nginx 0.3.12 *) Security: if nginx was built with the ngx_http_realip_module and the "satisfy_any on" directive was used, then access and authorization directives did not work. The ngx_http_realip_module was not built and is not built by default. *) Change: the "$time_gmt" variable name was changed to "$time_local". *) Change: the "proxy_header_buffer_size" and "fastcgi_header_buffer_size" directives was renamed to the "proxy_buffer_size" and "fastcgi_buffer_size" directives. *) Feature: the ngx_http_memcached_module. *) Feature: the "proxy_buffering" directive. *) Bugfix: the changes in accept mutex handling when the "rtsig" method was used; bug appeared in 0.3.0. *) Bugfix: if the client sent the "Transfer-Encoding: chunked" header line, then nginx returns the 411 error. *) Bugfix: if the "auth_basic" directive was inherited from the http level, then the realm in the "WWW-Authenticate" header line was without the "Basic realm" text. *) Bugfix: if the "combined" format was explicitly specified in the "access_log" directive, then the empty lines was written to the log; bug appeared in 0.3.8. *) Bugfix: nginx did not run on the sparc platform under any OS except Solaris. *) Bugfix: now it is not necessary to place space between the quoted string and closing bracket in the "if" directive.

/*
 * 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

}