Merge tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core and debugfs updates from Greg KH:
 "Here is the big set of driver core and debugfs updates for 6.14-rc1.

  Included in here is a bunch of driver core, PCI, OF, and platform rust
  bindings (all acked by the different subsystem maintainers), hence the
  merge conflict with the rust tree, and some driver core api updates to
  mark things as const, which will also require some fixups due to new
  stuff coming in through other trees in this merge window.

  There are also a bunch of debugfs updates from Al, and there is at
  least one user that does have a regression with these, but Al is
  working on tracking down the fix for it. In my use (and everyone
  else's linux-next use), it does not seem like a big issue at the
  moment.

  Here's a short list of the things in here:

   - driver core rust bindings for PCI, platform, OF, and some i/o
     functions.

     We are almost at the "write a real driver in rust" stage now,
     depending on what you want to do.

   - misc device rust bindings and a sample driver to show how to use
     them

   - debugfs cleanups in the fs as well as the users of the fs api for
     places where drivers got it wrong or were unnecessarily doing
     things in complex ways.

   - driver core const work, making more of the api take const * for
     different parameters to make the rust bindings easier overall.

   - other small fixes and updates

  All of these have been in linux-next with all of the aforementioned
  merge conflicts, and the one debugfs issue, which looks to be resolved
  "soon""

* tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits)
  rust: device: Use as_char_ptr() to avoid explicit cast
  rust: device: Replace CString with CStr in property_present()
  devcoredump: Constify 'struct bin_attribute'
  devcoredump: Define 'struct bin_attribute' through macro
  rust: device: Add property_present()
  saner replacement for debugfs_rename()
  orangefs-debugfs: don't mess with ->d_name
  octeontx2: don't mess with ->d_parent or ->d_parent->d_name
  arm_scmi: don't mess with ->d_parent->d_name
  slub: don't mess with ->d_name
  sof-client-ipc-flood-test: don't mess with ->d_name
  qat: don't mess with ->d_name
  xhci: don't mess with ->d_iname
  mtu3: don't mess wiht ->d_iname
  greybus/camera - stop messing with ->d_iname
  mediatek: stop messing with ->d_iname
  netdevsim: don't embed file_operations into your structs
  b43legacy: make use of debugfs_get_aux()
  b43: stop embedding struct file_operations into their objects
  carl9170: stop embedding file_operations into their objects
  ...

5 files changed, 223 insertions, 218 deletions

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 16e198a26339..e33cc77699cd 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -47,11 +47,17 @@ const struct file_operations debugfs_noop_file_operations = {
 
 #define F_DENTRY(filp) ((filp)->f_path.dentry)
 
+const void *debugfs_get_aux(const struct file *file)
+{
+	return DEBUGFS_I(file_inode(file))->aux;
+}
+EXPORT_SYMBOL_GPL(debugfs_get_aux);
+
 const struct file_operations *debugfs_real_fops(const struct file *filp)
 {
 	struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;
 
-	if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) {
+	if (!fsd) {
 		/*
 		 * Urgh, we've been called w/o a protecting
 		 * debugfs_file_get().
@@ -84,9 +90,11 @@ static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode)
 		return -EINVAL;
 
 	d_fsd = READ_ONCE(dentry->d_fsdata);
-	if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) {
+	if (d_fsd) {
 		fsd = d_fsd;
 	} else {
+		struct inode *inode = dentry->d_inode;
+
 		if (WARN_ON(mode == DBGFS_GET_ALREADY))
 			return -EINVAL;
 
@@ -95,23 +103,38 @@ static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode)
 			return -ENOMEM;
 
 		if (mode == DBGFS_GET_SHORT) {
-			fsd->real_fops = NULL;
-			fsd->short_fops = (void *)((unsigned long)d_fsd &
-						~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
+			const struct debugfs_short_fops *ops;
+			ops = fsd->short_fops = DEBUGFS_I(inode)->short_fops;
+			if (ops->llseek)
+				fsd->methods |= HAS_LSEEK;
+			if (ops->read)
+				fsd->methods |= HAS_READ;
+			if (ops->write)
+				fsd->methods |= HAS_WRITE;
 		} else {
-			fsd->real_fops = (void *)((unsigned long)d_fsd &
-						~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
-			fsd->short_fops = NULL;
+			const struct file_operations *ops;
+			ops = fsd->real_fops = DEBUGFS_I(inode)->real_fops;
+			if (ops->llseek)
+				fsd->methods |= HAS_LSEEK;
+			if (ops->read)
+				fsd->methods |= HAS_READ;
+			if (ops->write)
+				fsd->methods |= HAS_WRITE;
+			if (ops->unlocked_ioctl)
+				fsd->methods |= HAS_IOCTL;
+			if (ops->poll)
+				fsd->methods |= HAS_POLL;
 		}
 		refcount_set(&fsd->active_users, 1);
 		init_completion(&fsd->active_users_drained);
 		INIT_LIST_HEAD(&fsd->cancellations);
 		mutex_init(&fsd->cancellations_mtx);
 
-		if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
+		d_fsd = cmpxchg(&dentry->d_fsdata, NULL, fsd);
+		if (d_fsd) {
 			mutex_destroy(&fsd->cancellations_mtx);
 			kfree(fsd);
-			fsd = READ_ONCE(dentry->d_fsdata);
+			fsd = d_fsd;
 		}
 	}
 
@@ -208,8 +231,7 @@ void debugfs_enter_cancellation(struct file *file,
 		return;
 
 	fsd = READ_ONCE(dentry->d_fsdata);
-	if (WARN_ON(!fsd ||
-		    ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)))
+	if (WARN_ON(!fsd))
 		return;
 
 	mutex_lock(&fsd->cancellations_mtx);
@@ -240,8 +262,7 @@ void debugfs_leave_cancellation(struct file *file,
 		return;
 
 	fsd = READ_ONCE(dentry->d_fsdata);
-	if (WARN_ON(!fsd ||
-		    ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)))
+	if (WARN_ON(!fsd))
 		return;
 
 	mutex_lock(&fsd->cancellations_mtx);
@@ -322,13 +343,16 @@ const struct file_operations debugfs_open_proxy_file_operations = {
 #define PROTO(args...) args
 #define ARGS(args...) args
 
-#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args)		\
+#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args, bit, ret)	\
 static ret_type full_proxy_ ## name(proto)				\
 {									\
-	struct dentry *dentry = F_DENTRY(filp);			\
+	struct dentry *dentry = F_DENTRY(filp);				\
+	struct debugfs_fsdata *fsd = dentry->d_fsdata;			\
 	const struct file_operations *real_fops;			\
 	ret_type r;							\
 									\
+	if (!(fsd->methods & bit))					\
+		return ret;						\
 	r = debugfs_file_get(dentry);					\
 	if (unlikely(r))						\
 		return r;						\
@@ -338,17 +362,18 @@ static ret_type full_proxy_ ## name(proto)				\
 	return r;							\
 }
 
-#define FULL_PROXY_FUNC_BOTH(name, ret_type, filp, proto, args)		\
+#define FULL_PROXY_FUNC_BOTH(name, ret_type, filp, proto, args, bit, ret)	\
 static ret_type full_proxy_ ## name(proto)				\
 {									\
 	struct dentry *dentry = F_DENTRY(filp);				\
-	struct debugfs_fsdata *fsd;					\
+	struct debugfs_fsdata *fsd = dentry->d_fsdata;			\
 	ret_type r;							\
 									\
+	if (!(fsd->methods & bit))					\
+		return ret;						\
 	r = debugfs_file_get(dentry);					\
 	if (unlikely(r))						\
 		return r;						\
-	fsd = dentry->d_fsdata;						\
 	if (fsd->real_fops)						\
 		r = fsd->real_fops->name(args);				\
 	else								\
@@ -359,29 +384,32 @@ static ret_type full_proxy_ ## name(proto)				\
 
 FULL_PROXY_FUNC_BOTH(llseek, loff_t, filp,
 		     PROTO(struct file *filp, loff_t offset, int whence),
-		     ARGS(filp, offset, whence));
+		     ARGS(filp, offset, whence), HAS_LSEEK, -ESPIPE);
 
 FULL_PROXY_FUNC_BOTH(read, ssize_t, filp,
 		     PROTO(struct file *filp, char __user *buf, size_t size,
 			   loff_t *ppos),
-		     ARGS(filp, buf, size, ppos));
+		     ARGS(filp, buf, size, ppos), HAS_READ, -EINVAL);
 
 FULL_PROXY_FUNC_BOTH(write, ssize_t, filp,
 		     PROTO(struct file *filp, const char __user *buf,
 			   size_t size, loff_t *ppos),
-		     ARGS(filp, buf, size, ppos));
+		     ARGS(filp, buf, size, ppos), HAS_WRITE, -EINVAL);
 
 FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
 		PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
-		ARGS(filp, cmd, arg));
+		ARGS(filp, cmd, arg), HAS_IOCTL, -ENOTTY);
 
 static __poll_t full_proxy_poll(struct file *filp,
 				struct poll_table_struct *wait)
 {
 	struct dentry *dentry = F_DENTRY(filp);
+	struct debugfs_fsdata *fsd = dentry->d_fsdata;
 	__poll_t r = 0;
 	const struct file_operations *real_fops;
 
+	if (!(fsd->methods & HAS_POLL))
+		return DEFAULT_POLLMASK;
 	if (debugfs_file_get(dentry))
 		return EPOLLHUP;
 
@@ -393,9 +421,7 @@ static __poll_t full_proxy_poll(struct file *filp,
 
 static int full_proxy_release(struct inode *inode, struct file *filp)
 {
-	const struct dentry *dentry = F_DENTRY(filp);
 	const struct file_operations *real_fops = debugfs_real_fops(filp);
-	const struct file_operations *proxy_fops = filp->f_op;
 	int r = 0;
 
 	/*
@@ -404,49 +430,21 @@ static int full_proxy_release(struct inode *inode, struct file *filp)
 	 * not to leak any resources. Releasers must not assume that
 	 * ->i_private is still being meaningful here.
 	 */
-	if (real_fops && real_fops->release)
+	if (real_fops->release)
 		r = real_fops->release(inode, filp);
 
-	replace_fops(filp, d_inode(dentry)->i_fop);
-	kfree(proxy_fops);
 	fops_put(real_fops);
 	return r;
 }
 
-static void __full_proxy_fops_init(struct file_operations *proxy_fops,
-				   struct debugfs_fsdata *fsd)
-{
-	proxy_fops->release = full_proxy_release;
-
-	if ((fsd->real_fops && fsd->real_fops->llseek) ||
-	    (fsd->short_fops && fsd->short_fops->llseek))
-		proxy_fops->llseek = full_proxy_llseek;
-
-	if ((fsd->real_fops && fsd->real_fops->read) ||
-	    (fsd->short_fops && fsd->short_fops->read))
-		proxy_fops->read = full_proxy_read;
-
-	if ((fsd->real_fops && fsd->real_fops->write) ||
-	    (fsd->short_fops && fsd->short_fops->write))
-		proxy_fops->write = full_proxy_write;
-
-	if (fsd->real_fops && fsd->real_fops->poll)
-		proxy_fops->poll = full_proxy_poll;
-
-	if (fsd->real_fops && fsd->real_fops->unlocked_ioctl)
-		proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
-}
-
-static int full_proxy_open(struct inode *inode, struct file *filp,
-			   enum dbgfs_get_mode mode)
+static int full_proxy_open_regular(struct inode *inode, struct file *filp)
 {
 	struct dentry *dentry = F_DENTRY(filp);
 	const struct file_operations *real_fops;
-	struct file_operations *proxy_fops = NULL;
 	struct debugfs_fsdata *fsd;
 	int r;
 
-	r = __debugfs_file_get(dentry, mode);
+	r = __debugfs_file_get(dentry, DBGFS_GET_REGULAR);
 	if (r)
 		return r == -EIO ? -ENOENT : r;
 
@@ -456,7 +454,7 @@ static int full_proxy_open(struct inode *inode, struct file *filp,
 	if (r)
 		goto out;
 
-	if (real_fops && !fops_get(real_fops)) {
+	if (!fops_get(real_fops)) {
 #ifdef CONFIG_MODULES
 		if (real_fops->owner &&
 		    real_fops->owner->state == MODULE_STATE_GOING) {
@@ -472,55 +470,52 @@ static int full_proxy_open(struct inode *inode, struct file *filp,
 		goto out;
 	}
 
-	proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
-	if (!proxy_fops) {
-		r = -ENOMEM;
-		goto free_proxy;
-	}
-	__full_proxy_fops_init(proxy_fops, fsd);
-	replace_fops(filp, proxy_fops);
-
-	if (!real_fops || real_fops->open) {
-		if (real_fops)
-			r = real_fops->open(inode, filp);
-		else
-			r = simple_open(inode, filp);
+	if (real_fops->open) {
+		r = real_fops->open(inode, filp);
 		if (r) {
-			replace_fops(filp, d_inode(dentry)->i_fop);
-			goto free_proxy;
-		} else if (filp->f_op != proxy_fops) {
+			fops_put(real_fops);
+		} else if (filp->f_op != &debugfs_full_proxy_file_operations) {
 			/* No protection against file removal anymore. */
 			WARN(1, "debugfs file owner replaced proxy fops: %pd",
 				dentry);
-			goto free_proxy;
+			fops_put(real_fops);
 		}
 	}
-
-	goto out;
-free_proxy:
-	kfree(proxy_fops);
-	fops_put(real_fops);
 out:
 	debugfs_file_put(dentry);
 	return r;
 }
 
-static int full_proxy_open_regular(struct inode *inode, struct file *filp)
-{
-	return full_proxy_open(inode, filp, DBGFS_GET_REGULAR);
-}
-
 const struct file_operations debugfs_full_proxy_file_operations = {
 	.open = full_proxy_open_regular,
+	.release = full_proxy_release,
+	.llseek = full_proxy_llseek,
+	.read = full_proxy_read,
+	.write = full_proxy_write,
+	.poll = full_proxy_poll,
+	.unlocked_ioctl = full_proxy_unlocked_ioctl
 };
 
 static int full_proxy_open_short(struct inode *inode, struct file *filp)
 {
-	return full_proxy_open(inode, filp, DBGFS_GET_SHORT);
+	struct dentry *dentry = F_DENTRY(filp);
+	int r;
+
+	r = __debugfs_file_get(dentry, DBGFS_GET_SHORT);
+	if (r)
+		return r == -EIO ? -ENOENT : r;
+	r = debugfs_locked_down(inode, filp, NULL);
+	if (!r)
+		r = simple_open(inode, filp);
+	debugfs_file_put(dentry);
+	return r;
 }
 
 const struct file_operations debugfs_full_short_proxy_file_operations = {
 	.open = full_proxy_open_short,
+	.llseek = full_proxy_llseek,
+	.read = full_proxy_read,
+	.write = full_proxy_write,
 };
 
 ssize_t debugfs_attr_read(struct file *file, char __user *buf,
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index e752009de929..75715d8877ee 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -208,16 +208,34 @@ static int debugfs_show_options(struct seq_file *m, struct dentry *root)
 	return 0;
 }
 
+static struct kmem_cache *debugfs_inode_cachep __ro_after_init;
+
+static void init_once(void *foo)
+{
+	struct debugfs_inode_info *info = foo;
+	inode_init_once(&info->vfs_inode);
+}
+
+static struct inode *debugfs_alloc_inode(struct super_block *sb)
+{
+	struct debugfs_inode_info *info;
+	info = alloc_inode_sb(sb, debugfs_inode_cachep, GFP_KERNEL);
+	if (!info)
+		return NULL;
+	return &info->vfs_inode;
+}
+
 static void debugfs_free_inode(struct inode *inode)
 {
 	if (S_ISLNK(inode->i_mode))
 		kfree(inode->i_link);
-	free_inode_nonrcu(inode);
+	kmem_cache_free(debugfs_inode_cachep, DEBUGFS_I(inode));
 }
 
 static const struct super_operations debugfs_super_operations = {
 	.statfs		= simple_statfs,
 	.show_options	= debugfs_show_options,
+	.alloc_inode	= debugfs_alloc_inode,
 	.free_inode	= debugfs_free_inode,
 };
 
@@ -225,23 +243,18 @@ static void debugfs_release_dentry(struct dentry *dentry)
 {
 	struct debugfs_fsdata *fsd = dentry->d_fsdata;
 
-	if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)
-		return;
-
-	/* check it wasn't a dir (no fsdata) or automount (no real_fops) */
-	if (fsd && (fsd->real_fops || fsd->short_fops)) {
+	if (fsd) {
 		WARN_ON(!list_empty(&fsd->cancellations));
 		mutex_destroy(&fsd->cancellations_mtx);
 	}
-
 	kfree(fsd);
 }
 
 static struct vfsmount *debugfs_automount(struct path *path)
 {
-	struct debugfs_fsdata *fsd = path->dentry->d_fsdata;
+	struct inode *inode = path->dentry->d_inode;
 
-	return fsd->automount(path->dentry, d_inode(path->dentry)->i_private);
+	return DEBUGFS_I(inode)->automount(path->dentry, inode->i_private);
 }
 
 static const struct dentry_operations debugfs_dops = {
@@ -411,6 +424,7 @@ static struct dentry *end_creating(struct dentry *dentry)
 
 static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
 				struct dentry *parent, void *data,
+				const void *aux,
 				const struct file_operations *proxy_fops,
 				const void *real_fops)
 {
@@ -441,9 +455,11 @@ static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
 	inode->i_private = data;
 
 	inode->i_op = &debugfs_file_inode_operations;
+	if (!real_fops)
+		proxy_fops = &debugfs_noop_file_operations;
 	inode->i_fop = proxy_fops;
-	dentry->d_fsdata = (void *)((unsigned long)real_fops |
-				DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
+	DEBUGFS_I(inode)->raw = real_fops;
+	DEBUGFS_I(inode)->aux = aux;
 
 	d_instantiate(dentry, inode);
 	fsnotify_create(d_inode(dentry->d_parent), dentry);
@@ -452,30 +468,22 @@ static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
 
 struct dentry *debugfs_create_file_full(const char *name, umode_t mode,
 					struct dentry *parent, void *data,
+					const void *aux,
 					const struct file_operations *fops)
 {
-	if (WARN_ON((unsigned long)fops &
-		    DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))
-		return ERR_PTR(-EINVAL);
-
-	return __debugfs_create_file(name, mode, parent, data,
-				fops ? &debugfs_full_proxy_file_operations :
-					&debugfs_noop_file_operations,
+	return __debugfs_create_file(name, mode, parent, data, aux,
+				&debugfs_full_proxy_file_operations,
 				fops);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file_full);
 
 struct dentry *debugfs_create_file_short(const char *name, umode_t mode,
-					 struct dentry *parent, void *data,
-					 const struct debugfs_short_fops *fops)
+					struct dentry *parent, void *data,
+					const void *aux,
+					const struct debugfs_short_fops *fops)
 {
-	if (WARN_ON((unsigned long)fops &
-		    DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))
-		return ERR_PTR(-EINVAL);
-
-	return __debugfs_create_file(name, mode, parent, data,
-				fops ? &debugfs_full_short_proxy_file_operations :
-					&debugfs_noop_file_operations,
+	return __debugfs_create_file(name, mode, parent, data, aux,
+				&debugfs_full_short_proxy_file_operations,
 				fops);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file_short);
@@ -512,9 +520,8 @@ struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
 				   const struct file_operations *fops)
 {
 
-	return __debugfs_create_file(name, mode, parent, data,
-				fops ? &debugfs_open_proxy_file_operations :
-					&debugfs_noop_file_operations,
+	return __debugfs_create_file(name, mode, parent, data, NULL,
+				&debugfs_open_proxy_file_operations,
 				fops);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe);
@@ -624,23 +631,13 @@ struct dentry *debugfs_create_automount(const char *name,
 					void *data)
 {
 	struct dentry *dentry = start_creating(name, parent);
-	struct debugfs_fsdata *fsd;
 	struct inode *inode;
 
 	if (IS_ERR(dentry))
 		return dentry;
 
-	fsd = kzalloc(sizeof(*fsd), GFP_KERNEL);
-	if (!fsd) {
-		failed_creating(dentry);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	fsd->automount = f;
-
 	if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
 		failed_creating(dentry);
-		kfree(fsd);
 		return ERR_PTR(-EPERM);
 	}
 
@@ -648,14 +645,13 @@ struct dentry *debugfs_create_automount(const char *name,
 	if (unlikely(!inode)) {
 		pr_err("out of free dentries, can not create automount '%s'\n",
 		       name);
-		kfree(fsd);
 		return failed_creating(dentry);
 	}
 
 	make_empty_dir_inode(inode);
 	inode->i_flags |= S_AUTOMOUNT;
 	inode->i_private = data;
-	dentry->d_fsdata = fsd;
+	DEBUGFS_I(inode)->automount = f;
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
 	d_instantiate(dentry, inode);
@@ -730,7 +726,7 @@ static void __debugfs_file_removed(struct dentry *dentry)
 	 */
 	smp_mb();
 	fsd = READ_ONCE(dentry->d_fsdata);
-	if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)
+	if (!fsd)
 		return;
 
 	/* if this was the last reference, we're done */
@@ -834,76 +830,70 @@ void debugfs_lookup_and_remove(const char *name, struct dentry *parent)
 EXPORT_SYMBOL_GPL(debugfs_lookup_and_remove);
 
 /**
- * debugfs_rename - rename a file/directory in the debugfs filesystem
- * @old_dir: a pointer to the parent dentry for the renamed object. This
- *          should be a directory dentry.
- * @old_dentry: dentry of an object to be renamed.
- * @new_dir: a pointer to the parent dentry where the object should be
- *          moved. This should be a directory dentry.
- * @new_name: a pointer to a string containing the target name.
+ * debugfs_change_name - rename a file/directory in the debugfs filesystem
+ * @dentry: dentry of an object to be renamed.
+ * @fmt: format for new name
  *
  * This function renames a file/directory in debugfs.  The target must not
  * exist for rename to succeed.
  *
- * This function will return a pointer to old_dentry (which is updated to
- * reflect renaming) if it succeeds. If an error occurs, ERR_PTR(-ERROR)
- * will be returned.
+ * This function will return 0 on success and -E... on failure.
  *
  * If debugfs is not enabled in the kernel, the value -%ENODEV will be
  * returned.
  */
-struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
-		struct dentry *new_dir, const char *new_name)
+int __printf(2, 3) debugfs_change_name(struct dentry *dentry, const char *fmt, ...)
 {
-	int error;
-	struct dentry *dentry = NULL, *trap;
+	int error = 0;
+	const char *new_name;
 	struct name_snapshot old_name;
+	struct dentry *parent, *target;
+	struct inode *dir;
+	va_list ap;
 
-	if (IS_ERR(old_dir))
-		return old_dir;
-	if (IS_ERR(new_dir))
-		return new_dir;
-	if (IS_ERR_OR_NULL(old_dentry))
-		return old_dentry;
-
-	trap = lock_rename(new_dir, old_dir);
-	/* Source or destination directories don't exist? */
-	if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir))
-		goto exit;
-	/* Source does not exist, cyclic rename, or mountpoint? */
-	if (d_really_is_negative(old_dentry) || old_dentry == trap ||
-	    d_mountpoint(old_dentry))
-		goto exit;
-	dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
-	/* Lookup failed, cyclic rename or target exists? */
-	if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry))
-		goto exit;
-
-	take_dentry_name_snapshot(&old_name, old_dentry);
-
-	error = simple_rename(&nop_mnt_idmap, d_inode(old_dir), old_dentry,
-			      d_inode(new_dir), dentry, 0);
-	if (error) {
-		release_dentry_name_snapshot(&old_name);
-		goto exit;
+	if (IS_ERR_OR_NULL(dentry))
+		return 0;
+
+	va_start(ap, fmt);
+	new_name = kvasprintf_const(GFP_KERNEL, fmt, ap);
+	va_end(ap);
+	if (!new_name)
+		return -ENOMEM;
+
+	parent = dget_parent(dentry);
+	dir = d_inode(parent);
+	inode_lock(dir);
+
+	take_dentry_name_snapshot(&old_name, dentry);
+
+	if (WARN_ON_ONCE(dentry->d_parent != parent)) {
+		error = -EINVAL;
+		goto out;
 	}
-	d_move(old_dentry, dentry);
-	fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name,
-		d_is_dir(old_dentry),
-		NULL, old_dentry);
+	if (strcmp(old_name.name.name, new_name) == 0)
+		goto out;
+	target = lookup_one_len(new_name, parent, strlen(new_name));
+	if (IS_ERR(target)) {
+		error = PTR_ERR(target);
+		goto out;
+	}
+	if (d_really_is_positive(target)) {
+		dput(target);
+		error = -EINVAL;
+		goto out;
+	}
+	simple_rename_timestamp(dir, dentry, dir, target);
+	d_move(dentry, target);
+	dput(target);
+	fsnotify_move(dir, dir, &old_name.name, d_is_dir(dentry), NULL, dentry);
+out:
 	release_dentry_name_snapshot(&old_name);
-	unlock_rename(new_dir, old_dir);
-	dput(dentry);
-	return old_dentry;
-exit:
-	if (dentry && !IS_ERR(dentry))
-		dput(dentry);
-	unlock_rename(new_dir, old_dir);
-	if (IS_ERR(dentry))
-		return dentry;
-	return ERR_PTR(-EINVAL);
+	inode_unlock(dir);
+	dput(parent);
+	kfree_const(new_name);
+	return error;
 }
-EXPORT_SYMBOL_GPL(debugfs_rename);
+EXPORT_SYMBOL_GPL(debugfs_change_name);
 
 /**
  * debugfs_initialized - Tells whether debugfs has been registered
@@ -939,12 +929,22 @@ static int __init debugfs_init(void)
 	if (retval)
 		return retval;
 
-	retval = register_filesystem(&debug_fs_type);
-	if (retval)
+	debugfs_inode_cachep = kmem_cache_create("debugfs_inode_cache",
+				sizeof(struct debugfs_inode_info), 0,
+				SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
+				init_once);
+	if (debugfs_inode_cachep == NULL) {
 		sysfs_remove_mount_point(kernel_kobj, "debug");
-	else
-		debugfs_registered = true;
+		return -ENOMEM;
+	}
 
-	return retval;
+	retval = register_filesystem(&debug_fs_type);
+	if (retval) { // Really not going to happen
+		sysfs_remove_mount_point(kernel_kobj, "debug");
+		kmem_cache_destroy(debugfs_inode_cachep);
+		return retval;
+	}
+	debugfs_registered = true;
+	return 0;
 }
 core_initcall(debugfs_init);
diff --git a/fs/debugfs/internal.h b/fs/debugfs/internal.h
index bbae4a228ef4..93483fe84425 100644
--- a/fs/debugfs/internal.h
+++ b/fs/debugfs/internal.h
@@ -11,6 +11,22 @@
 
 struct file_operations;
 
+struct debugfs_inode_info {
+	struct inode vfs_inode;
+	union {
+		const void *raw;
+		const struct file_operations *real_fops;
+		const struct debugfs_short_fops *short_fops;
+		debugfs_automount_t automount;
+	};
+	const void *aux;
+};
+
+static inline struct debugfs_inode_info *DEBUGFS_I(struct inode *inode)
+{
+	return container_of(inode, struct debugfs_inode_info, vfs_inode);
+}
+
 /* declared over in file.c */
 extern const struct file_operations debugfs_noop_file_operations;
 extern const struct file_operations debugfs_open_proxy_file_operations;
@@ -20,29 +36,25 @@ extern const struct file_operations debugfs_full_short_proxy_file_operations;
 struct debugfs_fsdata {
 	const struct file_operations *real_fops;
 	const struct debugfs_short_fops *short_fops;
-	union {
-		/* automount_fn is used when real_fops is NULL */
-		debugfs_automount_t automount;
-		struct {
-			refcount_t active_users;
-			struct completion active_users_drained;
-
-			/* protect cancellations */
-			struct mutex cancellations_mtx;
-			struct list_head cancellations;
-		};
+	struct {
+		refcount_t active_users;
+		struct completion active_users_drained;
+
+		/* protect cancellations */
+		struct mutex cancellations_mtx;
+		struct list_head cancellations;
+		unsigned int methods;
 	};
 };
 
-/*
- * A dentry's ->d_fsdata either points to the real fops or to a
- * dynamically allocated debugfs_fsdata instance.
- * In order to distinguish between these two cases, a real fops
- * pointer gets its lowest bit set.
- */
-#define DEBUGFS_FSDATA_IS_REAL_FOPS_BIT BIT(0)
+enum {
+	HAS_READ = 1,
+	HAS_WRITE = 2,
+	HAS_LSEEK = 4,
+	HAS_POLL = 8,
+	HAS_IOCTL = 16
+};
 
-/* Access BITS */
 #define DEBUGFS_ALLOW_API	BIT(0)
 #define DEBUGFS_ALLOW_MOUNT	BIT(1)
 
diff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c
index 1b508f543384..9729f071c5aa 100644
--- a/fs/orangefs/orangefs-debugfs.c
+++ b/fs/orangefs/orangefs-debugfs.c
@@ -206,8 +206,8 @@ static void orangefs_kernel_debug_init(void)
 		pr_info("%s: overflow 1!\n", __func__);
 	}
 
-	debugfs_create_file(ORANGEFS_KMOD_DEBUG_FILE, 0444, debug_dir, k_buffer,
-			    &kernel_debug_fops);
+	debugfs_create_file_aux_num(ORANGEFS_KMOD_DEBUG_FILE, 0444, debug_dir, k_buffer,
+			    0, &kernel_debug_fops);
 }
 
 
@@ -306,11 +306,10 @@ static void orangefs_client_debug_init(void)
 		pr_info("%s: overflow! 2\n", __func__);
 	}
 
-	client_debug_dentry = debugfs_create_file(ORANGEFS_CLIENT_DEBUG_FILE,
-						  0444,
-						  debug_dir,
-						  c_buffer,
-						  &kernel_debug_fops);
+	client_debug_dentry = debugfs_create_file_aux_num(
+					  ORANGEFS_CLIENT_DEBUG_FILE,
+					  0444, debug_dir, c_buffer, 1,
+					  &kernel_debug_fops);
 }
 
 /* open ORANGEFS_KMOD_DEBUG_FILE or ORANGEFS_CLIENT_DEBUG_FILE.*/
@@ -418,8 +417,7 @@ static ssize_t orangefs_debug_write(struct file *file,
 	 * A service operation is required to set a new client-side
 	 * debug mask.
 	 */
-	if (!strcmp(file->f_path.dentry->d_name.name,
-		    ORANGEFS_KMOD_DEBUG_FILE)) {
+	if (!debugfs_get_aux_num(file)) {	// kernel-debug
 		debug_string_to_mask(buf, &orangefs_gossip_debug_mask, 0);
 		debug_mask_to_string(&orangefs_gossip_debug_mask, 0);
 		debug_string = kernel_debug_string;
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 785408861c01..6931308876c4 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -817,7 +817,7 @@ EXPORT_SYMBOL_GPL(sysfs_emit_at);
  * Returns number of bytes written to @buf.
  */
 ssize_t sysfs_bin_attr_simple_read(struct file *file, struct kobject *kobj,
-				   struct bin_attribute *attr, char *buf,
+				   const struct bin_attribute *attr, char *buf,
 				   loff_t off, size_t count)
 {
 	memcpy(buf, attr->private + off, count);