IOV_MAX handling microoptimization.

We now stop on IOV_MAX iovec entries only if we are going to add new one,
i.e. next buffer can't be coalesced into last iovec.

This also fixes incorrect checks for trailer creation on FreeBSD and
Mac OS X, header.nelts was checked instead of trailer.nelts.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/os/unix/ngx_writev_chain.c b/src/os/unix/ngx_writev_chain.c
index a752b1f91..805982d65 100644
--- a/src/os/unix/ngx_writev_chain.c
+++ b/src/os/unix/ngx_writev_chain.c
@@ -71,8 +71,8 @@ ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
 
         /* create the iovec and coalesce the neighbouring bufs */
 
-        for (cl = in; cl && vec.nelts < IOV_MAX && send < limit; cl = cl->next)
-        {
+        for (cl = in; cl && send < limit; cl = cl->next) {
+
             if (ngx_buf_special(cl->buf)) {
                 continue;
             }
@@ -93,6 +93,10 @@ ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                 iov->iov_len += size;
 
             } else {
+                if (vec.nelts >= IOV_MAX) {
+                    break;
+                }
+
                 iov = ngx_array_push(&vec);
                 if (iov == NULL) {
                     return NGX_CHAIN_ERROR;