nginx 1.0.12 *) Feature: the "TLSv1.1" and "TLSv1.2" parameters of the "ssl_protocols" directive. *) Feature: the "if" SSI command supports captures in regular expressions. *) Bugfix: the "if" SSI command did not work inside the "block" command. *) Bugfix: in AIO error handling on FreeBSD. *) Bugfix: in the OpenSSL library initialization. *) Bugfix: the "worker_cpu_affinity" directive might not work. *) Bugfix: the "limit_conn_log_level" and "limit_req_log_level" directives might not work. *) Bugfix: the "read_ahead" directive might not work combined with "try_files" and "open_file_cache". *) Bugfix: the "proxy_cache_use_stale" directive with "error" parameter did not return answer from cache if there were no live upstreams. *) Bugfix: a segmentation fault might occur in a worker process if small time was used in the "inactive" parameter of the "proxy_cache_path" directive. *) Bugfix: responses from cache might hang. *) Bugfix: in error handling while connecting to a backend. Thanks to Piotr Sikora. *) Bugfix: in the "epoll" event method. Thanks to Yichun Zhang. *) Bugfix: the $sent_http_cache_control variable might contain a wrong value if the "expires" directive was used. Thanks to Yichun Zhang. *) Bugfix: the "limit_rate" directive did not allow to use full throughput, even if limit value was very high. *) Bugfix: the "sendfile_max_chunk" directive did not work, if the "limit_rate" directive was used. *) Bugfix: nginx could not be built on Solaris; the bug had appeared in 1.0.11. *) Bugfix: in the ngx_http_scgi_module. *) Bugfix: in the ngx_http_mp4_module.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


void
ngx_spinlock(ngx_atomic_t *lock, ngx_atomic_int_t value, ngx_uint_t spin)
{

#if (NGX_HAVE_ATOMIC_OPS)

    ngx_uint_t  i, n;

    for ( ;; ) {

        if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
            return;
        }

        if (ngx_ncpu > 1) {

            for (n = 1; n < spin; n <<= 1) {

                for (i = 0; i < n; i++) {
                    ngx_cpu_pause();
                }

                if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) {
                    return;
                }
            }
        }

        ngx_sched_yield();
    }

#else

#if (NGX_THREADS)

#error ngx_spinlock() or ngx_atomic_cmp_set() are not defined !

#endif

#endif

}