From 86f0e06767dda7863d6d2a8f0b3b857e6ea876a0 Mon Sep 17 00:00:00 2001 From: Christian Lamparter Date: Sat, 17 Sep 2016 21:43:01 +0200 Subject: debugfs: introduce a public file_operations accessor This patch introduces an accessor which can be used by the users of debugfs (drivers, fs, ...) to get the original file_operations struct. It also removes the REAL_FOPS_DEREF macro in file.c and converts the code to use the public version. Previously, REAL_FOPS_DEREF was only available within the file.c of debugfs. But having a public getter available for debugfs users is important as some drivers (carl9170 and b43) use the pointer of the original file_operations in conjunction with container_of() within their debugfs implementations. Reviewed-by: Nicolai Stange Signed-off-by: Christian Lamparter Cc: stable # 4.7+ Signed-off-by: Greg Kroah-Hartman --- include/linux/debugfs.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include/linux/debugfs.h') diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index 1438e2322d5c..4d3f0d1aec73 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -45,6 +45,23 @@ extern struct dentry *arch_debugfs_dir; extern struct srcu_struct debugfs_srcu; +/** + * debugfs_real_fops - getter for the real file operation + * @filp: a pointer to a struct file + * + * Must only be called under the protection established by + * debugfs_use_file_start(). + */ +static inline const struct file_operations *debugfs_real_fops(struct file *filp) + __must_hold(&debugfs_srcu) +{ + /* + * Neither the pointer to the struct file_operations, nor its + * contents ever change -- srcu_dereference() is not needed here. + */ + return filp->f_path.dentry->d_fsdata; +} + #if defined(CONFIG_DEBUG_FS) struct dentry *debugfs_create_file(const char *name, umode_t mode, -- cgit