nginx 0.8.33 *) Security: now nginx/Windows ignores trailing spaces in URI. Thanks to Dan Crowley, Core Security Technologies. *) Security: now nginx/Windows ignores short files names. Thanks to Dan Crowley, Core Security Technologies. *) Change: now keepalive connections after POST requests are not disabled for MSIE 7.0+. Thanks to Adam Lounds. *) Workaround: now keepalive connections are disabled for Safari. Thanks to Joshua Sierles. *) Bugfix: if a proxied or FastCGI request was internally redirected to another proxied or FastCGI location, then $upstream_response_time variable may have abnormally large value; the bug had appeared in 0.8.7. *) Bugfix: a segmentation fault might occur in a worker process, while discarding a request body; the bug had appeared in 0.8.11.

/*
 * Copyright (C) Igor Sysoev
 */


#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

}