VisionFive2 Linux kernel

StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)

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author: Nicolai Stange <nicstange@gmail.com> 2016-03-22 14:11:15 +0100 committer: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 2016-04-12 14:14:21 -0700 commit: c64688081490321f2d23a292ef24e60bb321f3f1 parent: 49d200deaa680501f19a247b1fffb29301e51d2b
Commit Summary:
debugfs: add support for self-protecting attribute file fops
Diffstat:
2 files changed, 53 insertions, 0 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 6eb58a8ed03c..8ef56d9499a4 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -284,6 +284,34 @@ const struct file_operations debugfs_full_proxy_file_operations = {
 	.open = full_proxy_open,
 };
 
+ssize_t debugfs_attr_read(struct file *file, char __user *buf,
+			size_t len, loff_t *ppos)
+{
+	ssize_t ret;
+	int srcu_idx;
+
+	ret = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);
+	if (likely(!ret))
+		ret = simple_attr_read(file, buf, len, ppos);
+	debugfs_use_file_finish(srcu_idx);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(debugfs_attr_read);
+
+ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
+			 size_t len, loff_t *ppos)
+{
+	ssize_t ret;
+	int srcu_idx;
+
+	ret = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);
+	if (likely(!ret))
+		ret = simple_attr_write(file, buf, len, ppos);
+	debugfs_use_file_finish(srcu_idx);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(debugfs_attr_write);
+
 static struct dentry *debugfs_create_mode(const char *name, umode_t mode,
 					  struct dentry *parent, void *value,
 				          const struct file_operations *fops,
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 136f269f01de..41e079a8da26 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -369,6 +369,33 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file);
 
+/**
+ * debugfs_create_file_unsafe - 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.
+ *
+ * debugfs_create_file_unsafe() is completely analogous to
+ * debugfs_create_file(), the only difference being that the fops
+ * handed it will not get protected against file removals by the
+ * debugfs core.
+ *
+ * It is your responsibility to protect your struct file_operation
+ * methods against file removals by means of debugfs_use_file_start()
+ * and debugfs_use_file_finish(). ->open() is still protected by
+ * debugfs though.
+ *
+ * Any struct file_operations defined by means of
+ * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and
+ * thus, may be used here.
+ */
 struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
 				   struct dentry *parent, void *data,
 				   const struct file_operations *fops)
@@ -379,6 +406,7 @@ struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
 					&debugfs_noop_file_operations,
 				fops);
 }
+EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe);
 
 /**
  * debugfs_create_file_size - create a file in the debugfs filesystem