Author: attilio
Date: Sun Nov 22 16:09:27 2009
New Revision: 199652
URL: http://svn.freebsd.org/changeset/base/199652
Log:
MFC r199007:
Fix a memory leak.
Modified:
stable/8/sys/fs/fifofs/fifo_vnops.c
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/amd64/include/xen/ (props changed)
stable/8/sys/cddl/contrib/opensolaris/ (props changed)
stable/8/sys/contrib/dev/acpica/ (props changed)
stable/8/sys/contrib/pf/ (props changed)
stable/8/sys/dev/xen/xenpci/ (props changed)
Modified: stable/8/sys/fs/fifofs/fifo_vnops.c
==============================================================================
--- stable/8/sys/fs/fifofs/fifo_vnops.c Sun Nov 22 16:04:49 2009
(r199651)
+++ stable/8/sys/fs/fifofs/fifo_vnops.c Sun Nov 22 16:09:27 2009
(r199652)
@@ -78,6 +78,10 @@ struct fileops fifo_ops_f = {
/*
* This structure is associated with the FIFO vnode and stores
* the state associated with the FIFO.
+ * Notes about locking:
+ * - fi_readsock and fi_writesock are invariant since init time.
+ * - fi_readers and fi_writers are vnode lock protected.
+ * - fi_wgen is fif_mtx lock protected.
*/
struct fifoinfo {
struct socket *fi_readsock;
@@ -215,14 +219,9 @@ fail1:
}
/*
- * General access to fi_readers and fi_writers is protected using
- * the vnode lock.
- *
- * Protect the increment of fi_readers and fi_writers and the
- * associated calls to wakeup() with the fifo mutex in addition
- * to the vnode lock. This allows the vnode lock to be dropped
- * for the msleep() calls below, and using the fifo mutex with
- * msleep() prevents the wakeup from being missed.
+ * Use the fifo_mtx lock here, in addition to the vnode lock,
+ * in order to allow vnode lock dropping before msleep() calls
+ * and still avoiding missed wakeups.
*/
mtx_lock(&fifo_mtx);
if (ap->a_mode & FREAD) {
@@ -241,6 +240,8 @@ fail1:
if (ap->a_mode & FWRITE) {
if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
mtx_unlock(&fifo_mtx);
+ if (fip->fi_writers == 0)
+ fifo_cleanup(vp);
return (ENXIO);
}
fip->fi_writers++;
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