From owner-svn-src-head@FreeBSD.ORG  Mon Nov  3 07:46:52 2014
Return-Path: <owner-svn-src-head@FreeBSD.ORG>
Delivered-To: svn-src-head@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 1B79BDC;
 Mon,  3 Nov 2014 07:46:52 +0000 (UTC)
Received: from svn.freebsd.org (svn.freebsd.org
 [IPv6:2001:1900:2254:2068::e6a:0])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 07FB27AE;
 Mon,  3 Nov 2014 07:46:52 +0000 (UTC)
Received: from svn.freebsd.org ([127.0.1.70])
 by svn.freebsd.org (8.14.9/8.14.9) with ESMTP id sA37kpO0037114;
 Mon, 3 Nov 2014 07:46:51 GMT (envelope-from mjg@FreeBSD.org)
Received: (from mjg@localhost)
 by svn.freebsd.org (8.14.9/8.14.9/Submit) id sA37kpPu037113;
 Mon, 3 Nov 2014 07:46:51 GMT (envelope-from mjg@FreeBSD.org)
Message-Id: <201411030746.sA37kpPu037113@svn.freebsd.org>
X-Authentication-Warning: svn.freebsd.org: mjg set sender to mjg@FreeBSD.org
 using -f
From: Mateusz Guzik <mjg@FreeBSD.org>
Date: Mon, 3 Nov 2014 07:46:51 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r274017 - head/sys/kern
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 03 Nov 2014 07:46:52 -0000

Author: mjg
Date: Mon Nov  3 07:46:51 2014
New Revision: 274017
URL: https://svnweb.freebsd.org/changeset/base/274017

Log:
  Provide an on-stack temporary buffer for small ioctl requests.

Modified:
  head/sys/kern/sys_generic.c

Modified: head/sys/kern/sys_generic.c
==============================================================================
--- head/sys/kern/sys_generic.c	Mon Nov  3 07:18:42 2014	(r274016)
+++ head/sys/kern/sys_generic.c	Mon Nov  3 07:46:51 2014	(r274017)
@@ -649,6 +649,7 @@ sys_ioctl(struct thread *td, struct ioct
 	u_long com;
 	int arg, error;
 	u_int size;
+	u_char smalldata[128];
 	caddr_t data;
 
 	if (uap->com > 0xffffffff) {
@@ -680,17 +681,18 @@ sys_ioctl(struct thread *td, struct ioct
 			arg = (intptr_t)uap->data;
 			data = (void *)&arg;
 			size = 0;
-		} else
-			data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
+		} else {
+			if (size <= sizeof(smalldata))
+				data = smalldata;
+			else
+				data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
+		}
 	} else
 		data = (void *)&uap->data;
 	if (com & IOC_IN) {
 		error = copyin(uap->data, data, (u_int)size);
-		if (error) {
-			if (size > 0)
-				free(data, M_IOCTLOPS);
-			return (error);
-		}
+		if (error != 0)
+			goto out;
 	} else if (com & IOC_OUT) {
 		/*
 		 * Zero the buffer so the user always
@@ -704,7 +706,8 @@ sys_ioctl(struct thread *td, struct ioct
 	if (error == 0 && (com & IOC_OUT))
 		error = copyout(data, uap->data, (u_int)size);
 
-	if (size > 0)
+out:
+	if (size > 0 && data != (caddr_t)&smalldata)
 		free(data, M_IOCTLOPS);
 	return (error);
 }