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kernel/include/linux/sunrpc/svc.h

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* linux/include/linux/sunrpc/svc.h
*
* RPC server declarations.
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
*/
#ifndef SUNRPC_SVC_H
#define SUNRPC_SVC_H
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/lwq.h>
#include <linux/wait.h>
#include <linux/mm.h>
#include <linux/pagevec.h>
#include <linux/kthread.h>
/*
*
* RPC service thread pool.
*
* Pool of threads and temporary sockets. Generally there is only
* a single one of these per RPC service, but on NUMA machines those
* services that can benefit from it (i.e. nfs but not lockd) will
* have one pool per NUMA node. This optimisation reduces cross-
* node traffic on multi-node NUMA NFS servers.
*/
struct svc_pool {
unsigned int sp_id; /* pool id; also node id on NUMA */
struct lwq sp_xprts; /* pending transports */
unsigned int sp_nrthreads; /* # of threads in pool */
struct list_head sp_all_threads; /* all server threads */
struct llist_head sp_idle_threads; /* idle server threads */
/* statistics on pool operation */
struct percpu_counter sp_messages_arrived;
struct percpu_counter sp_sockets_queued;
struct percpu_counter sp_threads_woken;
unsigned long sp_flags;
} ____cacheline_aligned_in_smp;
/* bits for sp_flags */
enum {
SP_TASK_PENDING, /* still work to do even if no xprt is queued */
SP_NEED_VICTIM, /* One thread needs to agree to exit */
SP_VICTIM_REMAINS, /* One thread needs to actually exit */
};
/*
* RPC service.
*
* An RPC service is a ``daemon,'' possibly multithreaded, which
* receives and processes incoming RPC messages.
* It has one or more transport sockets associated with it, and maintains
* a list of idle threads waiting for input.
*
* We currently do not support more than one RPC program per daemon.
*/
struct svc_serv {
struct svc_program * sv_programs; /* RPC programs */
struct svc_stat * sv_stats; /* RPC statistics */
spinlock_t sv_lock;
unsigned int sv_nprogs; /* Number of sv_programs */
unsigned int sv_nrthreads; /* # of server threads */
unsigned int sv_maxconn; /* max connections allowed or
* '0' causing max to be based
* on number of threads. */
unsigned int sv_max_payload; /* datagram payload size */
unsigned int sv_max_mesg; /* max_payload + 1 page for overheads */
unsigned int sv_xdrsize; /* XDR buffer size */
struct list_head sv_permsocks; /* all permanent sockets */
struct list_head sv_tempsocks; /* all temporary sockets */
int sv_tmpcnt; /* count of temporary sockets */
struct timer_list sv_temptimer; /* timer for aging temporary sockets */
char * sv_name; /* service name */
unsigned int sv_nrpools; /* number of thread pools */
bool sv_is_pooled; /* is this a pooled service? */
struct svc_pool * sv_pools; /* array of thread pools */
int (*sv_threadfn)(void *data);
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
struct lwq sv_cb_list; /* queue for callback requests
* that arrive over the same
* connection */
bool sv_bc_enabled; /* service uses backchannel */
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
};
/* This is used by pool_stats to find and lock an svc */
struct svc_info {
struct svc_serv *serv;
struct mutex *mutex;
};
void svc_destroy(struct svc_serv **svcp);
/*
* Maximum payload size supported by a kernel RPC server.
* This is use to determine the max number of pages nfsd is
* willing to return in a single READ operation.
*
* These happen to all be powers of 2, which is not strictly
* necessary but helps enforce the real limitation, which is
* that they should be multiples of PAGE_SIZE.
*
* For UDP transports, a block plus NFS,RPC, and UDP headers
* has to fit into the IP datagram limit of 64K. The largest
* feasible number for all known page sizes is probably 48K,
* but we choose 32K here. This is the same as the historical
* Linux limit; someone who cares more about NFS/UDP performance
* can test a larger number.
*
* For TCP transports we have more freedom. A size of 1MB is
* chosen to match the client limit. Other OSes are known to
* have larger limits, but those numbers are probably beyond
* the point of diminishing returns.
*/
#define RPCSVC_MAXPAYLOAD (1*1024*1024u)
#define RPCSVC_MAXPAYLOAD_TCP RPCSVC_MAXPAYLOAD
#define RPCSVC_MAXPAYLOAD_UDP (32*1024u)
extern u32 svc_max_payload(const struct svc_rqst *rqstp);
/*
* RPC Requests and replies are stored in one or more pages.
* We maintain an array of pages for each server thread.
* Requests are copied into these pages as they arrive. Remaining
* pages are available to write the reply into.
*
* Pages are sent using ->sendmsg with MSG_SPLICE_PAGES so each server thread
* needs to allocate more to replace those used in sending. To help keep track
* of these pages we have a receive list where all pages initialy live, and a
* send list where pages are moved to when there are to be part of a reply.
*
* We use xdr_buf for holding responses as it fits well with NFS
* read responses (that have a header, and some data pages, and possibly
* a tail) and means we can share some client side routines.
*
* The xdr_buf.head kvec always points to the first page in the rq_*pages
* list. The xdr_buf.pages pointer points to the second page on that
* list. xdr_buf.tail points to the end of the first page.
* This assumes that the non-page part of an rpc reply will fit
* in a page - NFSd ensures this. lockd also has no trouble.
*
* Each request/reply pair can have at most one "payload", plus two pages,
* one for the request, and one for the reply.
* We using ->sendfile to return read data, we might need one extra page
* if the request is not page-aligned. So add another '1'.
*/
#define RPCSVC_MAXPAGES ((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE \
+ 2 + 1)
/*
* The context of a single thread, including the request currently being
* processed.
*/
struct svc_rqst {
struct list_head rq_all; /* all threads list */
struct llist_node rq_idle; /* On the idle list */
struct rcu_head rq_rcu_head; /* for RCU deferred kfree */
struct svc_xprt * rq_xprt; /* transport ptr */
struct sockaddr_storage rq_addr; /* peer address */
size_t rq_addrlen;
struct sockaddr_storage rq_daddr; /* dest addr of request
* - reply from here */
size_t rq_daddrlen;
struct svc_serv * rq_server; /* RPC service definition */
struct svc_pool * rq_pool; /* thread pool */
const struct svc_procedure *rq_procinfo;/* procedure info */
struct auth_ops * rq_authop; /* authentication flavour */
struct svc_cred rq_cred; /* auth info */
void * rq_xprt_ctxt; /* transport specific context ptr */
struct svc_deferred_req*rq_deferred; /* deferred request we are replaying */
struct xdr_buf rq_arg;
struct xdr_stream rq_arg_stream;
struct xdr_stream rq_res_stream;
struct page *rq_scratch_page;
struct xdr_buf rq_res;
struct page *rq_pages[RPCSVC_MAXPAGES + 1];
struct page * *rq_respages; /* points into rq_pages */
struct page * *rq_next_page; /* next reply page to use */
struct page * *rq_page_end; /* one past the last page */
struct folio_batch rq_fbatch;
struct kvec rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */
struct bio_vec rq_bvec[RPCSVC_MAXPAGES];
__be32 rq_xid; /* transmission id */
u32 rq_prog; /* program number */
u32 rq_vers; /* program version */
u32 rq_proc; /* procedure number */
u32 rq_prot; /* IP protocol */
int rq_cachetype; /* catering to nfsd */
unsigned long rq_flags; /* flags field */
ktime_t rq_qtime; /* enqueue time */
void * rq_argp; /* decoded arguments */
void * rq_resp; /* xdr'd results */
__be32 *rq_accept_statp;
void * rq_auth_data; /* flavor-specific data */
__be32 rq_auth_stat; /* authentication status */
int rq_auth_slack; /* extra space xdr code
* should leave in head
* for krb5i, krb5p.
*/
int rq_reserved; /* space on socket outq
* reserved for this request
*/
ktime_t rq_stime; /* start time */
struct cache_req rq_chandle; /* handle passed to caches for
* request delaying
*/
/* Catering to nfsd */
struct auth_domain * rq_client; /* RPC peer info */
struct auth_domain * rq_gssclient; /* "gss/"-style peer info */
struct task_struct *rq_task; /* service thread */
struct net *rq_bc_net; /* pointer to backchannel's
* net namespace
*/
int rq_err; /* Thread sets this to inidicate
* initialisation success.
*/
unsigned long bc_to_initval;
unsigned int bc_to_retries;
void ** rq_lease_breaker; /* The v4 client breaking a lease */
unsigned int rq_status_counter; /* RPC processing counter */
};
/* bits for rq_flags */
enum {
RQ_SECURE, /* secure port */
RQ_LOCAL, /* local request */
RQ_USEDEFERRAL, /* use deferral */
RQ_DROPME, /* drop current reply */
RQ_VICTIM, /* Have agreed to shut down */
RQ_DATA, /* request has data */
};
#define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net)
/*
* Rigorous type checking on sockaddr type conversions
*/
static inline struct sockaddr_in *svc_addr_in(const struct svc_rqst *rqst)
{
return (struct sockaddr_in *) &rqst->rq_addr;
}
static inline struct sockaddr_in6 *svc_addr_in6(const struct svc_rqst *rqst)
{
return (struct sockaddr_in6 *) &rqst->rq_addr;
}
static inline struct sockaddr *svc_addr(const struct svc_rqst *rqst)
{
return (struct sockaddr *) &rqst->rq_addr;
}
static inline struct sockaddr_in *svc_daddr_in(const struct svc_rqst *rqst)
{
return (struct sockaddr_in *) &rqst->rq_daddr;
}
static inline struct sockaddr_in6 *svc_daddr_in6(const struct svc_rqst *rqst)
{
return (struct sockaddr_in6 *) &rqst->rq_daddr;
}
static inline struct sockaddr *svc_daddr(const struct svc_rqst *rqst)
{
return (struct sockaddr *) &rqst->rq_daddr;
}
/**
* svc_thread_should_stop - check if this thread should stop
* @rqstp: the thread that might need to stop
*
* To stop an svc thread, the pool flags SP_NEED_VICTIM and SP_VICTIM_REMAINS
* are set. The first thread which sees SP_NEED_VICTIM clears it, becoming
* the victim using this function. It should then promptly call
* svc_exit_thread() to complete the process, clearing SP_VICTIM_REMAINS
* so the task waiting for a thread to exit can wake and continue.
*
* Return values:
* %true: caller should invoke svc_exit_thread()
* %false: caller should do nothing
*/
static inline bool svc_thread_should_stop(struct svc_rqst *rqstp)
{
if (test_and_clear_bit(SP_NEED_VICTIM, &rqstp->rq_pool->sp_flags))
set_bit(RQ_VICTIM, &rqstp->rq_flags);
return test_bit(RQ_VICTIM, &rqstp->rq_flags);
}
/**
* svc_thread_init_status - report whether thread has initialised successfully
* @rqstp: the thread in question
* @err: errno code
*
* After performing any initialisation that could fail, and before starting
* normal work, each sunrpc svc_thread must call svc_thread_init_status()
* with an appropriate error, or zero.
*
* If zero is passed, the thread is ready and must continue until
* svc_thread_should_stop() returns true. If a non-zero error is passed
* the call will not return - the thread will exit.
*/
static inline void svc_thread_init_status(struct svc_rqst *rqstp, int err)
{
rqstp->rq_err = err;
/* memory barrier ensures assignment to error above is visible before
* waitqueue_active() test below completes.
*/
smp_mb();
wake_up_var(&rqstp->rq_err);
if (err)
kthread_exit(1);
}
struct svc_deferred_req {
u32 prot; /* protocol (UDP or TCP) */
struct svc_xprt *xprt;
struct sockaddr_storage addr; /* where reply must go */
size_t addrlen;
struct sockaddr_storage daddr; /* where reply must come from */
size_t daddrlen;
void *xprt_ctxt;
struct cache_deferred_req handle;
int argslen;
__be32 args[];
};
struct svc_process_info {
union {
int (*dispatch)(struct svc_rqst *rqstp);
struct {
unsigned int lovers;
unsigned int hivers;
} mismatch;
};
};
/*
* RPC program - an array of these can use the same transport endpoint
*/
struct svc_program {
u32 pg_prog; /* program number */
unsigned int pg_lovers; /* lowest version */
unsigned int pg_hivers; /* highest version */
unsigned int pg_nvers; /* number of versions */
const struct svc_version **pg_vers; /* version array */
char * pg_name; /* service name */
char * pg_class; /* class name: services sharing authentication */
enum svc_auth_status (*pg_authenticate)(struct svc_rqst *rqstp);
__be32 (*pg_init_request)(struct svc_rqst *,
const struct svc_program *,
struct svc_process_info *);
int (*pg_rpcbind_set)(struct net *net,
const struct svc_program *,
u32 version, int family,
unsigned short proto,
unsigned short port);
};
/*
* RPC program version
*/
struct svc_version {
u32 vs_vers; /* version number */
u32 vs_nproc; /* number of procedures */
const struct svc_procedure *vs_proc; /* per-procedure info */
unsigned long __percpu *vs_count; /* call counts */
u32 vs_xdrsize; /* xdrsize needed for this version */
/* Don't register with rpcbind */
bool vs_hidden;
/* Don't care if the rpcbind registration fails */
bool vs_rpcb_optnl;
/* Need xprt with congestion control */
bool vs_need_cong_ctrl;
/* Dispatch function */
int (*vs_dispatch)(struct svc_rqst *rqstp);
};
/*
* RPC procedure info
*/
struct svc_procedure {
/* process the request: */
__be32 (*pc_func)(struct svc_rqst *);
/* XDR decode args: */
bool (*pc_decode)(struct svc_rqst *rqstp,
struct xdr_stream *xdr);
/* XDR encode result: */
bool (*pc_encode)(struct svc_rqst *rqstp,
struct xdr_stream *xdr);
/* XDR free result: */
void (*pc_release)(struct svc_rqst *);
unsigned int pc_argsize; /* argument struct size */
unsigned int pc_argzero; /* how much of argument to clear */
unsigned int pc_ressize; /* result struct size */
unsigned int pc_cachetype; /* cache info (NFS) */
unsigned int pc_xdrressize; /* maximum size of XDR reply */
const char * pc_name; /* for display */
};
/*
* Function prototypes.
*/
int sunrpc_set_pool_mode(const char *val);
int sunrpc_get_pool_mode(char *val, size_t size);
void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net);
int svc_bind(struct svc_serv *serv, struct net *net);
struct svc_serv *svc_create(struct svc_program *, unsigned int,
int (*threadfn)(void *data));
bool svc_rqst_replace_page(struct svc_rqst *rqstp,
struct page *page);
void svc_rqst_release_pages(struct svc_rqst *rqstp);
void svc_exit_thread(struct svc_rqst *);
struct svc_serv * svc_create_pooled(struct svc_program *prog,
unsigned int nprog,
struct svc_stat *stats,
unsigned int bufsize,
int (*threadfn)(void *data));
int svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
int svc_pool_stats_open(struct svc_info *si, struct file *file);
void svc_process(struct svc_rqst *rqstp);
void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp);
int svc_register(const struct svc_serv *, struct net *, const int,
const unsigned short, const unsigned short);
void svc_wake_up(struct svc_serv *);
void svc_reserve(struct svc_rqst *rqstp, int space);
void svc_pool_wake_idle_thread(struct svc_pool *pool);
struct svc_pool *svc_pool_for_cpu(struct svc_serv *serv);
char * svc_print_addr(struct svc_rqst *, char *, size_t);
const char * svc_proc_name(const struct svc_rqst *rqstp);
int svc_encode_result_payload(struct svc_rqst *rqstp,
unsigned int offset,
unsigned int length);
unsigned int svc_fill_write_vector(struct svc_rqst *rqstp,
struct xdr_buf *payload);
char *svc_fill_symlink_pathname(struct svc_rqst *rqstp,
struct kvec *first, void *p,
size_t total);
__be32 svc_generic_init_request(struct svc_rqst *rqstp,
const struct svc_program *progp,
struct svc_process_info *procinfo);
int svc_generic_rpcbind_set(struct net *net,
const struct svc_program *progp,
u32 version, int family,
unsigned short proto,
unsigned short port);
#define RPC_MAX_ADDRBUFLEN (63U)
/*
* When we want to reduce the size of the reserved space in the response
* buffer, we need to take into account the size of any checksum data that
* may be at the end of the packet. This is difficult to determine exactly
* for all cases without actually generating the checksum, so we just use a
* static value.
*/
static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space)
{
svc_reserve(rqstp, space + rqstp->rq_auth_slack);
}
/**
* svcxdr_init_decode - Prepare an xdr_stream for Call decoding
* @rqstp: controlling server RPC transaction context
*
*/
static inline void svcxdr_init_decode(struct svc_rqst *rqstp)
{
struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct xdr_buf *buf = &rqstp->rq_arg;
struct kvec *argv = buf->head;
WARN_ON(buf->len != buf->head->iov_len + buf->page_len + buf->tail->iov_len);
buf->len = buf->head->iov_len + buf->page_len + buf->tail->iov_len;
xdr_init_decode(xdr, buf, argv->iov_base, NULL);
xdr_set_scratch_page(xdr, rqstp->rq_scratch_page);
}
/**
* svcxdr_init_encode - Prepare an xdr_stream for svc Reply encoding
* @rqstp: controlling server RPC transaction context
*
*/
static inline void svcxdr_init_encode(struct svc_rqst *rqstp)
{
struct xdr_stream *xdr = &rqstp->rq_res_stream;
struct xdr_buf *buf = &rqstp->rq_res;
struct kvec *resv = buf->head;
xdr_reset_scratch_buffer(xdr);
xdr->buf = buf;
xdr->iov = resv;
xdr->p = resv->iov_base + resv->iov_len;
xdr->end = resv->iov_base + PAGE_SIZE;
buf->len = resv->iov_len;
xdr->page_ptr = buf->pages - 1;
buf->buflen = PAGE_SIZE * (rqstp->rq_page_end - buf->pages);
xdr->rqst = NULL;
}
/**
* svcxdr_encode_opaque_pages - Insert pages into an xdr_stream
* @xdr: xdr_stream to be updated
* @pages: array of pages to insert
* @base: starting offset of first data byte in @pages
* @len: number of data bytes in @pages to insert
*
* After the @pages are added, the tail iovec is instantiated pointing
* to end of the head buffer, and the stream is set up to encode
* subsequent items into the tail.
*/
static inline void svcxdr_encode_opaque_pages(struct svc_rqst *rqstp,
struct xdr_stream *xdr,
struct page **pages,
unsigned int base,
unsigned int len)
{
xdr_write_pages(xdr, pages, base, len);
xdr->page_ptr = rqstp->rq_next_page - 1;
}
/**
* svcxdr_set_auth_slack -
* @rqstp: RPC transaction
* @slack: buffer space to reserve for the transaction's security flavor
*
* Set the request's slack space requirement, and set aside that much
* space in the rqstp's rq_res.head for use when the auth wraps the Reply.
*/
static inline void svcxdr_set_auth_slack(struct svc_rqst *rqstp, int slack)
{
struct xdr_stream *xdr = &rqstp->rq_res_stream;
struct xdr_buf *buf = &rqstp->rq_res;
struct kvec *resv = buf->head;
rqstp->rq_auth_slack = slack;
xdr->end -= XDR_QUADLEN(slack);
buf->buflen -= rqstp->rq_auth_slack;
WARN_ON(xdr->iov != resv);
WARN_ON(xdr->p > xdr->end);
}
/**
* svcxdr_set_accept_stat - Reserve space for the accept_stat field
* @rqstp: RPC transaction context
*
* Return values:
* %true: Success
* %false: No response buffer space was available
*/
static inline bool svcxdr_set_accept_stat(struct svc_rqst *rqstp)
{
struct xdr_stream *xdr = &rqstp->rq_res_stream;
rqstp->rq_accept_statp = xdr_reserve_space(xdr, XDR_UNIT);
if (unlikely(!rqstp->rq_accept_statp))
return false;
*rqstp->rq_accept_statp = rpc_success;
return true;
}
#endif /* SUNRPC_SVC_H */
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