export aio presence knowledge to prevent using "aio sendfile",
if aio does not present

src/http/ngx_http_copy_filter_module.c

diff --git a/src/http/ngx_http_copy_filter_module.c b/src/http/ngx_http_copy_filter_module.c
index 3c4c288..a1b616a 100644
--- a/src/http/ngx_http_copy_filter_module.c
+++ b/src/http/ngx_http_copy_filter_module.c
@@ -118,7 +118,7 @@
         ctx->filter_ctx = r;
 
 #if (NGX_HAVE_FILE_AIO)
-        if (clcf->aio) {
+        if (ngx_file_aio && clcf->aio) {
             ctx->aio_handler = ngx_http_copy_aio_handler;
 #if (NGX_HAVE_AIO_SENDFILE)
             c->aio_sendfile = (clcf->aio == NGX_HTTP_AIO_SENDFILE);

src/http/ngx_http_file_cache.c

diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
index 0a9b761..431b1e5 100644
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -12,6 +12,8 @@
 
 static ngx_int_t ngx_http_file_cache_read(ngx_http_request_t *r,
     ngx_http_cache_t *c);
+static ssize_t ngx_http_file_cache_aio_read(ngx_http_request_t *r,
+    ngx_http_cache_t *c);
 #if (NGX_HAVE_FILE_AIO)
 static void ngx_http_cache_aio_event_handler(ngx_event_t *ev);
 #endif
@@ -330,36 +332,9 @@
 
     c = r->cache;
 
-#if (NGX_HAVE_FILE_AIO)
-    {
-    ngx_http_core_loc_conf_t      *clcf;
+    n = ngx_http_file_cache_aio_read(r, c);
 
-    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
-
-    if (clcf->aio) {
-        n = ngx_file_aio_read(&c->file, c->buf->pos, c->body_start, 0, r->pool);
-
-        if (n == NGX_AGAIN) {
-            c->file.aio->data = r;
-            c->file.aio->handler = ngx_http_cache_aio_event_handler;
-
-            r->main->blocked++;
-            r->aio = 1;
-
-            return NGX_AGAIN;
-        }
-
-    } else {
-        n = ngx_read_file(&c->file, c->buf->pos, c->body_start, 0);
-    }
-    }
-#else
-
-    n = ngx_read_file(&c->file, c->buf->pos, c->body_start, 0);
-
-#endif
-
-    if (n == NGX_ERROR) {
+    if (n < 0) {
         return n;
     }
 
@@ -432,8 +407,46 @@
 }
 
 
+static ssize_t
+ngx_http_file_cache_aio_read(ngx_http_request_t *r, ngx_http_cache_t *c)
+{
 #if (NGX_HAVE_FILE_AIO)
+    ssize_t                    n;
+    ngx_http_core_loc_conf_t  *clcf;
 
+    if (!ngx_file_aio) {
+        goto noaio;
+    }
+
+    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+
+    if (!clcf->aio) {
+        goto noaio;
+    }
+
+    n = ngx_file_aio_read(&c->file, c->buf->pos, c->body_start, 0, r->pool);
+
+    if (n != NGX_AGAIN) {
+        return n;
+    }
+
+    c->file.aio->data = r;
+    c->file.aio->handler = ngx_http_cache_aio_event_handler;
+
+    r->main->blocked++;
+    r->aio = 1;
+
+    return NGX_AGAIN;
+
+noaio:
+
+#endif
+
+    return ngx_read_file(&c->file, c->buf->pos, c->body_start, 0);
+}
+
+
+#if (NGX_HAVE_FILE_AIO)
 
 static void
 ngx_http_cache_aio_event_handler(ngx_event_t *ev)

src/os/unix/ngx_file_aio_read.c

diff --git a/src/os/unix/ngx_file_aio_read.c b/src/os/unix/ngx_file_aio_read.c
index 19a7589..ef7a461 100644
--- a/src/os/unix/ngx_file_aio_read.c
+++ b/src/os/unix/ngx_file_aio_read.c
@@ -39,12 +39,11 @@
 ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset,
     ngx_pool_t *pool)
 {
-    int                 n;
-    ngx_event_t        *ev;
-    ngx_event_aio_t    *aio;
-    static ngx_uint_t   enosys = 0;
+    int               n;
+    ngx_event_t      *ev;
+    ngx_event_aio_t  *aio;
 
-    if (enosys) {
+    if (!ngx_file_aio) {
         return ngx_read_file(file, buf, size, offset);
     }
 
@@ -116,7 +115,7 @@
                       "aio_read(\"%V\") failed", &file->name);
 
         if (n == NGX_ENOSYS) {
-            enosys = 1;
+            ngx_file_aio = 0;
             return ngx_read_file(file, buf, size, offset);
         }
 

src/os/unix/ngx_files.c

diff --git a/src/os/unix/ngx_files.c b/src/os/unix/ngx_files.c
index 618d4e2..2264cc1 100644
--- a/src/os/unix/ngx_files.c
+++ b/src/os/unix/ngx_files.c
@@ -8,6 +8,13 @@
 #include <ngx_core.h>
 
 
+#if (NGX_HAVE_FILE_AIO)
+
+ngx_uint_t  ngx_file_aio = 1;
+
+#endif
+
+
 ssize_t
 ngx_read_file(ngx_file_t *file, u_char *buf, size_t size, off_t offset)
 {

src/os/unix/ngx_files.h

diff --git a/src/os/unix/ngx_files.h b/src/os/unix/ngx_files.h
index 9662621..2efd247 100644
--- a/src/os/unix/ngx_files.h
+++ b/src/os/unix/ngx_files.h
@@ -313,6 +313,8 @@
 ssize_t ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size,
     off_t offset, ngx_pool_t *pool);
 
+extern ngx_uint_t  ngx_file_aio;
+
 #endif
 
 

src/os/unix/ngx_linux_aio_read.c

diff --git a/src/os/unix/ngx_linux_aio_read.c b/src/os/unix/ngx_linux_aio_read.c
index 3b4185c..834a11d 100644
--- a/src/os/unix/ngx_linux_aio_read.c
+++ b/src/os/unix/ngx_linux_aio_read.c
@@ -27,13 +27,12 @@
 ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset,
     ngx_pool_t *pool)
 {
-    long                n;
-    struct iocb        *piocb[1];
-    ngx_event_t        *ev;
-    ngx_event_aio_t    *aio;
-    static ngx_uint_t   enosys = 0;
+    long              n;
+    struct iocb      *piocb[1];
+    ngx_event_t      *ev;
+    ngx_event_aio_t  *aio;
 
-    if (enosys) {
+    if (!ngx_file_aio) {
         return ngx_read_file(file, buf, size, offset);
     }
 
@@ -109,7 +108,7 @@
                   "io_submit(\"%V\") failed", &file->name);
 
     if (n == NGX_ENOSYS) {
-        enosys = 1;
+        ngx_file_aio = 0;
         return ngx_read_file(file, buf, size, offset);
     }