summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorNicolai Stange <nicstange@gmail.com>2017-10-31 02:15:52 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-07 22:25:02 +0300
commitc9afbec27089cd6b4e621b639f41c7fc726c3bf1 (patch)
treebb66d582f6668101cdbca5e6a3592f2398271443
parent7cda7b8f97da9382bb945d541a85cde58d5dac27 (diff)
downloadlinux-c9afbec27089cd6b4e621b639f41c7fc726c3bf1.tar.xz
debugfs: purge obsolete SRCU based removal protection
Purge the SRCU based file removal race protection in favour of the new, refcount based debugfs_file_get()/debugfs_file_put() API. Fixes: 49d200deaa68 ("debugfs: prevent access to removed files' private data") Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/debugfs/file.c48
-rw-r--r--fs/debugfs/inode.c7
-rw-r--r--include/linux/debugfs.h19
-rw-r--r--lib/Kconfig.debug1
4 files changed, 0 insertions, 75 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index d3a972b45ff0..53f5c9a2af88 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -22,7 +22,6 @@
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/device.h>
-#include <linux/srcu.h>
#include <asm/poll.h>
#include "internal.h"
@@ -48,53 +47,6 @@ const struct file_operations debugfs_noop_file_operations = {
.llseek = noop_llseek,
};
-/**
- * debugfs_use_file_start - mark the beginning of file data access
- * @dentry: the dentry object whose data is being accessed.
- * @srcu_idx: a pointer to some memory to store a SRCU index in.
- *
- * Up to a matching call to debugfs_use_file_finish(), any
- * successive call into the file removing functions debugfs_remove()
- * and debugfs_remove_recursive() will block. Since associated private
- * file data may only get freed after a successful return of any of
- * the removal functions, you may safely access it after a successful
- * call to debugfs_use_file_start() without worrying about
- * lifetime issues.
- *
- * If -%EIO is returned, the file has already been removed and thus,
- * it is not safe to access any of its data. If, on the other hand,
- * it is allowed to access the file data, zero is returned.
- *
- * Regardless of the return code, any call to
- * debugfs_use_file_start() must be followed by a matching call
- * to debugfs_use_file_finish().
- */
-int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx)
- __acquires(&debugfs_srcu)
-{
- *srcu_idx = srcu_read_lock(&debugfs_srcu);
- barrier();
- if (d_unlinked(dentry))
- return -EIO;
- return 0;
-}
-EXPORT_SYMBOL_GPL(debugfs_use_file_start);
-
-/**
- * debugfs_use_file_finish - mark the end of file data access
- * @srcu_idx: the SRCU index "created" by a former call to
- * debugfs_use_file_start().
- *
- * Allow any ongoing concurrent call into debugfs_remove() or
- * debugfs_remove_recursive() blocked by a former call to
- * debugfs_use_file_start() to proceed and return to its caller.
- */
-void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu)
-{
- srcu_read_unlock(&debugfs_srcu, srcu_idx);
-}
-EXPORT_SYMBOL_GPL(debugfs_use_file_finish);
-
#define F_DENTRY(filp) ((filp)->f_path.dentry)
const struct file_operations *debugfs_real_fops(const struct file *filp)
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 6449eb935540..f587aded46b5 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -27,14 +27,11 @@
#include <linux/parser.h>
#include <linux/magic.h>
#include <linux/slab.h>
-#include <linux/srcu.h>
#include "internal.h"
#define DEBUGFS_DEFAULT_MODE 0700
-DEFINE_SRCU(debugfs_srcu);
-
static struct vfsmount *debugfs_mount;
static int debugfs_mount_count;
static bool debugfs_registered;
@@ -693,8 +690,6 @@ void debugfs_remove(struct dentry *dentry)
inode_unlock(d_inode(parent));
if (!ret)
simple_release_fs(&debugfs_mount, &debugfs_mount_count);
-
- synchronize_srcu(&debugfs_srcu);
}
EXPORT_SYMBOL_GPL(debugfs_remove);
@@ -768,8 +763,6 @@ void debugfs_remove_recursive(struct dentry *dentry)
if (!__debugfs_remove(child, parent))
simple_release_fs(&debugfs_mount, &debugfs_mount_count);
inode_unlock(d_inode(parent));
-
- synchronize_srcu(&debugfs_srcu);
}
EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index c5eda259b9d6..9f821a43bb0d 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -23,7 +23,6 @@
struct device;
struct file_operations;
-struct srcu_struct;
struct debugfs_blob_wrapper {
void *data;
@@ -43,8 +42,6 @@ struct debugfs_regset32 {
extern struct dentry *arch_debugfs_dir;
-extern struct srcu_struct debugfs_srcu;
-
#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt) \
static int __fops ## _open(struct inode *inode, struct file *file) \
{ \
@@ -90,11 +87,6 @@ struct dentry *debugfs_create_automount(const char *name,
void debugfs_remove(struct dentry *dentry);
void debugfs_remove_recursive(struct dentry *dentry);
-int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx)
- __acquires(&debugfs_srcu);
-
-void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu);
-
const struct file_operations *debugfs_real_fops(const struct file *filp);
int debugfs_file_get(struct dentry *dentry);
@@ -227,17 +219,6 @@ static inline void debugfs_remove(struct dentry *dentry)
static inline void debugfs_remove_recursive(struct dentry *dentry)
{ }
-static inline int debugfs_use_file_start(const struct dentry *dentry,
- int *srcu_idx)
- __acquires(&debugfs_srcu)
-{
- return 0;
-}
-
-static inline void debugfs_use_file_finish(int srcu_idx)
- __releases(&debugfs_srcu)
-{ }
-
static inline int debugfs_file_get(struct dentry *dentry)
{
return 0;
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index dfdad67d8f6c..57fb43f521c3 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -280,7 +280,6 @@ config PAGE_OWNER
config DEBUG_FS
bool "Debug Filesystem"
- select SRCU
help
debugfs is a virtual file system that kernel developers use to put
debugging files into. Enable this option to be able to read and