Release 4.11 net/sunrpc/svc.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/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>


#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_ops->svo_function)


#define SVC_POOL_DEFAULT	SVC_POOL_GLOBAL

/*
 * Structure for mapping cpus to pools and vice versa.
 * Setup once during sunrpc initialisation.
 */

struct svc_pool_map svc_pool_map = {
	.mode = SVC_POOL_DEFAULT
};

EXPORT_SYMBOL_GPL(svc_pool_map);

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;
}

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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);
	}
}

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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;
}

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/*
 * 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;
}

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/*
 * 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;
}
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;


/*
 * 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;
}


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/*
 * 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.
 */

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;
}
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EXPORT_SYMBOL_GPL(svc_pool_map_get);

/*
 * 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.
 */

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);
}
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EXPORT_SYMBOL_GPL(svc_pool_map_put);



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;
}
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/*
 * 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;
	}
	}
}

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/*
 * 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];
}

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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;
}
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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);
}
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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)
				return 1;
		}
	}

	return 0;
}

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int svc_bind(struct svc_serv *serv, struct net *net)
{
	if (!svc_uses_rpcbind(serv))
		return 0;
	return svc_rpcb_setup(serv, net);
}
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EXPORT_SYMBOL_GPL(svc_bind);

#if defined(CONFIG_SUNRPC_BACKCHANNEL)

static void

__svc_init_bc(struct svc_serv *serv)
{
	INIT_LIST_HEAD(&serv->sv_cb_list);
	spin_lock_init(&serv->sv_cb_lock);
	init_waitqueue_head(&serv->sv_cb_waitq);
}
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#else

static void

__svc_init_bc(struct svc_serv *serv)
{
}
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#endif

/*
 * Create an RPC service
 */

static struct svc_serv *

__svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
	     struct svc_serv_ops *ops)
{
	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_ops = ops;
	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);

	__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;
		INIT_LIST_HEAD(&pool->sp_sockets);
		INIT_LIST_HEAD(&pool->sp_all_threads);
		spin_lock_init(&pool->sp_lock);
	}

	return serv;
}

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Andreas Gruenbacher
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Trond Myklebust
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Robert P. J. Day
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Jeff Layton
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Stanislav Kinsbursky
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Chuck Lever
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struct svc_serv *

svc_create(struct svc_program *prog, unsigned int bufsize,
	   struct svc_serv_ops *ops)
{
	return __svc_create(prog, bufsize, /*npools*/1, ops);
}
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EXPORT_SYMBOL_GPL(svc_create);


struct svc_serv *

svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
		  struct svc_serv_ops *ops)
{
	struct svc_serv *serv;
	unsigned int npools = svc_pool_map_get();

	serv = __svc_create(prog, bufsize, npools, ops);
	if (!serv)
		goto out_err;
	return serv;
out_err:
	svc_pool_map_put();
	return NULL;
}
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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_ops->svo_shutdown)
		serv->sv_ops->svo_shutdown(serv, net);
}
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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);
}
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25
20.83%
3
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Stanislav Kinsbursky
23
19.17%
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Neil Brown
14
11.67%
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Chuck Lever
1
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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;
}

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Andy Adamson
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10.00%
Eric Dumazet
8
7.34%
1
10.00%
Chuck Lever
4
3.67%
1
10.00%
Kris Katterjohn
2
1.83%
1
10.00%
Total
109
100.00%
10
100.00%

/*
 * 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]);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Neil Brown
42
80.77%
3
60.00%
Linus Torvalds (pre-git)
9
17.31%
1
20.00%
Chuck Lever
1
1.92%
1
20.00%
Total
52
100.00%
5
100.00%


struct svc_rqst *

svc_rqst_alloc(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;

	__set_bit(RQ_BUSY, &rqstp->rq_flags);
	spin_lock_init(&rqstp->rq_lock);
	rqstp->rq_server = serv;
	rqstp->rq_pool = pool;

	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;

	return rqstp;
out_enomem:
	svc_rqst_free(rqstp);
	return NULL;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Jeff Layton
74
46.84%
3
37.50%
Linus Torvalds (pre-git)
61
38.61%
2
25.00%
Eric Dumazet
14
8.86%
1
12.50%
Greg Banks
8
5.06%
1
12.50%
Neil Brown
1
0.63%
1
12.50%
Total
158
100.00%
8
100.00%


EXPORT_SYMBOL_GPL(svc_rqst_alloc);


struct svc_rqst *

svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
{
	struct svc_rqst	*rqstp;

	rqstp = svc_rqst_alloc(serv, pool, node);
	if (!rqstp)
		return ERR_PTR(-ENOMEM);

	serv->sv_nrthreads++;
	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);
	return rqstp;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Jeff Layton
88
97.78%
2
66.67%
Greg Banks
2
2.22%
1
33.33%
Total
90
100.00%
3
100.00%


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];
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Greg Banks
45
90.00%
1
50.00%
Linus Torvalds (pre-git)
5
10.00%
1
50.00%
Total
50
100.00%
2
100.00%

/*
 * 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Greg Banks
176
90.26%
2
50.00%
Jeff Layton
11
5.64%
1
25.00%
Linus Torvalds (pre-git)
8
4.10%
1
25.00%
Total
195
100.00%
4
100.00%

/*
 * 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_ops->svo_module);
		task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
					      node, "%s", serv->sv_name);
		if (IS_ERR(task)) {
			error = PTR_ERR(task);
			module_put(serv->sv_ops->svo_module);
			svc_exit_thread(rqstp);
			break;
		}

		rqstp