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.

5 files changed, 44 insertions, 18 deletions

diff --git a/src/os/unix/ngx_darwin_sendfile_chain.c b/src/os/unix/ngx_darwin_sendfile_chain.c
index ec247d21b..078d10b24 100644
--- a/src/os/unix/ngx_darwin_sendfile_chain.c
+++ b/src/os/unix/ngx_darwin_sendfile_chain.c
@@ -103,10 +103,8 @@ ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
         prev = NULL;
         iov = NULL;
 
-        for (cl = in;
-             cl && header.nelts < IOV_MAX && send < limit;
-             cl = cl->next)
-        {
+        for (cl = in; cl && send < limit; cl = cl->next) {
+
             if (ngx_buf_special(cl->buf)) {
                 continue;
             }
@@ -125,6 +123,10 @@ ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                 iov->iov_len += (size_t) size;
 
             } else {
+                if (header.nelts >= IOV_MAX) {
+                    break;
+                }
+
                 iov = ngx_array_push(&header);
                 if (iov == NULL) {
                     return NGX_CHAIN_ERROR;
@@ -178,7 +180,7 @@ ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
             prev = NULL;
             iov = NULL;
 
-            while (cl && header.nelts < IOV_MAX && send < limit) {
+            while (cl && send < limit) {
 
                 if (ngx_buf_special(cl->buf)) {
                     cl = cl->next;
@@ -199,6 +201,10 @@ ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                     iov->iov_len += (size_t) size;
 
                 } else {
+                    if (trailer.nelts >= IOV_MAX) {
+                        break;
+                    }
+
                     iov = ngx_array_push(&trailer);
                     if (iov == NULL) {
                         return NGX_CHAIN_ERROR;
diff --git a/src/os/unix/ngx_freebsd_sendfile_chain.c b/src/os/unix/ngx_freebsd_sendfile_chain.c
index 724bb0d70..f58b5c20f 100644
--- a/src/os/unix/ngx_freebsd_sendfile_chain.c
+++ b/src/os/unix/ngx_freebsd_sendfile_chain.c
@@ -107,10 +107,8 @@ ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
         prev = NULL;
         iov = NULL;
 
-        for (cl = in;
-             cl && header.nelts < IOV_MAX && send < limit;
-             cl = cl->next)
-        {
+        for (cl = in; cl && send < limit; cl = cl->next) {
+
             if (ngx_buf_special(cl->buf)) {
                 continue;
             }
@@ -129,6 +127,10 @@ ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                 iov->iov_len += (size_t) size;
 
             } else {
+                if (header.nelts >= IOV_MAX){
+                    break;
+                }
+
                 iov = ngx_array_push(&header);
                 if (iov == NULL) {
                     return NGX_CHAIN_ERROR;
@@ -183,7 +185,7 @@ ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
             prev = NULL;
             iov = NULL;
 
-            while (cl && header.nelts < IOV_MAX && send < limit) {
+            while (cl && send < limit) {
 
                 if (ngx_buf_special(cl->buf)) {
                     cl = cl->next;
@@ -204,6 +206,10 @@ ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                     iov->iov_len += (size_t) size;
 
                 } else {
+                    if (trailer.nelts >= IOV_MAX){
+                        break;
+                    }
+
                     iov = ngx_array_push(&trailer);
                     if (iov == NULL) {
                         return NGX_CHAIN_ERROR;
diff --git a/src/os/unix/ngx_linux_sendfile_chain.c b/src/os/unix/ngx_linux_sendfile_chain.c
index 4f6fdf587..e8f3d5a89 100644
--- a/src/os/unix/ngx_linux_sendfile_chain.c
+++ b/src/os/unix/ngx_linux_sendfile_chain.c
@@ -89,10 +89,8 @@ ngx_linux_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
 
         /* create the iovec and coalesce the neighbouring bufs */
 
-        for (cl = in;
-             cl && header.nelts < IOV_MAX && send < limit;
-             cl = cl->next)
-        {
+        for (cl = in; cl && send < limit; cl = cl->next) {
+
             if (ngx_buf_special(cl->buf)) {
                 continue;
             }
@@ -132,6 +130,10 @@ ngx_linux_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                 iov->iov_len += (size_t) size;
 
             } else {
+                if (header.nelts >= IOV_MAX) {
+                    break;
+                }
+
                 iov = ngx_array_push(&header);
                 if (iov == NULL) {
                     return NGX_CHAIN_ERROR;
diff --git a/src/os/unix/ngx_solaris_sendfilev_chain.c b/src/os/unix/ngx_solaris_sendfilev_chain.c
index 64e59aa2e..f800c15f5 100644
--- a/src/os/unix/ngx_solaris_sendfilev_chain.c
+++ b/src/os/unix/ngx_solaris_sendfilev_chain.c
@@ -94,8 +94,8 @@ ngx_solaris_sendfilev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
 
         /* create the sendfilevec 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;
             }
@@ -113,6 +113,10 @@ ngx_solaris_sendfilev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                     sfv->sfv_len += (size_t) size;
 
                 } else {
+                    if (vec.nelts >= IOV_MAX) {
+                        break;
+                    }
+
                     sfv = ngx_array_push(&vec);
                     if (sfv == NULL) {
                         return NGX_CHAIN_ERROR;
@@ -147,6 +151,10 @@ ngx_solaris_sendfilev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                     sfv->sfv_len += (size_t) size;
 
                 } else {
+                    if (vec.nelts >= IOV_MAX) {
+                        break;
+                    }
+
                     sfv = ngx_array_push(&vec);
                     if (sfv == NULL) {
                         return NGX_CHAIN_ERROR;
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;