# HG changeset patch
# User Maxim Dounin <mdounin@mdounin.ru>
# Date 1635528111 -10800
# Node ID a2613fc1bce5f1dd87c1baabb20f450174e87197
# Parent  51a260276425b4e7c1302d0a8b0f25ba4d9becfb
Fixed sendfile() limit handling on Linux.

On Linux starting with 2.6.16, sendfile() silently limits all operations
to MAX_RW_COUNT, defined as (INT_MAX & PAGE_MASK).  This incorrectly
triggered the interrupt check, and resulted in 0-sized writev() on the
next loop iteration.

Fix is to make sure the limit is always checked, so we will return from
the loop if the limit is already reached even if number of bytes sent is
not exactly equal to the number of bytes we've tried to send.

diff --git a/src/os/unix/ngx_linux_sendfile_chain.c b/src/os/unix/ngx_linux_sendfile_chain.c
--- a/src/os/unix/ngx_linux_sendfile_chain.c
+++ b/src/os/unix/ngx_linux_sendfile_chain.c
@@ -38,6 +38,9 @@ static void ngx_linux_sendfile_thread_ha
  * On Linux up to 2.6.16 sendfile() does not allow to pass the count parameter
  * more than 2G-1 bytes even on 64-bit platforms: it returns EINVAL,
  * so we limit it to 2G-1 bytes.
+ *
+ * On Linux 2.6.16 and later, sendfile() silently limits the count parameter
+ * to 2G minus the page size, even on 64-bit platforms.
  */
 
 #define NGX_SENDFILE_MAXSIZE  2147483647L
@@ -216,7 +219,6 @@ ngx_linux_sendfile_chain(ngx_connection_
              */
 
             send = prev_send + sent;
-            continue;
         }
 
         if (send >= limit || in == NULL) {