svc_xprt.c 33 KB

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  1. /*
  2. * linux/net/sunrpc/svc_xprt.c
  3. *
  4. * Author: Tom Tucker <tom@opengridcomputing.com>
  5. */
  6. #include <linux/sched.h>
  7. #include <linux/smp_lock.h>
  8. #include <linux/errno.h>
  9. #include <linux/freezer.h>
  10. #include <linux/kthread.h>
  11. #include <linux/slab.h>
  12. #include <net/sock.h>
  13. #include <linux/sunrpc/stats.h>
  14. #include <linux/sunrpc/svc_xprt.h>
  15. #include <linux/sunrpc/svcsock.h>
  16. #define RPCDBG_FACILITY RPCDBG_SVCXPRT
  17. static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
  18. static int svc_deferred_recv(struct svc_rqst *rqstp);
  19. static struct cache_deferred_req *svc_defer(struct cache_req *req);
  20. static void svc_age_temp_xprts(unsigned long closure);
  21. /* apparently the "standard" is that clients close
  22. * idle connections after 5 minutes, servers after
  23. * 6 minutes
  24. * http://www.connectathon.org/talks96/nfstcp.pdf
  25. */
  26. static int svc_conn_age_period = 6*60;
  27. /* List of registered transport classes */
  28. static DEFINE_SPINLOCK(svc_xprt_class_lock);
  29. static LIST_HEAD(svc_xprt_class_list);
  30. /* SMP locking strategy:
  31. *
  32. * svc_pool->sp_lock protects most of the fields of that pool.
  33. * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
  34. * when both need to be taken (rare), svc_serv->sv_lock is first.
  35. * BKL protects svc_serv->sv_nrthread.
  36. * svc_sock->sk_lock protects the svc_sock->sk_deferred list
  37. * and the ->sk_info_authunix cache.
  38. *
  39. * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
  40. * enqueued multiply. During normal transport processing this bit
  41. * is set by svc_xprt_enqueue and cleared by svc_xprt_received.
  42. * Providers should not manipulate this bit directly.
  43. *
  44. * Some flags can be set to certain values at any time
  45. * providing that certain rules are followed:
  46. *
  47. * XPT_CONN, XPT_DATA:
  48. * - Can be set or cleared at any time.
  49. * - After a set, svc_xprt_enqueue must be called to enqueue
  50. * the transport for processing.
  51. * - After a clear, the transport must be read/accepted.
  52. * If this succeeds, it must be set again.
  53. * XPT_CLOSE:
  54. * - Can set at any time. It is never cleared.
  55. * XPT_DEAD:
  56. * - Can only be set while XPT_BUSY is held which ensures
  57. * that no other thread will be using the transport or will
  58. * try to set XPT_DEAD.
  59. */
  60. int svc_reg_xprt_class(struct svc_xprt_class *xcl)
  61. {
  62. struct svc_xprt_class *cl;
  63. int res = -EEXIST;
  64. dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
  65. INIT_LIST_HEAD(&xcl->xcl_list);
  66. spin_lock(&svc_xprt_class_lock);
  67. /* Make sure there isn't already a class with the same name */
  68. list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
  69. if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
  70. goto out;
  71. }
  72. list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
  73. res = 0;
  74. out:
  75. spin_unlock(&svc_xprt_class_lock);
  76. return res;
  77. }
  78. EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
  79. void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
  80. {
  81. dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
  82. spin_lock(&svc_xprt_class_lock);
  83. list_del_init(&xcl->xcl_list);
  84. spin_unlock(&svc_xprt_class_lock);
  85. }
  86. EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
  87. /*
  88. * Format the transport list for printing
  89. */
  90. int svc_print_xprts(char *buf, int maxlen)
  91. {
  92. struct svc_xprt_class *xcl;
  93. char tmpstr[80];
  94. int len = 0;
  95. buf[0] = '\0';
  96. spin_lock(&svc_xprt_class_lock);
  97. list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
  98. int slen;
  99. sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
  100. slen = strlen(tmpstr);
  101. if (len + slen > maxlen)
  102. break;
  103. len += slen;
  104. strcat(buf, tmpstr);
  105. }
  106. spin_unlock(&svc_xprt_class_lock);
  107. return len;
  108. }
  109. static void svc_xprt_free(struct kref *kref)
  110. {
  111. struct svc_xprt *xprt =
  112. container_of(kref, struct svc_xprt, xpt_ref);
  113. struct module *owner = xprt->xpt_class->xcl_owner;
  114. if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
  115. svcauth_unix_info_release(xprt);
  116. put_net(xprt->xpt_net);
  117. xprt->xpt_ops->xpo_free(xprt);
  118. module_put(owner);
  119. }
  120. void svc_xprt_put(struct svc_xprt *xprt)
  121. {
  122. kref_put(&xprt->xpt_ref, svc_xprt_free);
  123. }
  124. EXPORT_SYMBOL_GPL(svc_xprt_put);
  125. /*
  126. * Called by transport drivers to initialize the transport independent
  127. * portion of the transport instance.
  128. */
  129. void svc_xprt_init(struct svc_xprt_class *xcl, struct svc_xprt *xprt,
  130. struct svc_serv *serv)
  131. {
  132. memset(xprt, 0, sizeof(*xprt));
  133. xprt->xpt_class = xcl;
  134. xprt->xpt_ops = xcl->xcl_ops;
  135. kref_init(&xprt->xpt_ref);
  136. xprt->xpt_server = serv;
  137. INIT_LIST_HEAD(&xprt->xpt_list);
  138. INIT_LIST_HEAD(&xprt->xpt_ready);
  139. INIT_LIST_HEAD(&xprt->xpt_deferred);
  140. INIT_LIST_HEAD(&xprt->xpt_users);
  141. mutex_init(&xprt->xpt_mutex);
  142. spin_lock_init(&xprt->xpt_lock);
  143. set_bit(XPT_BUSY, &xprt->xpt_flags);
  144. rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
  145. xprt->xpt_net = get_net(&init_net);
  146. }
  147. EXPORT_SYMBOL_GPL(svc_xprt_init);
  148. static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
  149. struct svc_serv *serv,
  150. struct net *net,
  151. const int family,
  152. const unsigned short port,
  153. int flags)
  154. {
  155. struct sockaddr_in sin = {
  156. .sin_family = AF_INET,
  157. .sin_addr.s_addr = htonl(INADDR_ANY),
  158. .sin_port = htons(port),
  159. };
  160. #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
  161. struct sockaddr_in6 sin6 = {
  162. .sin6_family = AF_INET6,
  163. .sin6_addr = IN6ADDR_ANY_INIT,
  164. .sin6_port = htons(port),
  165. };
  166. #endif /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
  167. struct sockaddr *sap;
  168. size_t len;
  169. switch (family) {
  170. case PF_INET:
  171. sap = (struct sockaddr *)&sin;
  172. len = sizeof(sin);
  173. break;
  174. #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
  175. case PF_INET6:
  176. sap = (struct sockaddr *)&sin6;
  177. len = sizeof(sin6);
  178. break;
  179. #endif /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
  180. default:
  181. return ERR_PTR(-EAFNOSUPPORT);
  182. }
  183. return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
  184. }
  185. int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
  186. struct net *net, const int family,
  187. const unsigned short port, int flags)
  188. {
  189. struct svc_xprt_class *xcl;
  190. dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
  191. spin_lock(&svc_xprt_class_lock);
  192. list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
  193. struct svc_xprt *newxprt;
  194. if (strcmp(xprt_name, xcl->xcl_name))
  195. continue;
  196. if (!try_module_get(xcl->xcl_owner))
  197. goto err;
  198. spin_unlock(&svc_xprt_class_lock);
  199. newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
  200. if (IS_ERR(newxprt)) {
  201. module_put(xcl->xcl_owner);
  202. return PTR_ERR(newxprt);
  203. }
  204. clear_bit(XPT_TEMP, &newxprt->xpt_flags);
  205. spin_lock_bh(&serv->sv_lock);
  206. list_add(&newxprt->xpt_list, &serv->sv_permsocks);
  207. spin_unlock_bh(&serv->sv_lock);
  208. clear_bit(XPT_BUSY, &newxprt->xpt_flags);
  209. return svc_xprt_local_port(newxprt);
  210. }
  211. err:
  212. spin_unlock(&svc_xprt_class_lock);
  213. dprintk("svc: transport %s not found\n", xprt_name);
  214. /* This errno is exposed to user space. Provide a reasonable
  215. * perror msg for a bad transport. */
  216. return -EPROTONOSUPPORT;
  217. }
  218. EXPORT_SYMBOL_GPL(svc_create_xprt);
  219. /*
  220. * Copy the local and remote xprt addresses to the rqstp structure
  221. */
  222. void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
  223. {
  224. struct sockaddr *sin;
  225. memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
  226. rqstp->rq_addrlen = xprt->xpt_remotelen;
  227. /*
  228. * Destination address in request is needed for binding the
  229. * source address in RPC replies/callbacks later.
  230. */
  231. sin = (struct sockaddr *)&xprt->xpt_local;
  232. switch (sin->sa_family) {
  233. case AF_INET:
  234. rqstp->rq_daddr.addr = ((struct sockaddr_in *)sin)->sin_addr;
  235. break;
  236. case AF_INET6:
  237. rqstp->rq_daddr.addr6 = ((struct sockaddr_in6 *)sin)->sin6_addr;
  238. break;
  239. }
  240. }
  241. EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
  242. /**
  243. * svc_print_addr - Format rq_addr field for printing
  244. * @rqstp: svc_rqst struct containing address to print
  245. * @buf: target buffer for formatted address
  246. * @len: length of target buffer
  247. *
  248. */
  249. char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
  250. {
  251. return __svc_print_addr(svc_addr(rqstp), buf, len);
  252. }
  253. EXPORT_SYMBOL_GPL(svc_print_addr);
  254. /*
  255. * Queue up an idle server thread. Must have pool->sp_lock held.
  256. * Note: this is really a stack rather than a queue, so that we only
  257. * use as many different threads as we need, and the rest don't pollute
  258. * the cache.
  259. */
  260. static void svc_thread_enqueue(struct svc_pool *pool, struct svc_rqst *rqstp)
  261. {
  262. list_add(&rqstp->rq_list, &pool->sp_threads);
  263. }
  264. /*
  265. * Dequeue an nfsd thread. Must have pool->sp_lock held.
  266. */
  267. static void svc_thread_dequeue(struct svc_pool *pool, struct svc_rqst *rqstp)
  268. {
  269. list_del(&rqstp->rq_list);
  270. }
  271. /*
  272. * Queue up a transport with data pending. If there are idle nfsd
  273. * processes, wake 'em up.
  274. *
  275. */
  276. void svc_xprt_enqueue(struct svc_xprt *xprt)
  277. {
  278. struct svc_serv *serv = xprt->xpt_server;
  279. struct svc_pool *pool;
  280. struct svc_rqst *rqstp;
  281. int cpu;
  282. if (!(xprt->xpt_flags &
  283. ((1<<XPT_CONN)|(1<<XPT_DATA)|(1<<XPT_CLOSE)|(1<<XPT_DEFERRED))))
  284. return;
  285. cpu = get_cpu();
  286. pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
  287. put_cpu();
  288. spin_lock_bh(&pool->sp_lock);
  289. if (!list_empty(&pool->sp_threads) &&
  290. !list_empty(&pool->sp_sockets))
  291. printk(KERN_ERR
  292. "svc_xprt_enqueue: "
  293. "threads and transports both waiting??\n");
  294. pool->sp_stats.packets++;
  295. /* Mark transport as busy. It will remain in this state until
  296. * the provider calls svc_xprt_received. We update XPT_BUSY
  297. * atomically because it also guards against trying to enqueue
  298. * the transport twice.
  299. */
  300. if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) {
  301. /* Don't enqueue transport while already enqueued */
  302. dprintk("svc: transport %p busy, not enqueued\n", xprt);
  303. goto out_unlock;
  304. }
  305. BUG_ON(xprt->xpt_pool != NULL);
  306. xprt->xpt_pool = pool;
  307. /* Handle pending connection */
  308. if (test_bit(XPT_CONN, &xprt->xpt_flags))
  309. goto process;
  310. /* Handle close in-progress */
  311. if (test_bit(XPT_CLOSE, &xprt->xpt_flags))
  312. goto process;
  313. /* Check if we have space to reply to a request */
  314. if (!xprt->xpt_ops->xpo_has_wspace(xprt)) {
  315. /* Don't enqueue while not enough space for reply */
  316. dprintk("svc: no write space, transport %p not enqueued\n",
  317. xprt);
  318. xprt->xpt_pool = NULL;
  319. clear_bit(XPT_BUSY, &xprt->xpt_flags);
  320. goto out_unlock;
  321. }
  322. process:
  323. if (!list_empty(&pool->sp_threads)) {
  324. rqstp = list_entry(pool->sp_threads.next,
  325. struct svc_rqst,
  326. rq_list);
  327. dprintk("svc: transport %p served by daemon %p\n",
  328. xprt, rqstp);
  329. svc_thread_dequeue(pool, rqstp);
  330. if (rqstp->rq_xprt)
  331. printk(KERN_ERR
  332. "svc_xprt_enqueue: server %p, rq_xprt=%p!\n",
  333. rqstp, rqstp->rq_xprt);
  334. rqstp->rq_xprt = xprt;
  335. svc_xprt_get(xprt);
  336. rqstp->rq_reserved = serv->sv_max_mesg;
  337. atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
  338. pool->sp_stats.threads_woken++;
  339. BUG_ON(xprt->xpt_pool != pool);
  340. wake_up(&rqstp->rq_wait);
  341. } else {
  342. dprintk("svc: transport %p put into queue\n", xprt);
  343. list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
  344. pool->sp_stats.sockets_queued++;
  345. BUG_ON(xprt->xpt_pool != pool);
  346. }
  347. out_unlock:
  348. spin_unlock_bh(&pool->sp_lock);
  349. }
  350. EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
  351. /*
  352. * Dequeue the first transport. Must be called with the pool->sp_lock held.
  353. */
  354. static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
  355. {
  356. struct svc_xprt *xprt;
  357. if (list_empty(&pool->sp_sockets))
  358. return NULL;
  359. xprt = list_entry(pool->sp_sockets.next,
  360. struct svc_xprt, xpt_ready);
  361. list_del_init(&xprt->xpt_ready);
  362. dprintk("svc: transport %p dequeued, inuse=%d\n",
  363. xprt, atomic_read(&xprt->xpt_ref.refcount));
  364. return xprt;
  365. }
  366. /*
  367. * svc_xprt_received conditionally queues the transport for processing
  368. * by another thread. The caller must hold the XPT_BUSY bit and must
  369. * not thereafter touch transport data.
  370. *
  371. * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
  372. * insufficient) data.
  373. */
  374. void svc_xprt_received(struct svc_xprt *xprt)
  375. {
  376. BUG_ON(!test_bit(XPT_BUSY, &xprt->xpt_flags));
  377. xprt->xpt_pool = NULL;
  378. clear_bit(XPT_BUSY, &xprt->xpt_flags);
  379. svc_xprt_enqueue(xprt);
  380. }
  381. EXPORT_SYMBOL_GPL(svc_xprt_received);
  382. /**
  383. * svc_reserve - change the space reserved for the reply to a request.
  384. * @rqstp: The request in question
  385. * @space: new max space to reserve
  386. *
  387. * Each request reserves some space on the output queue of the transport
  388. * to make sure the reply fits. This function reduces that reserved
  389. * space to be the amount of space used already, plus @space.
  390. *
  391. */
  392. void svc_reserve(struct svc_rqst *rqstp, int space)
  393. {
  394. space += rqstp->rq_res.head[0].iov_len;
  395. if (space < rqstp->rq_reserved) {
  396. struct svc_xprt *xprt = rqstp->rq_xprt;
  397. atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
  398. rqstp->rq_reserved = space;
  399. svc_xprt_enqueue(xprt);
  400. }
  401. }
  402. EXPORT_SYMBOL_GPL(svc_reserve);
  403. static void svc_xprt_release(struct svc_rqst *rqstp)
  404. {
  405. struct svc_xprt *xprt = rqstp->rq_xprt;
  406. rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
  407. kfree(rqstp->rq_deferred);
  408. rqstp->rq_deferred = NULL;
  409. svc_free_res_pages(rqstp);
  410. rqstp->rq_res.page_len = 0;
  411. rqstp->rq_res.page_base = 0;
  412. /* Reset response buffer and release
  413. * the reservation.
  414. * But first, check that enough space was reserved
  415. * for the reply, otherwise we have a bug!
  416. */
  417. if ((rqstp->rq_res.len) > rqstp->rq_reserved)
  418. printk(KERN_ERR "RPC request reserved %d but used %d\n",
  419. rqstp->rq_reserved,
  420. rqstp->rq_res.len);
  421. rqstp->rq_res.head[0].iov_len = 0;
  422. svc_reserve(rqstp, 0);
  423. rqstp->rq_xprt = NULL;
  424. svc_xprt_put(xprt);
  425. }
  426. /*
  427. * External function to wake up a server waiting for data
  428. * This really only makes sense for services like lockd
  429. * which have exactly one thread anyway.
  430. */
  431. void svc_wake_up(struct svc_serv *serv)
  432. {
  433. struct svc_rqst *rqstp;
  434. unsigned int i;
  435. struct svc_pool *pool;
  436. for (i = 0; i < serv->sv_nrpools; i++) {
  437. pool = &serv->sv_pools[i];
  438. spin_lock_bh(&pool->sp_lock);
  439. if (!list_empty(&pool->sp_threads)) {
  440. rqstp = list_entry(pool->sp_threads.next,
  441. struct svc_rqst,
  442. rq_list);
  443. dprintk("svc: daemon %p woken up.\n", rqstp);
  444. /*
  445. svc_thread_dequeue(pool, rqstp);
  446. rqstp->rq_xprt = NULL;
  447. */
  448. wake_up(&rqstp->rq_wait);
  449. }
  450. spin_unlock_bh(&pool->sp_lock);
  451. }
  452. }
  453. EXPORT_SYMBOL_GPL(svc_wake_up);
  454. int svc_port_is_privileged(struct sockaddr *sin)
  455. {
  456. switch (sin->sa_family) {
  457. case AF_INET:
  458. return ntohs(((struct sockaddr_in *)sin)->sin_port)
  459. < PROT_SOCK;
  460. case AF_INET6:
  461. return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
  462. < PROT_SOCK;
  463. default:
  464. return 0;
  465. }
  466. }
  467. /*
  468. * Make sure that we don't have too many active connections. If we have,
  469. * something must be dropped. It's not clear what will happen if we allow
  470. * "too many" connections, but when dealing with network-facing software,
  471. * we have to code defensively. Here we do that by imposing hard limits.
  472. *
  473. * There's no point in trying to do random drop here for DoS
  474. * prevention. The NFS clients does 1 reconnect in 15 seconds. An
  475. * attacker can easily beat that.
  476. *
  477. * The only somewhat efficient mechanism would be if drop old
  478. * connections from the same IP first. But right now we don't even
  479. * record the client IP in svc_sock.
  480. *
  481. * single-threaded services that expect a lot of clients will probably
  482. * need to set sv_maxconn to override the default value which is based
  483. * on the number of threads
  484. */
  485. static void svc_check_conn_limits(struct svc_serv *serv)
  486. {
  487. unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
  488. (serv->sv_nrthreads+3) * 20;
  489. if (serv->sv_tmpcnt > limit) {
  490. struct svc_xprt *xprt = NULL;
  491. spin_lock_bh(&serv->sv_lock);
  492. if (!list_empty(&serv->sv_tempsocks)) {
  493. if (net_ratelimit()) {
  494. /* Try to help the admin */
  495. printk(KERN_NOTICE "%s: too many open "
  496. "connections, consider increasing %s\n",
  497. serv->sv_name, serv->sv_maxconn ?
  498. "the max number of connections." :
  499. "the number of threads.");
  500. }
  501. /*
  502. * Always select the oldest connection. It's not fair,
  503. * but so is life
  504. */
  505. xprt = list_entry(serv->sv_tempsocks.prev,
  506. struct svc_xprt,
  507. xpt_list);
  508. set_bit(XPT_CLOSE, &xprt->xpt_flags);
  509. svc_xprt_get(xprt);
  510. }
  511. spin_unlock_bh(&serv->sv_lock);
  512. if (xprt) {
  513. svc_xprt_enqueue(xprt);
  514. svc_xprt_put(xprt);
  515. }
  516. }
  517. }
  518. /*
  519. * Receive the next request on any transport. This code is carefully
  520. * organised not to touch any cachelines in the shared svc_serv
  521. * structure, only cachelines in the local svc_pool.
  522. */
  523. int svc_recv(struct svc_rqst *rqstp, long timeout)
  524. {
  525. struct svc_xprt *xprt = NULL;
  526. struct svc_serv *serv = rqstp->rq_server;
  527. struct svc_pool *pool = rqstp->rq_pool;
  528. int len, i;
  529. int pages;
  530. struct xdr_buf *arg;
  531. DECLARE_WAITQUEUE(wait, current);
  532. long time_left;
  533. dprintk("svc: server %p waiting for data (to = %ld)\n",
  534. rqstp, timeout);
  535. if (rqstp->rq_xprt)
  536. printk(KERN_ERR
  537. "svc_recv: service %p, transport not NULL!\n",
  538. rqstp);
  539. if (waitqueue_active(&rqstp->rq_wait))
  540. printk(KERN_ERR
  541. "svc_recv: service %p, wait queue active!\n",
  542. rqstp);
  543. /* now allocate needed pages. If we get a failure, sleep briefly */
  544. pages = (serv->sv_max_mesg + PAGE_SIZE) / PAGE_SIZE;
  545. for (i = 0; i < pages ; i++)
  546. while (rqstp->rq_pages[i] == NULL) {
  547. struct page *p = alloc_page(GFP_KERNEL);
  548. if (!p) {
  549. set_current_state(TASK_INTERRUPTIBLE);
  550. if (signalled() || kthread_should_stop()) {
  551. set_current_state(TASK_RUNNING);
  552. return -EINTR;
  553. }
  554. schedule_timeout(msecs_to_jiffies(500));
  555. }
  556. rqstp->rq_pages[i] = p;
  557. }
  558. rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
  559. BUG_ON(pages >= RPCSVC_MAXPAGES);
  560. /* Make arg->head point to first page and arg->pages point to rest */
  561. arg = &rqstp->rq_arg;
  562. arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
  563. arg->head[0].iov_len = PAGE_SIZE;
  564. arg->pages = rqstp->rq_pages + 1;
  565. arg->page_base = 0;
  566. /* save at least one page for response */
  567. arg->page_len = (pages-2)*PAGE_SIZE;
  568. arg->len = (pages-1)*PAGE_SIZE;
  569. arg->tail[0].iov_len = 0;
  570. try_to_freeze();
  571. cond_resched();
  572. if (signalled() || kthread_should_stop())
  573. return -EINTR;
  574. /* Normally we will wait up to 5 seconds for any required
  575. * cache information to be provided.
  576. */
  577. rqstp->rq_chandle.thread_wait = 5*HZ;
  578. spin_lock_bh(&pool->sp_lock);
  579. xprt = svc_xprt_dequeue(pool);
  580. if (xprt) {
  581. rqstp->rq_xprt = xprt;
  582. svc_xprt_get(xprt);
  583. rqstp->rq_reserved = serv->sv_max_mesg;
  584. atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
  585. /* As there is a shortage of threads and this request
  586. * had to be queued, don't allow the thread to wait so
  587. * long for cache updates.
  588. */
  589. rqstp->rq_chandle.thread_wait = 1*HZ;
  590. } else {
  591. /* No data pending. Go to sleep */
  592. svc_thread_enqueue(pool, rqstp);
  593. /*
  594. * We have to be able to interrupt this wait
  595. * to bring down the daemons ...
  596. */
  597. set_current_state(TASK_INTERRUPTIBLE);
  598. /*
  599. * checking kthread_should_stop() here allows us to avoid
  600. * locking and signalling when stopping kthreads that call
  601. * svc_recv. If the thread has already been woken up, then
  602. * we can exit here without sleeping. If not, then it
  603. * it'll be woken up quickly during the schedule_timeout
  604. */
  605. if (kthread_should_stop()) {
  606. set_current_state(TASK_RUNNING);
  607. spin_unlock_bh(&pool->sp_lock);
  608. return -EINTR;
  609. }
  610. add_wait_queue(&rqstp->rq_wait, &wait);
  611. spin_unlock_bh(&pool->sp_lock);
  612. time_left = schedule_timeout(timeout);
  613. try_to_freeze();
  614. spin_lock_bh(&pool->sp_lock);
  615. remove_wait_queue(&rqstp->rq_wait, &wait);
  616. if (!time_left)
  617. pool->sp_stats.threads_timedout++;
  618. xprt = rqstp->rq_xprt;
  619. if (!xprt) {
  620. svc_thread_dequeue(pool, rqstp);
  621. spin_unlock_bh(&pool->sp_lock);
  622. dprintk("svc: server %p, no data yet\n", rqstp);
  623. if (signalled() || kthread_should_stop())
  624. return -EINTR;
  625. else
  626. return -EAGAIN;
  627. }
  628. }
  629. spin_unlock_bh(&pool->sp_lock);
  630. len = 0;
  631. if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
  632. dprintk("svc_recv: found XPT_CLOSE\n");
  633. svc_delete_xprt(xprt);
  634. /* Leave XPT_BUSY set on the dead xprt: */
  635. goto out;
  636. }
  637. if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
  638. struct svc_xprt *newxpt;
  639. newxpt = xprt->xpt_ops->xpo_accept(xprt);
  640. if (newxpt) {
  641. /*
  642. * We know this module_get will succeed because the
  643. * listener holds a reference too
  644. */
  645. __module_get(newxpt->xpt_class->xcl_owner);
  646. svc_check_conn_limits(xprt->xpt_server);
  647. spin_lock_bh(&serv->sv_lock);
  648. set_bit(XPT_TEMP, &newxpt->xpt_flags);
  649. list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
  650. serv->sv_tmpcnt++;
  651. if (serv->sv_temptimer.function == NULL) {
  652. /* setup timer to age temp transports */
  653. setup_timer(&serv->sv_temptimer,
  654. svc_age_temp_xprts,
  655. (unsigned long)serv);
  656. mod_timer(&serv->sv_temptimer,
  657. jiffies + svc_conn_age_period * HZ);
  658. }
  659. spin_unlock_bh(&serv->sv_lock);
  660. svc_xprt_received(newxpt);
  661. }
  662. } else {
  663. dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
  664. rqstp, pool->sp_id, xprt,
  665. atomic_read(&xprt->xpt_ref.refcount));
  666. rqstp->rq_deferred = svc_deferred_dequeue(xprt);
  667. if (rqstp->rq_deferred)
  668. len = svc_deferred_recv(rqstp);
  669. else
  670. len = xprt->xpt_ops->xpo_recvfrom(rqstp);
  671. dprintk("svc: got len=%d\n", len);
  672. }
  673. svc_xprt_received(xprt);
  674. /* No data, incomplete (TCP) read, or accept() */
  675. if (len == 0 || len == -EAGAIN)
  676. goto out;
  677. clear_bit(XPT_OLD, &xprt->xpt_flags);
  678. rqstp->rq_secure = svc_port_is_privileged(svc_addr(rqstp));
  679. rqstp->rq_chandle.defer = svc_defer;
  680. if (serv->sv_stats)
  681. serv->sv_stats->netcnt++;
  682. return len;
  683. out:
  684. rqstp->rq_res.len = 0;
  685. svc_xprt_release(rqstp);
  686. return -EAGAIN;
  687. }
  688. EXPORT_SYMBOL_GPL(svc_recv);
  689. /*
  690. * Drop request
  691. */
  692. void svc_drop(struct svc_rqst *rqstp)
  693. {
  694. dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
  695. svc_xprt_release(rqstp);
  696. }
  697. EXPORT_SYMBOL_GPL(svc_drop);
  698. /*
  699. * Return reply to client.
  700. */
  701. int svc_send(struct svc_rqst *rqstp)
  702. {
  703. struct svc_xprt *xprt;
  704. int len;
  705. struct xdr_buf *xb;
  706. xprt = rqstp->rq_xprt;
  707. if (!xprt)
  708. return -EFAULT;
  709. /* release the receive skb before sending the reply */
  710. rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
  711. /* calculate over-all length */
  712. xb = &rqstp->rq_res;
  713. xb->len = xb->head[0].iov_len +
  714. xb->page_len +
  715. xb->tail[0].iov_len;
  716. /* Grab mutex to serialize outgoing data. */
  717. mutex_lock(&xprt->xpt_mutex);
  718. if (test_bit(XPT_DEAD, &xprt->xpt_flags))
  719. len = -ENOTCONN;
  720. else
  721. len = xprt->xpt_ops->xpo_sendto(rqstp);
  722. mutex_unlock(&xprt->xpt_mutex);
  723. rpc_wake_up(&xprt->xpt_bc_pending);
  724. svc_xprt_release(rqstp);
  725. if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
  726. return 0;
  727. return len;
  728. }
  729. /*
  730. * Timer function to close old temporary transports, using
  731. * a mark-and-sweep algorithm.
  732. */
  733. static void svc_age_temp_xprts(unsigned long closure)
  734. {
  735. struct svc_serv *serv = (struct svc_serv *)closure;
  736. struct svc_xprt *xprt;
  737. struct list_head *le, *next;
  738. LIST_HEAD(to_be_aged);
  739. dprintk("svc_age_temp_xprts\n");
  740. if (!spin_trylock_bh(&serv->sv_lock)) {
  741. /* busy, try again 1 sec later */
  742. dprintk("svc_age_temp_xprts: busy\n");
  743. mod_timer(&serv->sv_temptimer, jiffies + HZ);
  744. return;
  745. }
  746. list_for_each_safe(le, next, &serv->sv_tempsocks) {
  747. xprt = list_entry(le, struct svc_xprt, xpt_list);
  748. /* First time through, just mark it OLD. Second time
  749. * through, close it. */
  750. if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
  751. continue;
  752. if (atomic_read(&xprt->xpt_ref.refcount) > 1 ||
  753. test_bit(XPT_BUSY, &xprt->xpt_flags))
  754. continue;
  755. svc_xprt_get(xprt);
  756. list_move(le, &to_be_aged);
  757. set_bit(XPT_CLOSE, &xprt->xpt_flags);
  758. set_bit(XPT_DETACHED, &xprt->xpt_flags);
  759. }
  760. spin_unlock_bh(&serv->sv_lock);
  761. while (!list_empty(&to_be_aged)) {
  762. le = to_be_aged.next;
  763. /* fiddling the xpt_list node is safe 'cos we're XPT_DETACHED */
  764. list_del_init(le);
  765. xprt = list_entry(le, struct svc_xprt, xpt_list);
  766. dprintk("queuing xprt %p for closing\n", xprt);
  767. /* a thread will dequeue and close it soon */
  768. svc_xprt_enqueue(xprt);
  769. svc_xprt_put(xprt);
  770. }
  771. mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
  772. }
  773. static void call_xpt_users(struct svc_xprt *xprt)
  774. {
  775. struct svc_xpt_user *u;
  776. spin_lock(&xprt->xpt_lock);
  777. while (!list_empty(&xprt->xpt_users)) {
  778. u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
  779. list_del(&u->list);
  780. u->callback(u);
  781. }
  782. spin_unlock(&xprt->xpt_lock);
  783. }
  784. /*
  785. * Remove a dead transport
  786. */
  787. void svc_delete_xprt(struct svc_xprt *xprt)
  788. {
  789. struct svc_serv *serv = xprt->xpt_server;
  790. struct svc_deferred_req *dr;
  791. /* Only do this once */
  792. if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
  793. BUG();
  794. dprintk("svc: svc_delete_xprt(%p)\n", xprt);
  795. xprt->xpt_ops->xpo_detach(xprt);
  796. spin_lock_bh(&serv->sv_lock);
  797. if (!test_and_set_bit(XPT_DETACHED, &xprt->xpt_flags))
  798. list_del_init(&xprt->xpt_list);
  799. /*
  800. * We used to delete the transport from whichever list
  801. * it's sk_xprt.xpt_ready node was on, but we don't actually
  802. * need to. This is because the only time we're called
  803. * while still attached to a queue, the queue itself
  804. * is about to be destroyed (in svc_destroy).
  805. */
  806. if (test_bit(XPT_TEMP, &xprt->xpt_flags))
  807. serv->sv_tmpcnt--;
  808. spin_unlock_bh(&serv->sv_lock);
  809. while ((dr = svc_deferred_dequeue(xprt)) != NULL)
  810. kfree(dr);
  811. call_xpt_users(xprt);
  812. svc_xprt_put(xprt);
  813. }
  814. void svc_close_xprt(struct svc_xprt *xprt)
  815. {
  816. set_bit(XPT_CLOSE, &xprt->xpt_flags);
  817. if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
  818. /* someone else will have to effect the close */
  819. return;
  820. /*
  821. * We expect svc_close_xprt() to work even when no threads are
  822. * running (e.g., while configuring the server before starting
  823. * any threads), so if the transport isn't busy, we delete
  824. * it ourself:
  825. */
  826. svc_delete_xprt(xprt);
  827. }
  828. EXPORT_SYMBOL_GPL(svc_close_xprt);
  829. void svc_close_all(struct list_head *xprt_list)
  830. {
  831. struct svc_xprt *xprt;
  832. struct svc_xprt *tmp;
  833. /*
  834. * The server is shutting down, and no more threads are running.
  835. * svc_xprt_enqueue() might still be running, but at worst it
  836. * will re-add the xprt to sp_sockets, which will soon get
  837. * freed. So we don't bother with any more locking, and don't
  838. * leave the close to the (nonexistent) server threads:
  839. */
  840. list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) {
  841. set_bit(XPT_CLOSE, &xprt->xpt_flags);
  842. svc_delete_xprt(xprt);
  843. }
  844. }
  845. /*
  846. * Handle defer and revisit of requests
  847. */
  848. static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
  849. {
  850. struct svc_deferred_req *dr =
  851. container_of(dreq, struct svc_deferred_req, handle);
  852. struct svc_xprt *xprt = dr->xprt;
  853. spin_lock(&xprt->xpt_lock);
  854. set_bit(XPT_DEFERRED, &xprt->xpt_flags);
  855. if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
  856. spin_unlock(&xprt->xpt_lock);
  857. dprintk("revisit canceled\n");
  858. svc_xprt_put(xprt);
  859. kfree(dr);
  860. return;
  861. }
  862. dprintk("revisit queued\n");
  863. dr->xprt = NULL;
  864. list_add(&dr->handle.recent, &xprt->xpt_deferred);
  865. spin_unlock(&xprt->xpt_lock);
  866. svc_xprt_enqueue(xprt);
  867. svc_xprt_put(xprt);
  868. }
  869. /*
  870. * Save the request off for later processing. The request buffer looks
  871. * like this:
  872. *
  873. * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
  874. *
  875. * This code can only handle requests that consist of an xprt-header
  876. * and rpc-header.
  877. */
  878. static struct cache_deferred_req *svc_defer(struct cache_req *req)
  879. {
  880. struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
  881. struct svc_deferred_req *dr;
  882. if (rqstp->rq_arg.page_len || !rqstp->rq_usedeferral)
  883. return NULL; /* if more than a page, give up FIXME */
  884. if (rqstp->rq_deferred) {
  885. dr = rqstp->rq_deferred;
  886. rqstp->rq_deferred = NULL;
  887. } else {
  888. size_t skip;
  889. size_t size;
  890. /* FIXME maybe discard if size too large */
  891. size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
  892. dr = kmalloc(size, GFP_KERNEL);
  893. if (dr == NULL)
  894. return NULL;
  895. dr->handle.owner = rqstp->rq_server;
  896. dr->prot = rqstp->rq_prot;
  897. memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
  898. dr->addrlen = rqstp->rq_addrlen;
  899. dr->daddr = rqstp->rq_daddr;
  900. dr->argslen = rqstp->rq_arg.len >> 2;
  901. dr->xprt_hlen = rqstp->rq_xprt_hlen;
  902. /* back up head to the start of the buffer and copy */
  903. skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
  904. memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
  905. dr->argslen << 2);
  906. }
  907. svc_xprt_get(rqstp->rq_xprt);
  908. dr->xprt = rqstp->rq_xprt;
  909. dr->handle.revisit = svc_revisit;
  910. return &dr->handle;
  911. }
  912. /*
  913. * recv data from a deferred request into an active one
  914. */
  915. static int svc_deferred_recv(struct svc_rqst *rqstp)
  916. {
  917. struct svc_deferred_req *dr = rqstp->rq_deferred;
  918. /* setup iov_base past transport header */
  919. rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
  920. /* The iov_len does not include the transport header bytes */
  921. rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
  922. rqstp->rq_arg.page_len = 0;
  923. /* The rq_arg.len includes the transport header bytes */
  924. rqstp->rq_arg.len = dr->argslen<<2;
  925. rqstp->rq_prot = dr->prot;
  926. memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
  927. rqstp->rq_addrlen = dr->addrlen;
  928. /* Save off transport header len in case we get deferred again */
  929. rqstp->rq_xprt_hlen = dr->xprt_hlen;
  930. rqstp->rq_daddr = dr->daddr;
  931. rqstp->rq_respages = rqstp->rq_pages;
  932. return (dr->argslen<<2) - dr->xprt_hlen;
  933. }
  934. static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
  935. {
  936. struct svc_deferred_req *dr = NULL;
  937. if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
  938. return NULL;
  939. spin_lock(&xprt->xpt_lock);
  940. if (!list_empty(&xprt->xpt_deferred)) {
  941. dr = list_entry(xprt->xpt_deferred.next,
  942. struct svc_deferred_req,
  943. handle.recent);
  944. list_del_init(&dr->handle.recent);
  945. } else
  946. clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
  947. spin_unlock(&xprt->xpt_lock);
  948. return dr;
  949. }
  950. /**
  951. * svc_find_xprt - find an RPC transport instance
  952. * @serv: pointer to svc_serv to search
  953. * @xcl_name: C string containing transport's class name
  954. * @af: Address family of transport's local address
  955. * @port: transport's IP port number
  956. *
  957. * Return the transport instance pointer for the endpoint accepting
  958. * connections/peer traffic from the specified transport class,
  959. * address family and port.
  960. *
  961. * Specifying 0 for the address family or port is effectively a
  962. * wild-card, and will result in matching the first transport in the
  963. * service's list that has a matching class name.
  964. */
  965. struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
  966. const sa_family_t af, const unsigned short port)
  967. {
  968. struct svc_xprt *xprt;
  969. struct svc_xprt *found = NULL;
  970. /* Sanity check the args */
  971. if (serv == NULL || xcl_name == NULL)
  972. return found;
  973. spin_lock_bh(&serv->sv_lock);
  974. list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
  975. if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
  976. continue;
  977. if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
  978. continue;
  979. if (port != 0 && port != svc_xprt_local_port(xprt))
  980. continue;
  981. found = xprt;
  982. svc_xprt_get(xprt);
  983. break;
  984. }
  985. spin_unlock_bh(&serv->sv_lock);
  986. return found;
  987. }
  988. EXPORT_SYMBOL_GPL(svc_find_xprt);
  989. static int svc_one_xprt_name(const struct svc_xprt *xprt,
  990. char *pos, int remaining)
  991. {
  992. int len;
  993. len = snprintf(pos, remaining, "%s %u\n",
  994. xprt->xpt_class->xcl_name,
  995. svc_xprt_local_port(xprt));
  996. if (len >= remaining)
  997. return -ENAMETOOLONG;
  998. return len;
  999. }
  1000. /**
  1001. * svc_xprt_names - format a buffer with a list of transport names
  1002. * @serv: pointer to an RPC service
  1003. * @buf: pointer to a buffer to be filled in
  1004. * @buflen: length of buffer to be filled in
  1005. *
  1006. * Fills in @buf with a string containing a list of transport names,
  1007. * each name terminated with '\n'.
  1008. *
  1009. * Returns positive length of the filled-in string on success; otherwise
  1010. * a negative errno value is returned if an error occurs.
  1011. */
  1012. int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
  1013. {
  1014. struct svc_xprt *xprt;
  1015. int len, totlen;
  1016. char *pos;
  1017. /* Sanity check args */
  1018. if (!serv)
  1019. return 0;
  1020. spin_lock_bh(&serv->sv_lock);
  1021. pos = buf;
  1022. totlen = 0;
  1023. list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
  1024. len = svc_one_xprt_name(xprt, pos, buflen - totlen);
  1025. if (len < 0) {
  1026. *buf = '\0';
  1027. totlen = len;
  1028. }
  1029. if (len <= 0)
  1030. break;
  1031. pos += len;
  1032. totlen += len;
  1033. }
  1034. spin_unlock_bh(&serv->sv_lock);
  1035. return totlen;
  1036. }
  1037. EXPORT_SYMBOL_GPL(svc_xprt_names);
  1038. /*----------------------------------------------------------------------------*/
  1039. static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
  1040. {
  1041. unsigned int pidx = (unsigned int)*pos;
  1042. struct svc_serv *serv = m->private;
  1043. dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
  1044. if (!pidx)
  1045. return SEQ_START_TOKEN;
  1046. return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
  1047. }
  1048. static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
  1049. {
  1050. struct svc_pool *pool = p;
  1051. struct svc_serv *serv = m->private;
  1052. dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
  1053. if (p == SEQ_START_TOKEN) {
  1054. pool = &serv->sv_pools[0];
  1055. } else {
  1056. unsigned int pidx = (pool - &serv->sv_pools[0]);
  1057. if (pidx < serv->sv_nrpools-1)
  1058. pool = &serv->sv_pools[pidx+1];
  1059. else
  1060. pool = NULL;
  1061. }
  1062. ++*pos;
  1063. return pool;
  1064. }
  1065. static void svc_pool_stats_stop(struct seq_file *m, void *p)
  1066. {
  1067. }
  1068. static int svc_pool_stats_show(struct seq_file *m, void *p)
  1069. {
  1070. struct svc_pool *pool = p;
  1071. if (p == SEQ_START_TOKEN) {
  1072. seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
  1073. return 0;
  1074. }
  1075. seq_printf(m, "%u %lu %lu %lu %lu\n",
  1076. pool->sp_id,
  1077. pool->sp_stats.packets,
  1078. pool->sp_stats.sockets_queued,
  1079. pool->sp_stats.threads_woken,
  1080. pool->sp_stats.threads_timedout);
  1081. return 0;
  1082. }
  1083. static const struct seq_operations svc_pool_stats_seq_ops = {
  1084. .start = svc_pool_stats_start,
  1085. .next = svc_pool_stats_next,
  1086. .stop = svc_pool_stats_stop,
  1087. .show = svc_pool_stats_show,
  1088. };
  1089. int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
  1090. {
  1091. int err;
  1092. err = seq_open(file, &svc_pool_stats_seq_ops);
  1093. if (!err)
  1094. ((struct seq_file *) file->private_data)->private = serv;
  1095. return err;
  1096. }
  1097. EXPORT_SYMBOL(svc_pool_stats_open);
  1098. /*----------------------------------------------------------------------------*/