cregit-Linux how code gets into the kernel

Release 4.8 net/rxrpc/call_object.c

Directory: net/rxrpc
/* RxRPC individual remote procedure call handling
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/circ_buf.h>
#include <linux/spinlock_types.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"

/*
 * Maximum lifetime of a call (in jiffies).
 */

unsigned int rxrpc_max_call_lifetime = 60 * HZ;

/*
 * Time till dead call expires after last use (in jiffies).
 */

unsigned int rxrpc_dead_call_expiry = 2 * HZ;


const char *const rxrpc_call_states[NR__RXRPC_CALL_STATES] = {
	[RXRPC_CALL_UNINITIALISED]		= "Uninit",
	[RXRPC_CALL_CLIENT_AWAIT_CONN]		= "ClWtConn",
	[RXRPC_CALL_CLIENT_SEND_REQUEST]	= "ClSndReq",
	[RXRPC_CALL_CLIENT_AWAIT_REPLY]		= "ClAwtRpl",
	[RXRPC_CALL_CLIENT_RECV_REPLY]		= "ClRcvRpl",
	[RXRPC_CALL_CLIENT_FINAL_ACK]		= "ClFnlACK",
	[RXRPC_CALL_SERVER_SECURING]		= "SvSecure",
	[RXRPC_CALL_SERVER_ACCEPTING]		= "SvAccept",
	[RXRPC_CALL_SERVER_RECV_REQUEST]	= "SvRcvReq",
	[RXRPC_CALL_SERVER_ACK_REQUEST]		= "SvAckReq",
	[RXRPC_CALL_SERVER_SEND_REPLY]		= "SvSndRpl",
	[RXRPC_CALL_SERVER_AWAIT_ACK]		= "SvAwtACK",
	[RXRPC_CALL_COMPLETE]			= "Complete",
	[RXRPC_CALL_SERVER_BUSY]		= "SvBusy  ",
	[RXRPC_CALL_REMOTELY_ABORTED]		= "RmtAbort",
	[RXRPC_CALL_LOCALLY_ABORTED]		= "LocAbort",
	[RXRPC_CALL_NETWORK_ERROR]		= "NetError",
	[RXRPC_CALL_DEAD]			= "Dead    ",
};


struct kmem_cache *rxrpc_call_jar;

LIST_HEAD(rxrpc_calls);

DEFINE_RWLOCK(rxrpc_call_lock);

static void rxrpc_destroy_call(struct work_struct *work);
static void rxrpc_call_life_expired(unsigned long _call);
static void rxrpc_dead_call_expired(unsigned long _call);
static void rxrpc_ack_time_expired(unsigned long _call);
static void rxrpc_resend_time_expired(unsigned long _call);

/*
 * find an extant server call
 * - called in process context with IRQs enabled
 */

struct rxrpc_call *rxrpc_find_call_by_user_ID(struct rxrpc_sock *rx, unsigned long user_call_ID) { struct rxrpc_call *call; struct rb_node *p; _enter("%p,%lx", rx, user_call_ID); read_lock(&rx->call_lock); p = rx->calls.rb_node; while (p) { call = rb_entry(p, struct rxrpc_call, sock_node); if (user_call_ID < call->user_call_ID) p = p->rb_left; else if (user_call_ID > call->user_call_ID) p = p->rb_right; else goto found_extant_call; } read_unlock(&rx->call_lock); _leave(" = NULL"); return NULL; found_extant_call: rxrpc_get_call(call); read_unlock(&rx->call_lock); _leave(" = %p [%d]", call, atomic_read(&call->usage)); return call; }

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/* * allocate a new call */
static struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp) { struct rxrpc_call *call; call = kmem_cache_zalloc(rxrpc_call_jar, gfp); if (!call) return NULL; call->acks_winsz = 16; call->acks_window = kmalloc(call->acks_winsz * sizeof(unsigned long), gfp); if (!call->acks_window) { kmem_cache_free(rxrpc_call_jar, call); return NULL; } setup_timer(&call->lifetimer, &rxrpc_call_life_expired, (unsigned long) call); setup_timer(&call->deadspan, &rxrpc_dead_call_expired, (unsigned long) call); setup_timer(&call->ack_timer, &rxrpc_ack_time_expired, (unsigned long) call); setup_timer(&call->resend_timer, &rxrpc_resend_time_expired, (unsigned long) call); INIT_WORK(&call->destroyer, &rxrpc_destroy_call); INIT_WORK(&call->processor, &rxrpc_process_call); INIT_LIST_HEAD(&call->link); INIT_LIST_HEAD(&call->accept_link); skb_queue_head_init(&call->rx_queue); skb_queue_head_init(&call->rx_oos_queue); init_waitqueue_head(&call->tx_waitq); spin_lock_init(&call->lock); rwlock_init(&call->state_lock); atomic_set(&call->usage, 1); call->debug_id = atomic_inc_return(&rxrpc_debug_id); memset(&call->sock_node, 0xed, sizeof(call->sock_node)); call->rx_data_expect = 1; call->rx_data_eaten = 0; call->rx_first_oos = 0; call->ackr_win_top = call->rx_data_eaten + 1 + rxrpc_rx_window_size; call->creation_jif = jiffies; return call; }

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/* * Allocate a new client call. */
static struct rxrpc_call *rxrpc_alloc_client_call(struct rxrpc_sock *rx, struct sockaddr_rxrpc *srx, gfp_t gfp) { struct rxrpc_call *call; _enter(""); ASSERT(rx->local != NULL); call = rxrpc_alloc_call(gfp); if (!call) return ERR_PTR(-ENOMEM); call->state = RXRPC_CALL_CLIENT_AWAIT_CONN; sock_hold(&rx->sk); call->socket = rx; call->rx_data_post = 1; call->local = rx->local; call->service_id = srx->srx_service; call->in_clientflag = 0; _leave(" = %p", call); return call; }

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/* * Begin client call. */
static int rxrpc_begin_client_call(struct rxrpc_call *call, struct rxrpc_conn_parameters *cp, struct sockaddr_rxrpc *srx, gfp_t gfp) { int ret; /* Set up or get a connection record and set the protocol parameters, * including channel number and call ID. */ ret = rxrpc_connect_call(call, cp, srx, gfp); if (ret < 0) return ret; call->state = RXRPC_CALL_CLIENT_SEND_REQUEST; spin_lock(&call->conn->params.peer->lock); hlist_add_head(&call->error_link, &call->conn->params.peer->error_targets); spin_unlock(&call->conn->params.peer->lock); call->lifetimer.expires = jiffies + rxrpc_max_call_lifetime; add_timer(&call->lifetimer); return 0; }

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/* * set up a call for the given data * - called in process context with IRQs enabled */
struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx, struct rxrpc_conn_parameters *cp, struct sockaddr_rxrpc *srx, unsigned long user_call_ID, gfp_t gfp) { struct rxrpc_call *call, *xcall; struct rb_node *parent, **pp; int ret; _enter("%p,%lx", rx, user_call_ID); call = rxrpc_alloc_client_call(rx, srx, gfp); if (IS_ERR(call)) { _leave(" = %ld", PTR_ERR(call)); return call; } /* Publish the call, even though it is incompletely set up as yet */ call->user_call_ID = user_call_ID; __set_bit(RXRPC_CALL_HAS_USERID, &call->flags); write_lock(&rx->call_lock); pp = &rx->calls.rb_node; parent = NULL; while (*pp) { parent = *pp; xcall = rb_entry(parent, struct rxrpc_call, sock_node); if (user_call_ID < xcall->user_call_ID) pp = &(*pp)->rb_left; else if (user_call_ID > xcall->user_call_ID) pp = &(*pp)->rb_right; else goto found_user_ID_now_present; } rxrpc_get_call(call); rb_link_node(&call->sock_node, parent, pp); rb_insert_color(&call->sock_node, &rx->calls); write_unlock(&rx->call_lock); write_lock_bh(&rxrpc_call_lock); list_add_tail(&call->link, &rxrpc_calls); write_unlock_bh(&rxrpc_call_lock); ret = rxrpc_begin_client_call(call, cp, srx, gfp); if (ret < 0) goto error; _net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id); _leave(" = %p [new]", call); return call; error: write_lock(&rx->call_lock); rb_erase(&call->sock_node, &rx->calls); write_unlock(&rx->call_lock); rxrpc_put_call(call); write_lock_bh(&rxrpc_call_lock); list_del_init(&call->link); write_unlock_bh(&rxrpc_call_lock); set_bit(RXRPC_CALL_RELEASED, &call->flags); call->state = RXRPC_CALL_DEAD; rxrpc_put_call(call); _leave(" = %d", ret); return ERR_PTR(ret); /* We unexpectedly found the user ID in the list after taking * the call_lock. This shouldn't happen unless the user races * with itself and tries to add the same user ID twice at the * same time in different threads. */ found_user_ID_now_present: write_unlock(&rx->call_lock); set_bit(RXRPC_CALL_RELEASED, &call->flags); call->state = RXRPC_CALL_DEAD; rxrpc_put_call(call); _leave(" = -EEXIST [%p]", call); return ERR_PTR(-EEXIST); }

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/* * set up an incoming call * - called in process context with IRQs enabled */
struct rxrpc_call *rxrpc_incoming_call(struct rxrpc_sock *rx, struct rxrpc_connection *conn, struct sk_buff *skb) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); struct rxrpc_call *call, *candidate; u32 call_id, chan; _enter(",%d", conn->debug_id); ASSERT(rx != NULL); candidate = rxrpc_alloc_call(GFP_NOIO); if (!candidate) return ERR_PTR(-EBUSY); chan = sp->hdr.cid & RXRPC_CHANNELMASK; candidate->socket = rx; candidate->conn = conn; candidate->cid = sp->hdr.cid; candidate->call_id = sp->hdr.callNumber; candidate->channel = chan; candidate->rx_data_post = 0; candidate->state = RXRPC_CALL_SERVER_ACCEPTING; if (conn->security_ix > 0) candidate->state = RXRPC_CALL_SERVER_SECURING; spin_lock(&conn->channel_lock); /* set the channel for this call */ call = rcu_dereference_protected(conn->channels[chan].call, lockdep_is_held(&conn->channel_lock)); _debug("channel[%u] is %p", candidate->channel, call); if (call && call->call_id == sp->hdr.callNumber) { /* already set; must've been a duplicate packet */ _debug("extant call [%d]", call->state); ASSERTCMP(call->conn, ==, conn); read_lock(&call->state_lock); switch (call->state) { case RXRPC_CALL_LOCALLY_ABORTED: if (!test_and_set_bit(RXRPC_CALL_EV_ABORT, &call->events)) rxrpc_queue_call(call); case RXRPC_CALL_REMOTELY_ABORTED: read_unlock(&call->state_lock); goto aborted_call; default: rxrpc_get_call(call); read_unlock(&call->state_lock); goto extant_call; } } if (call) { /* it seems the channel is still in use from the previous call * - ditch the old binding if its call is now complete */ _debug("CALL: %u { %s }", call->debug_id, rxrpc_call_states[call->state]); if (call->state >= RXRPC_CALL_COMPLETE) { __rxrpc_disconnect_call(call); } else { spin_unlock(&conn->channel_lock); kmem_cache_free(rxrpc_call_jar, candidate); _leave(" = -EBUSY"); return ERR_PTR(-EBUSY); } } /* check the call number isn't duplicate */ _debug("check dup"); call_id = sp->hdr.callNumber; /* We just ignore calls prior to the current call ID. Terminated calls * are handled via the connection. */ if (call_id <= conn->channels[chan].call_counter) goto old_call; /* TODO: Just drop packet */ /* make the call available */ _debug("new call"); call = candidate; candidate = NULL; conn->channels[chan].call_counter = call_id; rcu_assign_pointer(conn->channels[chan].call, call); sock_hold(&rx->sk); rxrpc_get_connection(conn); spin_unlock(&conn->channel_lock); spin_lock(&conn->params.peer->lock); hlist_add_head(&call->error_link, &conn->params.peer->error_targets); spin_unlock(&conn->params.peer->lock); write_lock_bh(&rxrpc_call_lock); list_add_tail(&call->link, &rxrpc_calls); write_unlock_bh(&rxrpc_call_lock); call->local = conn->params.local; call->epoch = conn->proto.epoch; call->service_id = conn->params.service_id; call->in_clientflag = RXRPC_CLIENT_INITIATED; _net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id); call->lifetimer.expires = jiffies + rxrpc_max_call_lifetime; add_timer(&call->lifetimer); _leave(" = %p {%d} [new]", call, call->debug_id); return call; extant_call: spin_unlock(&conn->channel_lock); kmem_cache_free(rxrpc_call_jar, candidate); _leave(" = %p {%d} [extant]", call, call ? call->debug_id : -1); return call; aborted_call: spin_unlock(&conn->channel_lock); kmem_cache_free(rxrpc_call_jar, candidate); _leave(" = -ECONNABORTED"); return ERR_PTR(-ECONNABORTED); old_call: spin_unlock(&conn->channel_lock); kmem_cache_free(rxrpc_call_jar, candidate); _leave(" = -ECONNRESET [old]"); return ERR_PTR(-ECONNRESET); }

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/* * detach a call from a socket and set up for release */
void rxrpc_release_call(struct rxrpc_call *call) { struct rxrpc_connection *conn = call->conn; struct rxrpc_sock *rx = call->socket; _enter("{%d,%d,%d,%d}", call->debug_id, atomic_read(&call->usage), atomic_read(&call->ackr_not_idle), call->rx_first_oos); spin_lock_bh(&call->lock); if (test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags)) BUG(); spin_unlock_bh(&call->lock); /* dissociate from the socket * - the socket's ref on the call is passed to the death timer */ _debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn); spin_lock(&conn->params.peer->lock); hlist_del_init(&call->error_link); spin_unlock(&conn->params.peer->lock); write_lock_bh(&rx->call_lock); if (!list_empty(&call->accept_link)) { _debug("unlinking once-pending call %p { e=%lx f=%lx }", call, call->events, call->flags); ASSERT(!test_bit(RXRPC_CALL_HAS_USERID, &call->flags)); list_del_init(&call->accept_link); sk_acceptq_removed(&rx->sk); } else if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) { rb_erase(&call->sock_node, &rx->calls); memset(&call->sock_node, 0xdd, sizeof(call->sock_node)); clear_bit(RXRPC_CALL_HAS_USERID, &call->flags); } write_unlock_bh(&rx->call_lock); /* free up the channel for reuse */ write_lock_bh(&call->state_lock); if (call->state < RXRPC_CALL_COMPLETE && call->state != RXRPC_CALL_CLIENT_FINAL_ACK) { _debug("+++ ABORTING STATE %d +++\n", call->state); call->state = RXRPC_CALL_LOCALLY_ABORTED; call->local_abort = RX_CALL_DEAD; } write_unlock_bh(&call->state_lock); rxrpc_disconnect_call(call); /* clean up the Rx queue */ if (!skb_queue_empty(&call->rx_queue) || !skb_queue_empty(&call->rx_oos_queue)) { struct rxrpc_skb_priv *sp; struct sk_buff *skb; _debug("purge Rx queues"); spin_lock_bh(&call->lock); while ((skb = skb_dequeue(&call->rx_queue)) || (skb = skb_dequeue(&call->rx_oos_queue))) { spin_unlock_bh(&call->lock); sp = rxrpc_skb(skb); _debug("- zap %s %%%u #%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial, sp->hdr.seq); rxrpc_free_skb(skb); spin_lock_bh(&call->lock); } spin_unlock_bh(&call->lock); ASSERTCMP(call->state, !=, RXRPC_CALL_COMPLETE); } del_timer_sync(&call->resend_timer); del_timer_sync(&call->ack_timer); del_timer_sync(&call->lifetimer); call->deadspan.expires = jiffies + rxrpc_dead_call_expiry; add_timer(&call->deadspan); _leave(""); }

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/* * handle a dead call being ready for reaping */
static void rxrpc_dead_call_expired(unsigned long _call) { struct rxrpc_call *call = (struct rxrpc_call *) _call; _enter("{%d}", call->debug_id); write_lock_bh(&call->state_lock); call->state = RXRPC_CALL_DEAD; write_unlock_bh(&call->state_lock); rxrpc_put_call(call); }

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/* * mark a call as to be released, aborting it if it's still in progress * - called with softirqs disabled */
static void rxrpc_mark_call_released(struct rxrpc_call *call) { bool sched; write_lock(&call->state_lock); if (call->state < RXRPC_CALL_DEAD) { sched = false; if (call->state < RXRPC_CALL_COMPLETE) { _debug("abort call %p", call); call->state = RXRPC_CALL_LOCALLY_ABORTED; call->local_abort = RX_CALL_DEAD; if (!test_and_set_bit(RXRPC_CALL_EV_ABORT, &call->events)) sched = true; } if (!test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events)) sched = true; if (sched) rxrpc_queue_call(call); } write_unlock(&call->state_lock); }

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/* * release all the calls associated with a socket */
void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx) { struct rxrpc_call *call