From: Simon Schubert <corecode@dragonflybsd.org>
Date: Tue, 21 Jul 2009 23:21:44 +0000 (+0200)
Subject: dma: don't block when trying to aquire a queue file
X-Git-Tag: v2.4.0~402^2~2
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/b95bffd0bae1f4dcf763f209ee67c294646b73ae

dma: don't block when trying to aquire a queue file

We might race with some other process, so it is imperative to treat a
locked file as a soft error instead of blocking on the file until the
other process unlocks it.
---

diff --git a/libexec/dma/spool.c b/libexec/dma/spool.c
index d9d17e2839..9a74620220 100644
--- a/libexec/dma/spool.c
+++ b/libexec/dma/spool.c
@@ -308,7 +308,7 @@ aquirespool(struct qitem *it)
 	int queuefd;
 
 	if (it->queuef == NULL) {
-		queuefd = open_locked(it->queuefn, O_RDWR);
+		queuefd = open_locked(it->queuefn, O_RDWR|O_NONBLOCK);
 		if (queuefd < 0)
 			goto fail;
 		it->queuef = fdopen(queuefd, "r+");