From e09ddf36dd986e91edd69a0355bdd44cb738b45e Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 13:50:23 -0500
Subject: debugfs_{mkdir,create,link}(): get rid of redundant argument

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 05f2960..adaaa04 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -89,8 +89,9 @@ static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
 	return error;
 }
 
-static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int debugfs_mkdir(struct dentry *dentry, umode_t mode)
 {
+	struct inode *dir = dentry->d_parent->d_inode;
 	int res;
 
 	mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
@@ -102,16 +103,18 @@ static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	return res;
 }
 
-static int debugfs_link(struct inode *dir, struct dentry *dentry, umode_t mode,
+static int debugfs_link(struct dentry *dentry, umode_t mode,
 			void *data)
 {
+	struct inode *dir = dentry->d_parent->d_inode;
 	mode = (mode & S_IALLUGO) | S_IFLNK;
 	return debugfs_mknod(dir, dentry, mode, 0, data, NULL);
 }
 
-static int debugfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+static int debugfs_create(struct dentry *dentry, umode_t mode,
 			  void *data, const struct file_operations *fops)
 {
+	struct inode *dir = dentry->d_parent->d_inode;
 	int res;
 
 	mode = (mode & S_IALLUGO) | S_IFREG;
@@ -329,16 +332,14 @@ static struct dentry *__create_file(const char *name, umode_t mode,
 	if (!IS_ERR(dentry)) {
 		switch (mode & S_IFMT) {
 		case S_IFDIR:
-			error = debugfs_mkdir(parent->d_inode, dentry, mode);
+			error = debugfs_mkdir(dentry, mode);
 
 			break;
 		case S_IFLNK:
-			error = debugfs_link(parent->d_inode, dentry, mode,
-					     data);
+			error = debugfs_link(dentry, mode, data);
 			break;
 		default:
-			error = debugfs_create(parent->d_inode, dentry, mode,
-					       data, fops);
+			error = debugfs_create(dentry, mode, data, fops);
 			break;
 		}
 		dput(dentry);
-- 
cgit v0.10.2


From 190afd81e4a5f24d1db6c774ca7f18acde2fca30 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 13:55:55 -0500
Subject: debugfs: split the beginning and the end of __create_file() off

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index adaaa04..100186c 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -305,11 +305,9 @@ static struct file_system_type debug_fs_type = {
 };
 MODULE_ALIAS_FS("debugfs");
 
-static struct dentry *__create_file(const char *name, umode_t mode,
-				    struct dentry *parent, void *data,
-				    const struct file_operations *fops)
+static struct dentry *start_creating(const char *name, struct dentry *parent)
 {
-	struct dentry *dentry = NULL;
+	struct dentry *dentry;
 	int error;
 
 	pr_debug("debugfs: creating file '%s'\n",name);
@@ -317,7 +315,7 @@ static struct dentry *__create_file(const char *name, umode_t mode,
 	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
 			      &debugfs_mount_count);
 	if (error)
-		goto exit;
+		return ERR_PTR(error);
 
 	/* If the parent is not specified, we create it in the root.
 	 * We need the root dentry to do this, which is in the super
@@ -329,32 +327,51 @@ static struct dentry *__create_file(const char *name, umode_t mode,
 
 	mutex_lock(&parent->d_inode->i_mutex);
 	dentry = lookup_one_len(name, parent, strlen(name));
-	if (!IS_ERR(dentry)) {
-		switch (mode & S_IFMT) {
-		case S_IFDIR:
-			error = debugfs_mkdir(dentry, mode);
-
-			break;
-		case S_IFLNK:
-			error = debugfs_link(dentry, mode, data);
-			break;
-		default:
-			error = debugfs_create(dentry, mode, data, fops);
-			break;
-		}
+	if (!IS_ERR(dentry) && dentry->d_inode) {
 		dput(dentry);
-	} else
-		error = PTR_ERR(dentry);
-	mutex_unlock(&parent->d_inode->i_mutex);
+		dentry = ERR_PTR(-EEXIST);
+	}
+	if (IS_ERR(dentry))
+		mutex_unlock(&parent->d_inode->i_mutex);
+	return dentry;
+}
+
+static struct dentry *end_creating(struct dentry *dentry, int error)
+{
+	mutex_unlock(&dentry->d_parent->d_inode->i_mutex);
+	dput(dentry);
 
 	if (error) {
 		dentry = NULL;
 		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 	}
-exit:
 	return dentry;
 }
 
+static struct dentry *__create_file(const char *name, umode_t mode,
+				    struct dentry *parent, void *data,
+				    const struct file_operations *fops)
+{
+	struct dentry *dentry = start_creating(name, parent);
+	int error;
+
+	if (IS_ERR(dentry))
+		return NULL;
+
+	switch (mode & S_IFMT) {
+	case S_IFDIR:
+		error = debugfs_mkdir(dentry, mode);
+		break;
+	case S_IFLNK:
+		error = debugfs_link(dentry, mode, data);
+		break;
+	default:
+		error = debugfs_create(dentry, mode, data, fops);
+		break;
+	}
+	return end_creating(dentry, error);
+}
+
 /**
  * debugfs_create_file - create a file in the debugfs filesystem
  * @name: a pointer to a string containing the name of the file to create.
-- 
cgit v0.10.2


From ad5abd5ba8c66ea44e24d7b6996e85ab83b412fc Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 14:02:31 -0500
Subject: debugfs: kill __create_file()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 100186c..18564b0 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -348,30 +348,6 @@ static struct dentry *end_creating(struct dentry *dentry, int error)
 	return dentry;
 }
 
-static struct dentry *__create_file(const char *name, umode_t mode,
-				    struct dentry *parent, void *data,
-				    const struct file_operations *fops)
-{
-	struct dentry *dentry = start_creating(name, parent);
-	int error;
-
-	if (IS_ERR(dentry))
-		return NULL;
-
-	switch (mode & S_IFMT) {
-	case S_IFDIR:
-		error = debugfs_mkdir(dentry, mode);
-		break;
-	case S_IFLNK:
-		error = debugfs_link(dentry, mode, data);
-		break;
-	default:
-		error = debugfs_create(dentry, mode, data, fops);
-		break;
-	}
-	return end_creating(dentry, error);
-}
-
 /**
  * debugfs_create_file - create a file in the debugfs filesystem
  * @name: a pointer to a string containing the name of the file to create.
@@ -402,15 +378,19 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 				   struct dentry *parent, void *data,
 				   const struct file_operations *fops)
 {
-	switch (mode & S_IFMT) {
-	case S_IFREG:
-	case 0:
-		break;
-	default:
-		BUG();
-	}
+	struct dentry *dentry;
+	int error;
+
+	if (!(mode & S_IFMT))
+		mode |= S_IFREG;
+	BUG_ON(!S_ISREG(mode));
+	dentry = start_creating(name, parent);
+
+	if (IS_ERR(dentry))
+		return NULL;
 
-	return __create_file(name, mode, parent, data, fops);
+	error = debugfs_create(dentry, mode, data, fops);
+	return end_creating(dentry, error);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file);
 
@@ -434,8 +414,14 @@ EXPORT_SYMBOL_GPL(debugfs_create_file);
  */
 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 {
-	return __create_file(name, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
-				   parent, NULL, NULL);
+	struct dentry *dentry = start_creating(name, parent);
+	int error;
+
+	if (IS_ERR(dentry))
+		return NULL;
+
+	error = debugfs_mkdir(dentry, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
+	return end_creating(dentry, error);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_dir);
 
@@ -465,17 +451,26 @@ EXPORT_SYMBOL_GPL(debugfs_create_dir);
 struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 				      const char *target)
 {
-	struct dentry *result;
+	struct dentry *dentry;
 	char *link;
+	int error;
 
 	link = kstrdup(target, GFP_KERNEL);
 	if (!link)
 		return NULL;
 
-	result = __create_file(name, S_IFLNK | S_IRWXUGO, parent, link, NULL);
-	if (!result)
+	dentry = start_creating(name, parent);
+
+	if (IS_ERR(dentry)) {
 		kfree(link);
-	return result;
+		return NULL;
+	}
+
+	error = debugfs_link(dentry, S_IFLNK | S_IRWXUGO, link);
+	if (error)
+		kfree(link);
+
+	return end_creating(dentry, error);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_symlink);
 
-- 
cgit v0.10.2


From 9b73fab01bcd62530e8c9a5da44d3ed8a753b3eb Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 14:05:55 -0500
Subject: fold debugfs_link() into caller

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 18564b0..c69e00d 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -103,14 +103,6 @@ static int debugfs_mkdir(struct dentry *dentry, umode_t mode)
 	return res;
 }
 
-static int debugfs_link(struct dentry *dentry, umode_t mode,
-			void *data)
-{
-	struct inode *dir = dentry->d_parent->d_inode;
-	mode = (mode & S_IALLUGO) | S_IFLNK;
-	return debugfs_mknod(dir, dentry, mode, 0, data, NULL);
-}
-
 static int debugfs_create(struct dentry *dentry, umode_t mode,
 			  void *data, const struct file_operations *fops)
 {
@@ -466,7 +458,8 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 		return NULL;
 	}
 
-	error = debugfs_link(dentry, S_IFLNK | S_IRWXUGO, link);
+	error = debugfs_mknod(dentry->d_parent->d_inode, dentry,
+			      S_IFLNK | S_IRWXUGO, 0, link, NULL);
 	if (error)
 		kfree(link);
 
-- 
cgit v0.10.2


From 160f7592f2364b47c615cff96117f0877d58e427 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 14:09:49 -0500
Subject: debugfs_mknod(): get rid useless arguments

dev is always zero, dir was only used to get its ->i_sb, which is
equal to ->d_sb of dentry...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index c69e00d..bc02e20 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -70,23 +70,18 @@ static struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev
 }
 
 /* SMP-safe */
-static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
-			 umode_t mode, dev_t dev, void *data,
+static int debugfs_mknod(struct dentry *dentry,
+			 umode_t mode, void *data,
 			 const struct file_operations *fops)
 {
 	struct inode *inode;
-	int error = -EPERM;
 
-	if (dentry->d_inode)
-		return -EEXIST;
-
-	inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);
-	if (inode) {
-		d_instantiate(dentry, inode);
-		dget(dentry);
-		error = 0;
-	}
-	return error;
+	inode = debugfs_get_inode(dentry->d_sb, mode, 0, data, fops);
+	if (unlikely(!inode))
+		return -EPERM;
+	d_instantiate(dentry, inode);
+	dget(dentry);
+	return 0;
 }
 
 static int debugfs_mkdir(struct dentry *dentry, umode_t mode)
@@ -95,7 +90,7 @@ static int debugfs_mkdir(struct dentry *dentry, umode_t mode)
 	int res;
 
 	mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
-	res = debugfs_mknod(dir, dentry, mode, 0, NULL, NULL);
+	res = debugfs_mknod(dentry, mode, NULL, NULL);
 	if (!res) {
 		inc_nlink(dir);
 		fsnotify_mkdir(dir, dentry);
@@ -110,7 +105,7 @@ static int debugfs_create(struct dentry *dentry, umode_t mode,
 	int res;
 
 	mode = (mode & S_IALLUGO) | S_IFREG;
-	res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
+	res = debugfs_mknod(dentry, mode, data, fops);
 	if (!res)
 		fsnotify_create(dir, dentry);
 	return res;
@@ -458,8 +453,7 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 		return NULL;
 	}
 
-	error = debugfs_mknod(dentry->d_parent->d_inode, dentry,
-			      S_IFLNK | S_IRWXUGO, 0, link, NULL);
+	error = debugfs_mknod(dentry, S_IFLNK | S_IRWXUGO, link, NULL);
 	if (error)
 		kfree(link);
 
-- 
cgit v0.10.2


From 02538a75ba176d286a421d1e41a66061f407c3b3 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 14:15:18 -0500
Subject: fold debugfs_mkdir() into caller

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index bc02e20..8d12935 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -84,20 +84,6 @@ static int debugfs_mknod(struct dentry *dentry,
 	return 0;
 }
 
-static int debugfs_mkdir(struct dentry *dentry, umode_t mode)
-{
-	struct inode *dir = dentry->d_parent->d_inode;
-	int res;
-
-	mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
-	res = debugfs_mknod(dentry, mode, NULL, NULL);
-	if (!res) {
-		inc_nlink(dir);
-		fsnotify_mkdir(dir, dentry);
-	}
-	return res;
-}
-
 static int debugfs_create(struct dentry *dentry, umode_t mode,
 			  void *data, const struct file_operations *fops)
 {
@@ -407,7 +393,12 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 	if (IS_ERR(dentry))
 		return NULL;
 
-	error = debugfs_mkdir(dentry, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
+	error = debugfs_mknod(dentry, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
+			      NULL, NULL);
+	if (!error) {
+		inc_nlink(dentry->d_parent->d_inode);
+		fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
+	}
 	return end_creating(dentry, error);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_dir);
-- 
cgit v0.10.2


From 3473cde5655cf4501cadb8ed11ab8aad1484b377 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 14:17:11 -0500
Subject: fold debugfs_create() into caller

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 8d12935..778c0e3 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -84,19 +84,6 @@ static int debugfs_mknod(struct dentry *dentry,
 	return 0;
 }
 
-static int debugfs_create(struct dentry *dentry, umode_t mode,
-			  void *data, const struct file_operations *fops)
-{
-	struct inode *dir = dentry->d_parent->d_inode;
-	int res;
-
-	mode = (mode & S_IALLUGO) | S_IFREG;
-	res = debugfs_mknod(dentry, mode, data, fops);
-	if (!res)
-		fsnotify_create(dir, dentry);
-	return res;
-}
-
 static inline int debugfs_positive(struct dentry *dentry)
 {
 	return dentry->d_inode && !d_unhashed(dentry);
@@ -362,7 +349,9 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 	if (IS_ERR(dentry))
 		return NULL;
 
-	error = debugfs_create(dentry, mode, data, fops);
+	error = debugfs_mknod(dentry, mode, data, fops);
+	if (!error)
+		fsnotify_create(dentry->d_parent->d_inode, dentry);
 	return end_creating(dentry, error);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file);
-- 
cgit v0.10.2


From 680b302409cdc87c2000a31f2ceb2951bd642260 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 14:31:32 -0500
Subject: fold debugfs_mknod() into callers

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 778c0e3..b765c04 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -69,21 +69,6 @@ static struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev
 	return inode;
 }
 
-/* SMP-safe */
-static int debugfs_mknod(struct dentry *dentry,
-			 umode_t mode, void *data,
-			 const struct file_operations *fops)
-{
-	struct inode *inode;
-
-	inode = debugfs_get_inode(dentry->d_sb, mode, 0, data, fops);
-	if (unlikely(!inode))
-		return -EPERM;
-	d_instantiate(dentry, inode);
-	dget(dentry);
-	return 0;
-}
-
 static inline int debugfs_positive(struct dentry *dentry)
 {
 	return dentry->d_inode && !d_unhashed(dentry);
@@ -339,7 +324,7 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 				   const struct file_operations *fops)
 {
 	struct dentry *dentry;
-	int error;
+	struct inode *inode;
 
 	if (!(mode & S_IFMT))
 		mode |= S_IFREG;
@@ -349,10 +334,14 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 	if (IS_ERR(dentry))
 		return NULL;
 
-	error = debugfs_mknod(dentry, mode, data, fops);
-	if (!error)
-		fsnotify_create(dentry->d_parent->d_inode, dentry);
-	return end_creating(dentry, error);
+	inode = debugfs_get_inode(dentry->d_sb, mode, 0, data, fops);
+	if (unlikely(!inode))
+		return end_creating(dentry, -ENOMEM);
+
+	d_instantiate(dentry, inode);
+	dget(dentry);
+	fsnotify_create(dentry->d_parent->d_inode, dentry);
+	return end_creating(dentry, 0);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file);
 
@@ -377,18 +366,22 @@ EXPORT_SYMBOL_GPL(debugfs_create_file);
 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 {
 	struct dentry *dentry = start_creating(name, parent);
-	int error;
+	struct inode *inode;
 
 	if (IS_ERR(dentry))
 		return NULL;
 
-	error = debugfs_mknod(dentry, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
-			      NULL, NULL);
-	if (!error) {
-		inc_nlink(dentry->d_parent->d_inode);
-		fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
-	}
-	return end_creating(dentry, error);
+	inode = debugfs_get_inode(dentry->d_sb,
+				  S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
+				  0, NULL, NULL);
+	if (unlikely(!inode))
+		return end_creating(dentry, -ENOMEM);
+
+	d_instantiate(dentry, inode);
+	dget(dentry);
+	inc_nlink(dentry->d_parent->d_inode);
+	fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
+	return end_creating(dentry, 0);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_dir);
 
@@ -419,25 +412,26 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 				      const char *target)
 {
 	struct dentry *dentry;
-	char *link;
-	int error;
-
-	link = kstrdup(target, GFP_KERNEL);
+	struct inode *inode;
+	char *link = kstrdup(target, GFP_KERNEL);
 	if (!link)
 		return NULL;
 
 	dentry = start_creating(name, parent);
-
 	if (IS_ERR(dentry)) {
 		kfree(link);
 		return NULL;
 	}
 
-	error = debugfs_mknod(dentry, S_IFLNK | S_IRWXUGO, link, NULL);
-	if (error)
+	inode = debugfs_get_inode(dentry->d_sb, S_IFLNK | S_IRWXUGO, 0,
+				  link, NULL);
+	if (unlikely(!inode)) {
 		kfree(link);
-
-	return end_creating(dentry, error);
+		return end_creating(dentry, -ENOMEM);
+	}
+	d_instantiate(dentry, inode);
+	dget(dentry);
+	return end_creating(dentry, 0);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_symlink);
 
-- 
cgit v0.10.2


From edac65eaf8d5c00b1d6004a44e76b9de6b038dc6 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 14:36:18 -0500
Subject: debugfs: take mode-dependent parts of debugfs_get_inode() into
 callers

... and trim the arguments list

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index b765c04..61e9a68 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -34,37 +34,12 @@ static struct vfsmount *debugfs_mount;
 static int debugfs_mount_count;
 static bool debugfs_registered;
 
-static struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev_t dev,
-				       void *data, const struct file_operations *fops)
-
+static struct inode *debugfs_get_inode(struct super_block *sb)
 {
 	struct inode *inode = new_inode(sb);
-
 	if (inode) {
 		inode->i_ino = get_next_ino();
-		inode->i_mode = mode;
 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
-		switch (mode & S_IFMT) {
-		default:
-			init_special_inode(inode, mode, dev);
-			break;
-		case S_IFREG:
-			inode->i_fop = fops ? fops : &debugfs_file_operations;
-			inode->i_private = data;
-			break;
-		case S_IFLNK:
-			inode->i_op = &debugfs_link_operations;
-			inode->i_private = data;
-			break;
-		case S_IFDIR:
-			inode->i_op = &simple_dir_inode_operations;
-			inode->i_fop = &simple_dir_operations;
-
-			/* directory inodes start off with i_nlink == 2
-			 * (for "." entry) */
-			inc_nlink(inode);
-			break;
-		}
 	}
 	return inode;
 }
@@ -334,10 +309,13 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 	if (IS_ERR(dentry))
 		return NULL;
 
-	inode = debugfs_get_inode(dentry->d_sb, mode, 0, data, fops);
+	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode))
 		return end_creating(dentry, -ENOMEM);
 
+	inode->i_mode = mode;
+	inode->i_fop = fops ? fops : &debugfs_file_operations;
+	inode->i_private = data;
 	d_instantiate(dentry, inode);
 	dget(dentry);
 	fsnotify_create(dentry->d_parent->d_inode, dentry);
@@ -371,12 +349,16 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 	if (IS_ERR(dentry))
 		return NULL;
 
-	inode = debugfs_get_inode(dentry->d_sb,
-				  S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
-				  0, NULL, NULL);
+	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode))
 		return end_creating(dentry, -ENOMEM);
 
+	inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
+	inode->i_op = &simple_dir_inode_operations;
+	inode->i_fop = &simple_dir_operations;
+
+	/* directory inodes start off with i_nlink == 2 (for "." entry) */
+	inc_nlink(inode);
 	d_instantiate(dentry, inode);
 	dget(dentry);
 	inc_nlink(dentry->d_parent->d_inode);
@@ -423,12 +405,14 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 		return NULL;
 	}
 
-	inode = debugfs_get_inode(dentry->d_sb, S_IFLNK | S_IRWXUGO, 0,
-				  link, NULL);
+	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode)) {
 		kfree(link);
 		return end_creating(dentry, -ENOMEM);
 	}
+	inode->i_mode = S_IFLNK | S_IRWXUGO;
+	inode->i_op = &debugfs_link_operations;
+	inode->i_private = link;
 	d_instantiate(dentry, inode);
 	dget(dentry);
 	return end_creating(dentry, 0);
-- 
cgit v0.10.2


From 5233e31191af661389a4f5b060873bfcb155c828 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 14:39:49 -0500
Subject: debugfs: split end_creating() into success and failure cases

... and don't bother with dput(dentry) in the former and with
dget(dentry) preceding all its calls.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 61e9a68..1219dff 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -256,15 +256,17 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
 	return dentry;
 }
 
-static struct dentry *end_creating(struct dentry *dentry, int error)
+static struct dentry *failed_creating(struct dentry *dentry)
 {
 	mutex_unlock(&dentry->d_parent->d_inode->i_mutex);
 	dput(dentry);
+	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+	return NULL;
+}
 
-	if (error) {
-		dentry = NULL;
-		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
-	}
+static struct dentry *end_creating(struct dentry *dentry)
+{
+	mutex_unlock(&dentry->d_parent->d_inode->i_mutex);
 	return dentry;
 }
 
@@ -311,15 +313,14 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 
 	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode))
-		return end_creating(dentry, -ENOMEM);
+		return failed_creating(dentry);
 
 	inode->i_mode = mode;
 	inode->i_fop = fops ? fops : &debugfs_file_operations;
 	inode->i_private = data;
 	d_instantiate(dentry, inode);
-	dget(dentry);
 	fsnotify_create(dentry->d_parent->d_inode, dentry);
-	return end_creating(dentry, 0);
+	return end_creating(dentry);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file);
 
@@ -351,7 +352,7 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 
 	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode))
-		return end_creating(dentry, -ENOMEM);
+		return failed_creating(dentry);
 
 	inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
 	inode->i_op = &simple_dir_inode_operations;
@@ -360,10 +361,9 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
 	d_instantiate(dentry, inode);
-	dget(dentry);
 	inc_nlink(dentry->d_parent->d_inode);
 	fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
-	return end_creating(dentry, 0);
+	return end_creating(dentry);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_dir);
 
@@ -408,14 +408,13 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 	inode = debugfs_get_inode(dentry->d_sb);
 	if (unlikely(!inode)) {
 		kfree(link);
-		return end_creating(dentry, -ENOMEM);
+		return failed_creating(dentry);
 	}
 	inode->i_mode = S_IFLNK | S_IRWXUGO;
 	inode->i_op = &debugfs_link_operations;
 	inode->i_private = link;
 	d_instantiate(dentry, inode);
-	dget(dentry);
-	return end_creating(dentry, 0);
+	return end_creating(dentry);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_symlink);
 
-- 
cgit v0.10.2


From 77b3da6e3232d3b4d4b8addb4b05799fe98f3bf8 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jan 2015 15:10:32 -0500
Subject: new primitive: debugfs_create_automount()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 1219dff..957c40c 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -175,6 +175,18 @@ static const struct super_operations debugfs_super_operations = {
 	.show_options	= debugfs_show_options,
 };
 
+static struct vfsmount *debugfs_automount(struct path *path)
+{
+	struct vfsmount *(*f)(void *);
+	f = (struct vfsmount *(*)(void *))path->dentry->d_fsdata;
+	return f(path->dentry->d_inode->i_private);
+}
+
+static const struct dentry_operations debugfs_dops = {
+	.d_delete = always_delete_dentry,
+	.d_automount = debugfs_automount,
+};
+
 static int debug_fill_super(struct super_block *sb, void *data, int silent)
 {
 	static struct tree_descr debug_files[] = {{""}};
@@ -199,6 +211,7 @@ static int debug_fill_super(struct super_block *sb, void *data, int silent)
 		goto fail;
 
 	sb->s_op = &debugfs_super_operations;
+	sb->s_d_op = &debugfs_dops;
 
 	debugfs_apply_options(sb);
 
@@ -368,6 +381,41 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 EXPORT_SYMBOL_GPL(debugfs_create_dir);
 
 /**
+ * debugfs_create_automount - create automount point in the debugfs filesystem
+ * @name: a pointer to a string containing the name of the file to create.
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @f: function to be called when pathname resolution steps on that one.
+ * @data: opaque argument to pass to f().
+ *
+ * @f should return what ->d_automount() would.
+ */
+struct dentry *debugfs_create_automount(const char *name,
+					struct dentry *parent,
+					struct vfsmount *(*f)(void *),
+					void *data)
+{
+	struct dentry *dentry = start_creating(name, parent);
+	struct inode *inode;
+
+	if (IS_ERR(dentry))
+		return NULL;
+
+	inode = debugfs_get_inode(dentry->d_sb);
+	if (unlikely(!inode))
+		return failed_creating(dentry);
+
+	inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
+	inode->i_flags |= S_AUTOMOUNT;
+	inode->i_private = data;
+	dentry->d_fsdata = (void *)f;
+	d_instantiate(dentry, inode);
+	return end_creating(dentry);
+}
+EXPORT_SYMBOL(debugfs_create_automount);
+
+/**
  * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
  * @name: a pointer to a string containing the name of the symbolic link to
  *        create.
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index da4c498..ea149a2 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -56,6 +56,11 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent);
 struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 				      const char *dest);
 
+struct dentry *debugfs_create_automount(const char *name,
+					struct dentry *parent,
+					struct vfsmount *(*f)(void *),
+					void *data);
+
 void debugfs_remove(struct dentry *dentry);
 void debugfs_remove_recursive(struct dentry *dentry);
 
-- 
cgit v0.10.2


From e59b4e9187bd5175b9845dc10fedb0879b7efbfd Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 21 Jan 2015 20:03:40 +0000
Subject: debugfs: Provide a file creation function that also takes an initial
 size

Provide a file creation function that also takes an initial size so that the
caller doesn't have to set i_size, thus meaning that we don't have to call
deal with ->d_inode in the callers.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/drivers/infiniband/hw/cxgb4/device.c b/drivers/infiniband/hw/cxgb4/device.c
index eb5df4e..391309a 100644
--- a/drivers/infiniband/hw/cxgb4/device.c
+++ b/drivers/infiniband/hw/cxgb4/device.c
@@ -700,37 +700,24 @@ static const struct file_operations ep_debugfs_fops = {
 
 static int setup_debugfs(struct c4iw_dev *devp)
 {
-	struct dentry *de;
-
 	if (!devp->debugfs_root)
 		return -1;
 
-	de = debugfs_create_file("qps", S_IWUSR, devp->debugfs_root,
-				 (void *)devp, &qp_debugfs_fops);
-	if (de && de->d_inode)
-		de->d_inode->i_size = 4096;
+	debugfs_create_file_size("qps", S_IWUSR, devp->debugfs_root,
+				 (void *)devp, &qp_debugfs_fops, 4096);
 
-	de = debugfs_create_file("stags", S_IWUSR, devp->debugfs_root,
-				 (void *)devp, &stag_debugfs_fops);
-	if (de && de->d_inode)
-		de->d_inode->i_size = 4096;
+	debugfs_create_file_size("stags", S_IWUSR, devp->debugfs_root,
+				 (void *)devp, &stag_debugfs_fops, 4096);
 
-	de = debugfs_create_file("stats", S_IWUSR, devp->debugfs_root,
-			(void *)devp, &stats_debugfs_fops);
-	if (de && de->d_inode)
-		de->d_inode->i_size = 4096;
+	debugfs_create_file_size("stats", S_IWUSR, devp->debugfs_root,
+				 (void *)devp, &stats_debugfs_fops, 4096);
 
-	de = debugfs_create_file("eps", S_IWUSR, devp->debugfs_root,
-			(void *)devp, &ep_debugfs_fops);
-	if (de && de->d_inode)
-		de->d_inode->i_size = 4096;
+	debugfs_create_file_size("eps", S_IWUSR, devp->debugfs_root,
+				 (void *)devp, &ep_debugfs_fops, 4096);
 
-	if (c4iw_wr_log) {
-		de = debugfs_create_file("wr_log", S_IWUSR, devp->debugfs_root,
-					 (void *)devp, &wr_log_debugfs_fops);
-		if (de && de->d_inode)
-			de->d_inode->i_size = 4096;
-	}
+	if (c4iw_wr_log)
+		debugfs_create_file_size("wr_log", S_IWUSR, devp->debugfs_root,
+					 (void *)devp, &wr_log_debugfs_fops, 4096);
 	return 0;
 }
 
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
index c98a350..4c7fe44 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
@@ -91,12 +91,9 @@ static const struct file_operations mem_debugfs_fops = {
 static void add_debugfs_mem(struct adapter *adap, const char *name,
 			    unsigned int idx, unsigned int size_mb)
 {
-	struct dentry *de;
-
-	de = debugfs_create_file(name, S_IRUSR, adap->debugfs_root,
-				 (void *)adap + idx, &mem_debugfs_fops);
-	if (de && de->d_inode)
-		de->d_inode->i_size = size_mb << 20;
+	debugfs_create_file_size(name, S_IRUSR, adap->debugfs_root,
+				 (void *)adap + idx, &mem_debugfs_fops,
+				 size_mb << 20);
 }
 
 /* Add an array of Debug FS files.
diff --git a/drivers/scsi/csiostor/csio_init.c b/drivers/scsi/csiostor/csio_init.c
index 34d20cc..2617f15 100644
--- a/drivers/scsi/csiostor/csio_init.c
+++ b/drivers/scsi/csiostor/csio_init.c
@@ -113,12 +113,9 @@ static const struct file_operations csio_mem_debugfs_fops = {
 void csio_add_debugfs_mem(struct csio_hw *hw, const char *name,
 				 unsigned int idx, unsigned int size_mb)
 {
-	struct dentry *de;
-
-	de = debugfs_create_file(name, S_IRUSR, hw->debugfs_root,
-				 (void *)hw + idx, &csio_mem_debugfs_fops);
-	if (de && de->d_inode)
-		de->d_inode->i_size = size_mb << 20;
+	debugfs_create_file_size(name, S_IRUSR, hw->debugfs_root,
+				 (void *)hw + idx, &csio_mem_debugfs_fops,
+				 size_mb << 20);
 }
 
 static int csio_setup_debugfs(struct csio_hw *hw)
diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
index 9f93bed..b2239a2 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.c
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
@@ -264,14 +264,17 @@ static void usba_init_debugfs(struct usba_udc *udc)
 		goto err_root;
 	udc->debugfs_root = root;
 
-	regs = debugfs_create_file("regs", 0400, root, udc, &regs_dbg_fops);
-	if (!regs)
-		goto err_regs;
-
 	regs_resource = platform_get_resource(udc->pdev, IORESOURCE_MEM,
 				CTRL_IOMEM_ID);
-	regs->d_inode->i_size = resource_size(regs_resource);
-	udc->debugfs_regs = regs;
+
+	if (regs_resource) {
+		regs = debugfs_create_file_size("regs", 0400, root, udc,
+						&regs_dbg_fops,
+						resource_size(regs_resource));
+		if (!regs)
+			goto err_regs;
+		udc->debugfs_regs = regs;
+	}
 
 	usba_ep_init_debugfs(udc, to_usba_ep(udc->gadget.ep0));
 
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 957c40c..45b18a5 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -338,6 +338,46 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 EXPORT_SYMBOL_GPL(debugfs_create_file);
 
 /**
+ * debugfs_create_file_size - create a file in the debugfs filesystem
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have.
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @data: a pointer to something that the caller will want to get to later
+ *        on.  The inode.i_private pointer will point to this value on
+ *        the open() call.
+ * @fops: a pointer to a struct file_operations that should be used for
+ *        this file.
+ * @file_size: initial file size
+ *
+ * This is the basic "create a file" function for debugfs.  It allows for a
+ * wide range of flexibility in creating a file, or a directory (if you want
+ * to create a directory, the debugfs_create_dir() function is
+ * recommended to be used instead.)
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.
+ */
+struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
+					struct dentry *parent, void *data,
+					const struct file_operations *fops,
+					loff_t file_size)
+{
+	struct dentry *de = debugfs_create_file(name, mode, parent, data, fops);
+
+	if (de)
+		de->d_inode->i_size = file_size;
+	return de;
+}
+EXPORT_SYMBOL_GPL(debugfs_create_file_size);
+
+/**
  * debugfs_create_dir - create a directory in the debugfs filesystem
  * @name: a pointer to a string containing the name of the directory to
  *        create.
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index ea149a2..cb25af4 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -51,6 +51,11 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 				   struct dentry *parent, void *data,
 				   const struct file_operations *fops);
 
+struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
+					struct dentry *parent, void *data,
+					const struct file_operations *fops,
+					loff_t file_size);
+
 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent);
 
 struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
@@ -129,6 +134,14 @@ static inline struct dentry *debugfs_create_file(const char *name, umode_t mode,
 	return ERR_PTR(-ENODEV);
 }
 
+static inline struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
+					struct dentry *parent, void *data,
+					const struct file_operations *fops,
+					loff_t file_size)
+{
+	return ERR_PTR(-ENODEV);
+}
+
 static inline struct dentry *debugfs_create_dir(const char *name,
 						struct dentry *parent)
 {
-- 
cgit v0.10.2