- Remove GIANT_REQUIRED where giant is no longer required.

- Use VFS_LOCK_GIANT() rather than directly acquiring giant in places
   where giant is only held because vfs requires it.

Sponsored By:   Isilon Systems, Inc.

sys/vm/vm_fault.c

@@ -97,6 +97,8 @@ __FBSDID("$FreeBSD$");
 #include <vm/vnode_pager.h>
 #include <vm/vm_extern.h>
 
+#include <sys/mount.h>	/* XXX Temporary for VFS_LOCK_GIANT() */
+
 #define PFBAK 4
 #define PFFOR 4
 #define PAGEORDER_SIZE (PFBAK+PFFOR)
@@ -165,10 +167,12 @@ unlock_and_deallocate(struct faultstate *fs)
 	vm_object_deallocate(fs->first_object);
 	unlock_map(fs);	
 	if (fs->vp != NULL) { 
-		mtx_lock(&Giant);
+		int vfslocked;
+
+		vfslocked = VFS_LOCK_GIANT(fs->vp->v_mount);
 		vput(fs->vp);
-		mtx_unlock(&Giant);
 		fs->vp = NULL;
+		VFS_UNLOCK_GIANT(vfslocked);
 	}
 	if (!fs->map->system_map)
 		VM_UNLOCK_GIANT();

sys/vm/vm_mmap.c

@@ -1067,11 +1067,14 @@ vm_mmap_vnode(struct thread *td, vm_size_t objsize,
 	struct vattr va;
 	void *handle;
 	vm_object_t obj;
+	struct mount *mp;
 	int error, flags, type;
+	int vfslocked;
 
-	mtx_lock(&Giant);
+	mp = vp->v_mount;
+	vfslocked = VFS_LOCK_GIANT(mp);
 	if ((error = vget(vp, LK_EXCLUSIVE, td)) != 0) {
-		mtx_unlock(&Giant);
+		VFS_UNLOCK_GIANT(vfslocked);
 		return (error);
 	}
 	flags = *flagsp;
@@ -1157,7 +1160,7 @@ vm_mmap_vnode(struct thread *td, vm_size_t objsize,
 	*flagsp = flags;
 done:
 	vput(vp);
-	mtx_unlock(&Giant);
+	VFS_UNLOCK_GIANT(vfslocked);
 	return (error);
 }
 

sys/vm/vm_object.c

@@ -393,7 +393,7 @@ vm_object_vndeallocate(vm_object_t object)
 {
 	struct vnode *vp = (struct vnode *) object->handle;
 
-	GIANT_REQUIRED;
+	VFS_ASSERT_GIANT(vp->v_mount);
 	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 	KASSERT(object->type == OBJT_VNODE,
 	    ("vm_object_vndeallocate: not a vnode object"));
@@ -434,18 +434,22 @@ vm_object_deallocate(vm_object_t object)
 	vm_object_t temp;
 
 	while (object != NULL) {
+		int vfslocked;
 		/*
 		 * In general, the object should be locked when working with
 		 * its type.  In this case, in order to maintain proper lock
 		 * ordering, an exception is possible because a vnode-backed
 		 * object never changes its type.
 		 */
-		if (object->type == OBJT_VNODE)
+		vfslocked = 0;
-			mtx_lock(&Giant);
+		if (object->type == OBJT_VNODE) {
+			struct vnode *vp = (struct vnode *) object->handle;
+			vfslocked = VFS_LOCK_GIANT(vp->v_mount);
+		}
 		VM_OBJECT_LOCK(object);
 		if (object->type == OBJT_VNODE) {
 			vm_object_vndeallocate(object);
-			mtx_unlock(&Giant);
+			VFS_UNLOCK_GIANT(vfslocked);
 			return;
 		}
 
@@ -671,7 +675,6 @@ vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int
 	int pagerflags;
 	int curgeneration;
 
-	GIANT_REQUIRED;
 	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 	if (object->type != OBJT_VNODE ||
 		(object->flags & OBJ_MIGHTBEDIRTY) == 0)
@@ -1000,9 +1003,10 @@ vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
 	 */
 	if (object->type == OBJT_VNODE &&
 	    (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
+		int vfslocked;
 		vp = object->handle;
 		VM_OBJECT_UNLOCK(object);
-		mtx_lock(&Giant);
+		vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, curthread);
 		flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
 		flags |= invalidate ? OBJPC_INVAL : 0;
@@ -1013,7 +1017,7 @@ vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
 		    flags);
 		VM_OBJECT_UNLOCK(object);
 		VOP_UNLOCK(vp, 0, curthread);
-		mtx_unlock(&Giant);
+		VFS_UNLOCK_GIANT(vfslocked);
 		VM_OBJECT_LOCK(object);
 	}
 	if ((object->type == OBJT_VNODE ||

sys/vm/vnode_pager.c

@@ -215,6 +215,7 @@ vnode_pager_haspage(object, pindex, before, after)
 	int poff;
 	int bsize;
 	int pagesperblock, blocksperpage;
+	int vfslocked;
 
 	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 	/*
@@ -248,9 +249,9 @@ vnode_pager_haspage(object, pindex, before, after)
 		reqblock = pindex * blocksperpage;
 	}
 	VM_OBJECT_UNLOCK(object);
-	mtx_lock(&Giant);
+	vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 	err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
-	mtx_unlock(&Giant);
+	VFS_UNLOCK_GIANT(vfslocked);
 	VM_OBJECT_LOCK(object);
 	if (err)
 		return TRUE;
@@ -397,7 +398,6 @@ vnode_pager_addr(vp, address, run)
 	daddr_t vblock;
 	int voffset;
 
-	GIANT_REQUIRED;
 	if (address < 0)
 		return -1;
 
@@ -441,8 +441,6 @@ vnode_pager_input_smlfs(object, m)
 	vm_offset_t bsize;
 	int error = 0;
 
-	GIANT_REQUIRED;
-
 	vp = object->handle;
 	if (vp->v_mount == NULL)
 		return VM_PAGER_BAD;
@@ -619,14 +617,15 @@ vnode_pager_getpages(object, m, count, reqpage)
 	int rtval;
 	struct vnode *vp;
 	int bytes = count * PAGE_SIZE;
+	int vfslocked;
 
 	vp = object->handle;
 	VM_OBJECT_UNLOCK(object);
-	mtx_lock(&Giant);
+	vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 	rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0);
 	KASSERT(rtval != EOPNOTSUPP,
 	    ("vnode_pager: FS getpages not implemented\n"));
-	mtx_unlock(&Giant);
+	VFS_UNLOCK_GIANT(vfslocked);
 	VM_OBJECT_LOCK(object);
 	return rtval;
 }
@@ -653,7 +652,6 @@ vnode_pager_generic_getpages(vp, m, bytecount, reqpage)
 	int count;
 	int error = 0;
 
-	GIANT_REQUIRED;
 	object = vp->v_object;
 	count = bytecount / PAGE_SIZE;
 
@@ -946,7 +944,6 @@ vnode_pager_putpages(object, m, count, sync, rtvals)
 	struct mount *mp;
 	int bytes = count * PAGE_SIZE;
 
-	GIANT_REQUIRED;
 	/*
 	 * Force synchronous operation if we are extremely low on memory
 	 * to prevent a low-memory deadlock.  VOP operations often need to
@@ -1006,7 +1003,6 @@ vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals)
 	int error;
 	int ioflags;
 
-	GIANT_REQUIRED;
 	object = vp->v_object;
 	count = bytecount / PAGE_SIZE;