From: Dan Mick <dan.mick@redhat.com>
Date: Fri, 4 Aug 2017 01:22:47 +0000 (-0700)
Subject: common/buffer: off-by-one error in max iov length blocking
X-Git-Tag: v12.1.3~89^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=89f85d22c1f9eee34ee5a36f8071137023a56f06;p=ceph.git

common/buffer: off-by-one error in max iov length blocking

The loop in write_fd stops at IOV_MAX-1; it could go to IOV_MAX
and write in more-natural sizes without extra tail writes.

Fixes: http://tracker.ceph.com/issues/20907
Signed-off-by: Dan Mick <dan.mick@redhat.com>
---

diff --git a/src/common/buffer.cc b/src/common/buffer.cc
index 4b75b9b63179..b8e87d1eea3d 100644
--- a/src/common/buffer.cc
+++ b/src/common/buffer.cc
@@ -2382,7 +2382,7 @@ int buffer::list::write_fd(int fd) const
     }
     ++p;
 
-    if (iovlen == IOV_MAX-1 ||
+    if (iovlen == IOV_MAX ||
 	p == _buffers.end()) {
       iovec *start = iov;
       int num = iovlen;