nginx 0.8.7 *) Change: minimum supported OpenSSL version is 0.9.7. *) Change: the "ask" parameter of the "ssl_verify_client" directive was changed to the "optional" parameter and now it checks a client certificate if it was offered. Thanks to Brice Figureau. *) Feature: the $ssl_client_verify variable. Thanks to Brice Figureau. *) Feature: the "ssl_crl" directive. Thanks to Brice Figureau. *) Feature: the "proxy" parameter of the "geo" directive. *) Feature: the "image_filter" directive supports variables for setting size. *) Bugfix: the $ssl_client_cert variable usage corrupted memory; the bug had appeared in 0.7.7. Thanks to Sergey Zhuravlev. *) Bugfix: "proxy_pass_header" and "fastcgi_pass_header" directives did not pass to a client the "X-Accel-Redirect", "X-Accel-Limit-Rate", "X-Accel-Buffering", and "X-Accel-Charset" lines from backend response header. Thanks to Maxim Dounin. *) Bugfix: in handling "Last-Modified" and "Accept-Ranges" backend response header lines; the bug had appeared in 0.7.44. Thanks to Maxim Dounin. *) Bugfix: the "[alert] zero size buf" error if subrequest returns an empty response; the bug had appeared in 0.8.5.

/*
 * 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

}