From owner-svn-src-all@FreeBSD.ORG  Mon Jun 11 22:05:26 2012
Return-Path: <owner-svn-src-all@FreeBSD.ORG>
Delivered-To: svn-src-all@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id E6CD11065679;
	Mon, 11 Jun 2012 22:05:26 +0000 (UTC) (envelope-from pjd@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c])
	by mx1.freebsd.org (Postfix) with ESMTP id B9AAE8FC12;
	Mon, 11 Jun 2012 22:05:26 +0000 (UTC)
Received: from svn.freebsd.org (localhost [127.0.0.1])
	by svn.freebsd.org (8.14.4/8.14.4) with ESMTP id q5BM5QIZ013268;
	Mon, 11 Jun 2012 22:05:26 GMT (envelope-from pjd@svn.freebsd.org)
Received: (from pjd@localhost)
	by svn.freebsd.org (8.14.4/8.14.4/Submit) id q5BM5QIv013266;
	Mon, 11 Jun 2012 22:05:26 GMT (envelope-from pjd@svn.freebsd.org)
Message-Id: <201206112205.q5BM5QIv013266@svn.freebsd.org>
From: Pawel Jakub Dawidek <pjd@FreeBSD.org>
Date: Mon, 11 Jun 2012 22:05:26 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
	svn-src-head@freebsd.org
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cc: 
Subject: svn commit: r236935 - head/sys/kern
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
	user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 11 Jun 2012 22:05:27 -0000

Author: pjd
Date: Mon Jun 11 22:05:26 2012
New Revision: 236935
URL: http://svn.freebsd.org/changeset/base/236935

Log:
  fdgrowtable() no longer drops the filedesc lock so it is enough to
  retry finding free file descriptor only once after fdgrowtable().
  
  Spotted by:	pluknet
  MFC after:	1 month

Modified:
  head/sys/kern/kern_descrip.c

Modified: head/sys/kern/kern_descrip.c
==============================================================================
--- head/sys/kern/kern_descrip.c	Mon Jun 11 21:56:37 2012	(r236934)
+++ head/sys/kern/kern_descrip.c	Mon Jun 11 22:05:26 2012	(r236935)
@@ -1478,29 +1478,33 @@ fdalloc(struct thread *td, int minfd, in
 	/*
 	 * Search the bitmap for a free descriptor.  If none is found, try
 	 * to grow the file table.  Keep at it until we either get a file
-	 * descriptor or run into process or system limits; fdgrowtable()
-	 * may drop the filedesc lock, so we're in a race.
+	 * descriptor or run into process or system limits.
 	 */
-	for (;;) {
-		fd = fd_first_free(fdp, minfd, fdp->fd_nfiles);
-		if (fd >= maxfd)
-			return (EMFILE);
-		if (fd < fdp->fd_nfiles)
-			break;
+	fd = fd_first_free(fdp, minfd, fdp->fd_nfiles);
+	if (fd >= maxfd)
+		return (EMFILE);
+	if (fd >= fdp->fd_nfiles) {
 #ifdef RACCT
 		PROC_LOCK(p);
-		error = racct_set(p, RACCT_NOFILE, min(fdp->fd_nfiles * 2, maxfd));
+		error = racct_set(p, RACCT_NOFILE,
+		    min(fdp->fd_nfiles * 2, maxfd));
 		PROC_UNLOCK(p);
 		if (error != 0)
 			return (EMFILE);
 #endif
 		fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd));
+		/* Retry... */
+		fd = fd_first_free(fdp, minfd, fdp->fd_nfiles);
+		if (fd >= maxfd)
+			return (EMFILE);
 	}
 
 	/*
 	 * Perform some sanity checks, then mark the file descriptor as
 	 * used and return it to the caller.
 	 */
+	KASSERT((unsigned int)fd < min(maxfd, fdp->fd_nfiles),
+	    ("invalid descriptor %d", fd));
 	KASSERT(!fdisused(fdp, fd),
 	    ("fd_first_free() returned non-free descriptor"));
 	KASSERT(fdp->fd_ofiles[fd] == NULL, ("file descriptor isn't free"));