nginx 0.2.2 *) Feature: the "config errmsg" command of the ngx_http_ssi_module. *) Change: the ngx_http_geo_module variables can be overridden by the "set" directive. *) Feature: the "ssl_protocols" and "ssl_prefer_server_ciphers" directives of the ngx_http_ssl_module and ngx_imap_ssl_module. *) Bugfix: the ngx_http_autoindex_module did not show correctly the long file names; *) Bugfix: the ngx_http_autoindex_module now do not show the files starting by dot. *) Bugfix: if the SSL handshake failed then another connection may be closed too. Thanks to Rob Mueller. *) Bugfix: the export versions of MSIE 5.x could not connect via HTTPS.

/*
 * Copyright (C) Igor Sysoev
 */


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


/*
 * TODO: the P4 optimized assembler version with the "pause" operation
 */

void ngx_spinlock(ngx_atomic_t *lock, ngx_uint_t spin)
{

#if (NGX_HAVE_ATOMIC_OPS)

    ngx_uint_t  tries;

    tries = 0;

    for ( ;; ) {

        if (*lock) {
            if (ngx_ncpu > 1 && tries++ < spin) {
                continue;
            }

            ngx_sched_yield();

            tries = 0;

        } else {
            if (ngx_atomic_cmp_set(lock, 0, 1)) {
                return;
            }
        }
    }

#else

#if (NGX_THREADS)

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

#endif

#endif

}