view src/event/ngx_event_posted.h @ 3755:76e3a93821b1

fix race condition if during reconfiguration two cache managers try to delete old inactive entries: one of them removes a entry just locked by other manager from the queue and the rbtree as long inactive entry, causes the latter manager to segfault leaving cache mutex locked, the bug has been introduced in r3727
author Igor Sysoev <igor@sysoev.ru>
date Thu, 02 Sep 2010 14:31:47 +0000
parents 9c2f3ed7a247
children d620f497c50f
line wrap: on
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/*
 * Copyright (C) Igor Sysoev
 */


#ifndef _NGX_EVENT_POSTED_H_INCLUDED_
#define _NGX_EVENT_POSTED_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


#if (NGX_THREADS)
extern ngx_mutex_t  *ngx_posted_events_mutex;
#endif


#define ngx_locked_post_event(ev, queue)                                      \
                                                                              \
    if (ev->prev == NULL) {                                                   \
        ev->next = (ngx_event_t *) *queue;                                    \
        ev->prev = (ngx_event_t **) queue;                                    \
        *queue = ev;                                                          \
                                                                              \
        if (ev->next) {                                                       \
            ev->next->prev = &ev->next;                                       \
        }                                                                     \
                                                                              \
        ngx_log_debug1(NGX_LOG_DEBUG_CORE, ev->log, 0, "post event %p", ev);  \
                                                                              \
    } else  {                                                                 \
        ngx_log_debug1(NGX_LOG_DEBUG_CORE, ev->log, 0,                        \
                       "update posted event %p", ev);                         \
    }


#define ngx_post_event(ev, queue)                                             \
                                                                              \
    ngx_mutex_lock(ngx_posted_events_mutex);                                  \
    ngx_locked_post_event(ev, queue);                                         \
    ngx_mutex_unlock(ngx_posted_events_mutex);


#define ngx_delete_posted_event(ev)                                           \
                                                                              \
    *(ev->prev) = ev->next;                                                   \
                                                                              \
    if (ev->next) {                                                           \
        ev->next->prev = ev->prev;                                            \
    }                                                                         \
                                                                              \
    ev->prev = NULL;                                                          \
    ngx_log_debug1(NGX_LOG_DEBUG_CORE, ev->log, 0,                            \
                   "delete posted event %p", ev);



void ngx_event_process_posted(ngx_cycle_t *cycle,
    ngx_thread_volatile ngx_event_t **posted);
void ngx_wakeup_worker_thread(ngx_cycle_t *cycle);

#if (NGX_THREADS)
ngx_int_t ngx_event_thread_process_posted(ngx_cycle_t *cycle);
#endif


extern ngx_thread_volatile ngx_event_t  *ngx_posted_accept_events;
extern ngx_thread_volatile ngx_event_t  *ngx_posted_events;


#endif /* _NGX_EVENT_POSTED_H_INCLUDED_ */