debugfs: purge obsolete SRCU based removal protection (c9afbec2) · Commits · 戴 / test

fs/debugfs/file.c

+0 −48

Original line number	Diff line number	Diff line
		@@ -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)

fs/debugfs/inode.c

+0 −7

Original line number	Diff line number	Diff line
		@@ -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);

include/linux/debugfs.h

+0 −19

Original line number	Diff line number	Diff line
		@@ -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;

lib/Kconfig.debug

+0 −1

Original line number	Diff line number	Diff line
		@@ -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

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