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Date:      Sat, 11 Jul 2015 16:28:13 +0000 (UTC)
From:      Mateusz Guzik <mjg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r285392 - head/sys/kern
Message-ID:  <201507111628.t6BGSDPp074635@repo.freebsd.org>
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Author: mjg
Date: Sat Jul 11 16:28:12 2015
New Revision: 285392
URL: https://svnweb.freebsd.org/changeset/base/285392

Log:
  vfs: move si_usecount manipulation to dedicated functions
  
  Reviewed by:	kib

Modified:
  head/sys/kern/vfs_subr.c

Modified: head/sys/kern/vfs_subr.c
==============================================================================
--- head/sys/kern/vfs_subr.c	Sat Jul 11 16:22:48 2015	(r285391)
+++ head/sys/kern/vfs_subr.c	Sat Jul 11 16:28:12 2015	(r285392)
@@ -105,6 +105,8 @@ static void	v_incr_usecount(struct vnode
 static void	v_decr_usecount(struct vnode *);
 static void	v_decr_useonly(struct vnode *);
 static void	v_upgrade_usecount(struct vnode *);
+static void	v_incr_devcount(struct vnode *);
+static void	v_decr_devcount(struct vnode *);
 static void	vnlru_free(int);
 static void	vgonel(struct vnode *);
 static void	vfs_knllock(void *arg);
@@ -2082,11 +2084,7 @@ v_incr_usecount(struct vnode *vp)
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 	vholdl(vp);
 	vp->v_usecount++;
-	if (vp->v_type == VCHR && vp->v_rdev != NULL) {
-		dev_lock();
-		vp->v_rdev->si_usecount++;
-		dev_unlock();
-	}
+	v_incr_devcount(vp);
 }
 
 /*
@@ -2099,11 +2097,7 @@ v_upgrade_usecount(struct vnode *vp)
 
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 	vp->v_usecount++;
-	if (vp->v_type == VCHR && vp->v_rdev != NULL) {
-		dev_lock();
-		vp->v_rdev->si_usecount++;
-		dev_unlock();
-	}
+	v_incr_devcount(vp);
 }
 
 /*
@@ -2120,11 +2114,7 @@ v_decr_usecount(struct vnode *vp)
 	    ("v_decr_usecount: negative usecount"));
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 	vp->v_usecount--;
-	if (vp->v_type == VCHR && vp->v_rdev != NULL) {
-		dev_lock();
-		vp->v_rdev->si_usecount--;
-		dev_unlock();
-	}
+	v_decr_devcount(vp);
 	vdropl(vp);
 }
 
@@ -2143,6 +2133,36 @@ v_decr_useonly(struct vnode *vp)
 	    ("v_decr_useonly: negative usecount"));
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 	vp->v_usecount--;
+	v_decr_devcount(vp);
+}
+
+/*
+ * Increment si_usecount of the associated device, if any.
+ */
+static void
+v_incr_devcount(struct vnode *vp)
+{
+
+#ifdef INVARIANTS
+	/* getnewvnode() calls v_incr_usecount() without holding interlock. */
+	if (vp->v_type != VNON || vp->v_data != NULL)
+		ASSERT_VI_LOCKED(vp, __FUNCTION__);
+#endif
+	if (vp->v_type == VCHR && vp->v_rdev != NULL) {
+		dev_lock();
+		vp->v_rdev->si_usecount++;
+		dev_unlock();
+	}
+}
+
+/*
+ * Decrement si_usecount of the associated device, if any.
+ */
+static void
+v_decr_devcount(struct vnode *vp)
+{
+
+	ASSERT_VI_LOCKED(vp, __FUNCTION__);
 	if (vp->v_type == VCHR && vp->v_rdev != NULL) {
 		dev_lock();
 		vp->v_rdev->si_usecount--;

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