadfmt++;
*rqstp->rq_accept_statp = rpc_proc_unavail;
goto sendit;
err_garbage_args:
svc_printk(rqstp, "failed to decode RPC header\n");
if (serv->sv_stats)
serv->sv_stats->rpcbadfmt++;
*rqstp->rq_accept_statp = rpc_garbage_args;
goto sendit;
err_system_err:
if (serv->sv_stats)
serv->sv_stats->rpcbadfmt++;
*rqstp->rq_accept_statp = rpc_system_err;
goto sendit;
}
/*
* Drop request
*/
static void svc_drop(struct svc_rqst *rqstp)
{
trace_svc_drop(rqstp);
}
/**
* svc_process - Execute one RPC transaction
* @rqstp: RPC transaction context
*
*/
void svc_process(struct svc_rqst *rqstp)
{
struct kvec *resv = &rqstp->rq_res.head[0];
__be32 *p;
#if IS_ENABLED(CONFIG_FAIL_SUNRPC)
if (!fail_sunrpc.ignore_server_disconnect &&
should_fail(&fail_sunrpc.attr, 1))
svc_xprt_deferred_close(rqstp->rq_xprt);
#endif
/*
* 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_next_page;
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;
svcxdr_init_decode(rqstp);
p = xdr_inline_decode(&rqstp->rq_arg_stream, XDR_UNIT * 2);
if (unlikely(!p))
goto out_drop;
rqstp->rq_xid = *p++;
if (unlikely(*p != rpc_call))
goto out_baddir;
if (!svc_process_common(rqstp))
goto out_drop;
svc_send(rqstp);
return;
out_baddir:
svc_printk(rqstp, "bad direction 0x%08x, dropping request\n",
be32_to_cpu(*p));
if (rqstp->rq_server->sv_stats)
rqstp->rq_server->sv_stats->rpcbadfmt++;
out_drop:
svc_drop(rqstp);
}
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
/**
* svc_process_bc - process a reverse-direction RPC request
* @req: RPC request to be used for client-side processing
* @rqstp: server-side execution context
*
*/
void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp)
{
struct rpc_timeout timeout = {
.to_increment = 0,
};
struct rpc_task *task;
int proc_error;
/* Build the svc_rqst used by the common processing routine */
rqstp->rq_xid = req->rq_xid;
rqstp->rq_prot = req->rq_xprt->prot;
rqstp->rq_bc_net = req->rq_xprt->xprt_net;
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));
/* Adjust the argument buffer length */
rqstp->rq_arg.len = req->rq_private_buf.len;
if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len) {
rqstp->rq_arg.head[0].iov_len = rqstp->rq_arg.len;
rqstp->rq_arg.page_len = 0;
} else if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len +
rqstp->rq_arg.page_len)
rqstp->rq_arg.page_len = rqstp->rq_arg.len -
rqstp->rq_arg.head[0].iov_len;
else
rqstp->rq_arg.len = rqstp->rq_arg.head[0].iov_len +
rqstp->rq_arg.page_len;
/* Reset the response buffer */
rqstp->rq_res.head[0].iov_len = 0;
/*
* Skip the XID and calldir fields because they've already
* been processed by the caller.
*/
svcxdr_init_decode(rqstp);
if (!xdr_inline_decode(&rqstp->rq_arg_stream, XDR_UNIT * 2))
return;
/* Parse and execute the bc call */
proc_error = svc_process_common(rqstp);
atomic_dec(&req->rq_xprt->bc_slot_count);
if (!proc_error) {
/* Processing error: drop the request */
xprt_free_bc_request(req);
return;
}
/* Finally, send the reply synchronously */
if (rqstp->bc_to_initval > 0) {
timeout.to_initval = rqstp->bc_to_initval;
timeout.to_retries = rqstp->bc_to_retries;
} else {
timeout.to_initval = req->rq_xprt->timeout->to_initval;
timeout.to_retries = req->rq_xprt->timeout->to_retries;
}
timeout.to_maxval = timeout.to_initval;
memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
task = rpc_run_bc_task(req, &timeout);
if (IS_ERR(task))
return;
WARN_ON_ONCE(atomic_read(&task->tk_count) != 1);
rpc_put_task(task);
}
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
/**
* svc_max_payload - Return transport-specific limit on the RPC payload
* @rqstp: RPC transaction context
*
* Returns the maximum number of payload bytes the current transport
* allows.
*/
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);
/**
* svc_proc_name - Return RPC procedure name in string form
* @rqstp: svc_rqst to operate on
*
* Return value:
* Pointer to a NUL-terminated string
*/
const char *svc_proc_name(const struct svc_rqst *rqstp)
{
if (rqstp && rqstp->rq_procinfo)
return rqstp->rq_procinfo->pc_name;
return "unknown";
}
/**
* svc_encode_result_payload - mark a range of bytes as a result payload
* @rqstp: svc_rqst to operate on
* @offset: payload's byte offset in rqstp->rq_res
* @length: size of payload, in bytes
*
* Returns zero on success, or a negative errno if a permanent
* error occurred.
*/
int svc_encode_result_payload(struct svc_rqst *rqstp, unsigned int offset,
unsigned int length)
{
return rqstp->rq_xprt->xpt_ops->xpo_result_payload(rqstp, offset,
length);
}
EXPORT_SYMBOL_GPL(svc_encode_result_payload);
/**
* svc_fill_write_vector - Construct data argument for VFS write call
* @rqstp: svc_rqst to operate on
* @payload: xdr_buf containing only the write data payload
*
* Fills in rqstp::rq_vec, and returns the number of elements.
*/
unsigned int svc_fill_write_vector(struct svc_rqst *rqstp,
struct xdr_buf *payload)
{
struct page **pages = payload->pages;
struct kvec *first = payload->head;
struct kvec *vec = rqstp->rq_vec;
size_t total = payload->len;
unsigned int i;
/* Some types of transport can present the write payload
* entirely in rq_arg.pages. In this case, @first is empty.
*/
i = 0;
if (first->iov_len) {
vec[i].iov_base = first->iov_base;
vec[i].iov_len = min_t(size_t, total, first->iov_len);
total -= vec[i].iov_len;
++i;
}
while (total) {
vec[i].iov_base = page_address(*pages);
vec[i].iov_len = min_t(size_t, total, PAGE_SIZE);
total -= vec[i].iov_len;
++i;
++pages;
}
WARN_ON_ONCE(i > ARRAY_SIZE(rqstp->rq_vec));
return i;
}
EXPORT_SYMBOL_GPL(svc_fill_write_vector);
/**
* svc_fill_symlink_pathname - Construct pathname argument for VFS symlink call
* @rqstp: svc_rqst to operate on
* @first: buffer containing first section of pathname
* @p: buffer containing remaining section of pathname
* @total: total length of the pathname argument
*
* The VFS symlink API demands a NUL-terminated pathname in mapped memory.
* Returns pointer to a NUL-terminated string, or an ERR_PTR. Caller must free
* the returned string.
*/
char *svc_fill_symlink_pathname(struct svc_rqst *rqstp, struct kvec *first,
void *p, size_t total)
{
size_t len, remaining;
char *result, *dst;
result = kmalloc(total + 1, GFP_KERNEL);
if (!result)
return ERR_PTR(-ESERVERFAULT);
dst = result;
remaining = total;
len = min_t(size_t, total, first->iov_len);
if (len) {
memcpy(dst, first->iov_base, len);
dst += len;
remaining -= len;
}
if (remaining) {
len = min_t(size_t, remaining, PAGE_SIZE);
memcpy(dst, p, len);
dst += len;
}
*dst = '\0';
/* Sanity check: Linux doesn't allow the pathname argument to
* contain a NUL byte.
*/
if (strlen(result) != total) {
kfree(result);
return ERR_PTR(-EINVAL);
}
return result;
}
EXPORT_SYMBOL_GPL(svc_fill_symlink_pathname);
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