Author: mjg
Date: Sun Jan 5 01:00:11 2020
New Revision: 356364
URL: https://svnweb.freebsd.org/changeset/base/356364
Log:
vfs: factor out avoidable branches in _vn_lock
Modified:
head/sys/kern/vfs_vnops.c
Modified: head/sys/kern/vfs_vnops.c
==============================================================================
--- head/sys/kern/vfs_vnops.c Sun Jan 5 00:59:47 2020 (r356363)
+++ head/sys/kern/vfs_vnops.c Sun Jan 5 01:00:11 2020 (r356364)
@@ -1564,28 +1564,53 @@ vn_poll(struct file *fp, int events, struct ucred *act
* Acquire the requested lock and then check for validity. LK_RETRY
* permits vn_lock to return doomed vnodes.
*/
-int
-_vn_lock(struct vnode *vp, int flags, char *file, int line)
+static int __noinline
+_vn_lock_fallback(struct vnode *vp, int flags, char *file, int line, int error)
{
- int error;
- VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
- ("vn_lock: no locktype"));
- VNASSERT(vp->v_holdcnt != 0, vp, ("vn_lock: zero hold count"));
-retry:
- error = VOP_LOCK1(vp, flags, file, line);
- flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */
KASSERT((flags & LK_RETRY) == 0 || error == 0,
("vn_lock: error %d incompatible with flags %#x", error, flags));
+ if (error == 0)
+ VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed"));
+
if ((flags & LK_RETRY) == 0) {
- if (error == 0 && VN_IS_DOOMED(vp)) {
+ if (error == 0) {
VOP_UNLOCK(vp);
error = ENOENT;
}
- } else if (error != 0)
- goto retry;
- return (error);
+ return (error);
+ }
+
+ /*
+ * LK_RETRY case.
+ *
+ * Nothing to do if we got the lock.
+ */
+ if (error == 0)
+ return (0);
+
+ /*
+ * Interlock was dropped by the call in _vn_lock.
+ */
+ flags &= ~LK_INTERLOCK;
+ do {
+ error = VOP_LOCK1(vp, flags, file, line);
+ } while (error != 0);
+ return (0);
+}
+
+int
+_vn_lock(struct vnode *vp, int flags, char *file, int line)
+{
+ int error;
+
+ VNASSERT((flags & LK_TYPE_MASK) != 0, vp, ("vn_lock: no locktype"));
+ VNASSERT(vp->v_holdcnt != 0, vp, ("vn_lock: zero hold count"));
+ error = VOP_LOCK1(vp, flags, file, line);
+ if (__predict_false(error != 0 || VN_IS_DOOMED(vp)))
+ return (_vn_lock_fallback(vp, flags, file, line, error));
+ return (0);
}
/*
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