[PATCH] kernel: exit: cleanup release_thread()

* [PATCH] kernel: exit: cleanup release_thread()
@ 2022-08-19  1:44 Kefeng Wang
  2022-08-19  1:47 ` Guo Ren
                   ` (5 more replies)
  0 siblings, 6 replies; 8+ messages in thread
From: Kefeng Wang @ 2022-08-19  1:44 UTC (permalink / raw)
  To: Richard Henderson, Ivan Kokshaysky, Matt Turner, Vineet Gupta,
	Russell King, Catalin Marinas, Will Deacon, Guo Ren, Brian Cain,
	Huacai Chen, WANG Xuerui, Geert Uytterhoeven, Michal Simek,
	Thomas Bogendoerfer, Dinh Nguyen, Jonas Bonn,
	Stefan Kristiansson, Stafford Horne, James E . J . Bottomley,
	Helge Deller, Michael Ellerman, Nicholas Piggin,
	Christophe Leroy, Paul Walmsley, Palmer Dabbelt, Heiko Carstens,
	Vasily Gorbik, Alexander Gordeev, Christian Borntraeger,
	Sven Schnelle, Yoshinori Sato, Rich Felker, David S . Miller,
	Richard Weinberger, Anton Ivanov, Johannes Berg, Thomas Gleixner,
	Ingo Molnar, Borislav Petkov, Dave Hansen, x86, Chris Zankel,
	Max Filippov, linux-alpha, linux-kernel, linux-snps-arc,
	linux-arm-kernel, linux-csky, linux-hexagon, linux-ia64,
	loongarch, linux-m68k, linux-mips, openrisc, linux-parisc,
	linuxppc-dev, linux-riscv, linux-s390, linux-sh, sparclinux,
	linux-um, linux-xtensa, akpm
  Cc: Kefeng Wang

Only x86 has own release_thread(), introduce a new weak
release_thread() function to clean empty definitions in
other ARCHs.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 arch/alpha/include/asm/processor.h      | 2 --
 arch/alpha/kernel/process.c             | 5 -----
 arch/arc/include/asm/processor.h        | 3 ---
 arch/arm/include/asm/processor.h        | 3 ---
 arch/arm/kernel/process.c               | 4 ----
 arch/arm64/include/asm/processor.h      | 3 ---
 arch/arm64/kernel/process.c             | 4 ----
 arch/csky/include/asm/processor.h       | 5 -----
 arch/hexagon/include/asm/processor.h    | 4 ----
 arch/hexagon/kernel/process.c           | 7 -------
 arch/ia64/include/asm/processor.h       | 7 -------
 arch/loongarch/include/asm/processor.h  | 3 ---
 arch/m68k/include/asm/processor.h       | 5 -----
 arch/microblaze/include/asm/processor.h | 5 -----
 arch/mips/include/asm/processor.h       | 3 ---
 arch/nios2/include/asm/processor.h      | 5 -----
 arch/openrisc/include/asm/processor.h   | 1 -
 arch/openrisc/kernel/process.c          | 4 ----
 arch/parisc/include/asm/processor.h     | 3 ---
 arch/parisc/kernel/process.c            | 4 ----
 arch/powerpc/include/asm/processor.h    | 1 -
 arch/powerpc/kernel/process.c           | 5 -----
 arch/riscv/include/asm/processor.h      | 5 -----
 arch/s390/include/asm/processor.h       | 3 ---
 arch/sh/include/asm/processor_32.h      | 3 ---
 arch/sh/kernel/process_32.c             | 5 -----
 arch/sparc/include/asm/processor_32.h   | 3 ---
 arch/sparc/include/asm/processor_64.h   | 3 ---
 arch/um/include/asm/processor-generic.h | 4 ----
 arch/x86/include/asm/processor.h        | 3 ---
 arch/xtensa/include/asm/processor.h     | 3 ---
 include/linux/sched/task.h              | 3 +++
 kernel/exit.c                           | 4 ++++
 33 files changed, 7 insertions(+), 118 deletions(-)

diff --git a/arch/alpha/include/asm/processor.h b/arch/alpha/include/asm/processor.h
index 43e234c518b1..714abe494e5f 100644
--- a/arch/alpha/include/asm/processor.h
+++ b/arch/alpha/include/asm/processor.h
@@ -36,8 +36,6 @@ extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
 
 /* Free all resources held by a thread. */
 struct task_struct;
-extern void release_thread(struct task_struct *);
-
 unsigned long __get_wchan(struct task_struct *p);
 
 #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
index e2e25f8b5e76..dbf1bc5e2ad2 100644
--- a/arch/alpha/kernel/process.c
+++ b/arch/alpha/kernel/process.c
@@ -225,11 +225,6 @@ flush_thread(void)
 	current_thread_info()->pcb.unique = 0;
 }
 
-void
-release_thread(struct task_struct *dead_task)
-{
-}
-
 /*
  * Copy architecture-specific thread state
  */
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 54db9d7bb562..fb844fce1ab6 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -43,9 +43,6 @@ struct task_struct;
 #define task_pt_regs(p) \
 	((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1)
 
-/* Free all resources held by a thread */
-#define release_thread(thread) do { } while (0)
-
 /*
  * A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
  * get optimised away by gcc
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index bdc35c0e8dfb..326864f79d18 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -81,9 +81,6 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset,
 /* Forward declaration, a strange C thing */
 struct task_struct;
 
-/* Free all resources held by a thread. */
-extern void release_thread(struct task_struct *);
-
 unsigned long __get_wchan(struct task_struct *p);
 
 #define task_pt_regs(p) \
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 3d9cace63884..712d3e6d9be9 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -232,10 +232,6 @@ void flush_thread(void)
 	thread_notify(THREAD_NOTIFY_FLUSH, thread);
 }
 
-void release_thread(struct task_struct *dead_task)
-{
-}
-
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 86eb0bfe3b38..4cfb4cd1d475 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -323,9 +323,6 @@ static inline bool is_ttbr1_addr(unsigned long addr)
 /* Forward declaration, a strange C thing */
 struct task_struct;
 
-/* Free all resources held by a thread. */
-extern void release_thread(struct task_struct *);
-
 unsigned long __get_wchan(struct task_struct *p);
 
 void update_sctlr_el1(u64 sctlr);
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 92bcc1768f0b..9015f49c206e 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -279,10 +279,6 @@ void flush_thread(void)
 	flush_tagged_addr_state();
 }
 
-void release_thread(struct task_struct *dead_task)
-{
-}
-
 void arch_release_task_struct(struct task_struct *tsk)
 {
 	fpsimd_release_task(tsk);
diff --git a/arch/csky/include/asm/processor.h b/arch/csky/include/asm/processor.h
index 9638206bc44f..63ad71fab30d 100644
--- a/arch/csky/include/asm/processor.h
+++ b/arch/csky/include/asm/processor.h
@@ -69,11 +69,6 @@ do {									\
 /* Forward declaration, a strange C thing */
 struct task_struct;
 
-/* Free all resources held by a thread. */
-static inline void release_thread(struct task_struct *dead_task)
-{
-}
-
 /* Prepare to copy thread state - unlazy all lazy status */
 #define prepare_to_copy(tsk)    do { } while (0)
 
diff --git a/arch/hexagon/include/asm/processor.h b/arch/hexagon/include/asm/processor.h
index 615f7e49968e..0cd39c2cdf8f 100644
--- a/arch/hexagon/include/asm/processor.h
+++ b/arch/hexagon/include/asm/processor.h
@@ -60,10 +60,6 @@ struct thread_struct {
 #define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
 #define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
 
-/*  Free all resources held by a thread; defined in process.c  */
-extern void release_thread(struct task_struct *dead_task);
-
-/* Get wait channel for task P.  */
 extern unsigned long __get_wchan(struct task_struct *p);
 
 /*  The following stuff is pretty HEXAGON specific.  */
diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c
index f0552f98a7ba..e15eeaebd785 100644
--- a/arch/hexagon/kernel/process.c
+++ b/arch/hexagon/kernel/process.c
@@ -112,13 +112,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 	return 0;
 }
 
-/*
- * Release any architecture-specific resources locked by thread
- */
-void release_thread(struct task_struct *dead_task)
-{
-}
-
 /*
  * Some archs flush debug and FPU info here
  */
diff --git a/arch/ia64/include/asm/processor.h b/arch/ia64/include/asm/processor.h
index 757c2f6d8d4b..d1978e004054 100644
--- a/arch/ia64/include/asm/processor.h
+++ b/arch/ia64/include/asm/processor.h
@@ -318,13 +318,6 @@ struct thread_struct {
 struct mm_struct;
 struct task_struct;
 
-/*
- * Free all resources held by a thread. This is called after the
- * parent of DEAD_TASK has collected the exit status of the task via
- * wait().
- */
-#define release_thread(dead_task)
-
 /* Get wait channel for task P.  */
 extern unsigned long __get_wchan (struct task_struct *p);
 
diff --git a/arch/loongarch/include/asm/processor.h b/arch/loongarch/include/asm/processor.h
index 1c4b4308378d..6954dc5d24e9 100644
--- a/arch/loongarch/include/asm/processor.h
+++ b/arch/loongarch/include/asm/processor.h
@@ -176,9 +176,6 @@ struct thread_struct {
 
 struct task_struct;
 
-/* Free all resources held by a thread. */
-#define release_thread(thread) do { } while (0)
-
 enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_HALT, IDLE_NOMWAIT, IDLE_POLL};
 
 extern unsigned long		boot_option_idle_override;
diff --git a/arch/m68k/include/asm/processor.h b/arch/m68k/include/asm/processor.h
index d86b4009880b..7a2da780830b 100644
--- a/arch/m68k/include/asm/processor.h
+++ b/arch/m68k/include/asm/processor.h
@@ -145,11 +145,6 @@ static inline void start_thread(struct pt_regs * regs, unsigned long pc,
 /* Forward declaration, a strange C thing */
 struct task_struct;
 
-/* Free all resources held by a thread. */
-static inline void release_thread(struct task_struct *dead_task)
-{
-}
-
 unsigned long __get_wchan(struct task_struct *p);
 void show_registers(struct pt_regs *regs);
 
diff --git a/arch/microblaze/include/asm/processor.h b/arch/microblaze/include/asm/processor.h
index 7e9e92670df3..4e193c7550df 100644
--- a/arch/microblaze/include/asm/processor.h
+++ b/arch/microblaze/include/asm/processor.h
@@ -63,11 +63,6 @@ struct thread_struct {
 	.pgdir = swapper_pg_dir, \
 }
 
-/* Free all resources held by a thread. */
-static inline void release_thread(struct task_struct *dead_task)
-{
-}
-
 unsigned long __get_wchan(struct task_struct *p);
 
 /* The size allocated for kernel stacks. This _must_ be a power of two! */
diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index 4bb24579d12e..3fde1ff72bd1 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -344,9 +344,6 @@ struct thread_struct {
 
 struct task_struct;
 
-/* Free all resources held by a thread. */
-#define release_thread(thread) do { } while(0)
-
 /*
  * Do necessary setup to start up a newly executed thread.
  */
diff --git a/arch/nios2/include/asm/processor.h b/arch/nios2/include/asm/processor.h
index b8125dfbcad2..8916d93d5c2d 100644
--- a/arch/nios2/include/asm/processor.h
+++ b/arch/nios2/include/asm/processor.h
@@ -64,11 +64,6 @@ extern void start_thread(struct pt_regs *regs, unsigned long pc,
 
 struct task_struct;
 
-/* Free all resources held by a thread. */
-static inline void release_thread(struct task_struct *dead_task)
-{
-}
-
 extern unsigned long __get_wchan(struct task_struct *p);
 
 #define task_pt_regs(p) \
diff --git a/arch/openrisc/include/asm/processor.h b/arch/openrisc/include/asm/processor.h
index aa1699c18add..ed9efb430afa 100644
--- a/arch/openrisc/include/asm/processor.h
+++ b/arch/openrisc/include/asm/processor.h
@@ -72,7 +72,6 @@ struct thread_struct {
 
 
 void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp);
-void release_thread(struct task_struct *);
 unsigned long __get_wchan(struct task_struct *p);
 
 #define cpu_relax()     barrier()
diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c
index 52dc983ddeba..f94b5ec06786 100644
--- a/arch/openrisc/kernel/process.c
+++ b/arch/openrisc/kernel/process.c
@@ -125,10 +125,6 @@ void show_regs(struct pt_regs *regs)
 	show_registers(regs);
 }
 
-void release_thread(struct task_struct *dead_task)
-{
-}
-
 /*
  * Copy the thread-specific (arch specific) info from the current
  * process to the new one p
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index 4621ceb51314..a608970b249a 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -266,9 +266,6 @@ on downward growing arches, it looks like this:
 
 struct mm_struct;
 
-/* Free all resources held by a thread. */
-extern void release_thread(struct task_struct *);
-
 extern unsigned long __get_wchan(struct task_struct *p);
 
 #define KSTK_EIP(tsk)	((tsk)->thread.regs.iaoq[0])
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index 7c37e09c92da..3db0e97e6c06 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -146,10 +146,6 @@ void flush_thread(void)
 	*/
 }
 
-void release_thread(struct task_struct *dead_task)
-{
-}
-
 /*
  * Idle thread support
  *
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index fdfaae194ddd..92e332415d02 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -75,7 +75,6 @@ extern int _chrp_type;
 
 struct task_struct;
 void start_thread(struct pt_regs *regs, unsigned long fdptr, unsigned long sp);
-void release_thread(struct task_struct *);
 
 #define TS_FPR(i) fp_state.fpr[i][TS_FPROFFSET]
 #define TS_CKFPR(i) ckfp_state.fpr[i][TS_FPROFFSET]
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 0fbda89cd1bb..991cda25b9a9 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1655,11 +1655,6 @@ EXPORT_SYMBOL_GPL(set_thread_tidr);
 
 #endif /* CONFIG_PPC64 */
 
-void
-release_thread(struct task_struct *t)
-{
-}
-
 /*
  * this gets called so that we can store coprocessor state into memory and
  * copy the current task into the new thread.
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 19eedd4af4cd..94a0590c6971 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -65,11 +65,6 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset,
 extern void start_thread(struct pt_regs *regs,
 			unsigned long pc, unsigned long sp);
 
-/* Free all resources held by a thread. */
-static inline void release_thread(struct task_struct *dead_task)
-{
-}
-
 extern unsigned long __get_wchan(struct task_struct *p);
 
 
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index bd66f8e34949..c52fe651eeba 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -186,9 +186,6 @@ struct pt_regs;
 void show_registers(struct pt_regs *regs);
 void show_cacheinfo(struct seq_file *m);
 
-/* Free all resources held by a thread. */
-static inline void release_thread(struct task_struct *tsk) { }
-
 /* Free guarded storage control block */
 void guarded_storage_release(struct task_struct *tsk);
 void gs_load_bc_cb(struct pt_regs *regs);
diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index 45240ec6b85a..27aebf1e75a2 100644
--- a/arch/sh/include/asm/processor_32.h
+++ b/arch/sh/include/asm/processor_32.h
@@ -127,9 +127,6 @@ struct task_struct;
 
 extern void start_thread(struct pt_regs *regs, unsigned long new_pc, unsigned long new_sp);
 
-/* Free all resources held by a thread. */
-extern void release_thread(struct task_struct *);
-
 /*
  * FPU lazy state save handling.
  */
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index a808843375e7..92b6649d4929 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -84,11 +84,6 @@ void flush_thread(void)
 #endif
 }
 
-void release_thread(struct task_struct *dead_task)
-{
-	/* do nothing */
-}
-
 asmlinkage void ret_from_fork(void);
 asmlinkage void ret_from_kernel_thread(void);
 
diff --git a/arch/sparc/include/asm/processor_32.h b/arch/sparc/include/asm/processor_32.h
index b26c35336b51..ba8b70ffec08 100644
--- a/arch/sparc/include/asm/processor_32.h
+++ b/arch/sparc/include/asm/processor_32.h
@@ -80,9 +80,6 @@ static inline void start_thread(struct pt_regs * regs, unsigned long pc,
 			     : "memory");
 }
 
-/* Free all resources held by a thread. */
-#define release_thread(tsk)		do { } while(0)
-
 unsigned long __get_wchan(struct task_struct *);
 
 #define task_pt_regs(tsk) ((tsk)->thread.kregs)
diff --git a/arch/sparc/include/asm/processor_64.h b/arch/sparc/include/asm/processor_64.h
index 89850dff6b03..2667f35d5ea5 100644
--- a/arch/sparc/include/asm/processor_64.h
+++ b/arch/sparc/include/asm/processor_64.h
@@ -176,9 +176,6 @@ do { \
 	regs->tstate &= ~TSTATE_PEF;	\
 } while (0)
 
-/* Free all resources held by a thread. */
-#define release_thread(tsk)		do { } while (0)
-
 unsigned long __get_wchan(struct task_struct *task);
 
 #define task_pt_regs(tsk) (task_thread_info(tsk)->kregs)
diff --git a/arch/um/include/asm/processor-generic.h b/arch/um/include/asm/processor-generic.h
index d0fc1862da95..bb5f06480da9 100644
--- a/arch/um/include/asm/processor-generic.h
+++ b/arch/um/include/asm/processor-generic.h
@@ -55,10 +55,6 @@ struct thread_struct {
 	.request		= { 0 } \
 }
 
-static inline void release_thread(struct task_struct *task)
-{
-}
-
 /*
  * User space process size: 3GB (default).
  */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 356308c73951..67c9d73b31fa 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -587,9 +587,6 @@ static inline void load_sp0(unsigned long sp0)
 
 #endif /* CONFIG_PARAVIRT_XXL */
 
-/* Free all resources held by a thread. */
-extern void release_thread(struct task_struct *);
-
 unsigned long __get_wchan(struct task_struct *p);
 
 /*
diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h
index 76bc63127c66..5abde43c570c 100644
--- a/arch/xtensa/include/asm/processor.h
+++ b/arch/xtensa/include/asm/processor.h
@@ -221,9 +221,6 @@ struct thread_struct {
 struct task_struct;
 struct mm_struct;
 
-/* Free all resources held by a thread. */
-#define release_thread(thread) do { } while(0)
-
 extern unsigned long __get_wchan(struct task_struct *p);
 
 #define KSTK_EIP(tsk)		(task_pt_regs(tsk)->pc)
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 81cab4b01edc..d6c48163c6de 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -127,6 +127,9 @@ static inline void put_task_struct_many(struct task_struct *t, int nr)
 
 void put_task_struct_rcu_user(struct task_struct *task);
 
+/* Free all architecture-specific resources held by a thread. */
+void release_thread(struct task_struct *dead_task);
+
 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
 extern int arch_task_struct_size __read_mostly;
 #else
diff --git a/kernel/exit.c b/kernel/exit.c
index 80376b4ac763..30cabf933fed 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -183,6 +183,10 @@ void put_task_struct_rcu_user(struct task_struct *task)
 		call_rcu(&task->rcu, delayed_put_task_struct);
 }
 
+void __weak release_thread(struct task_struct *dead_task)
+{
+}
+
 void release_task(struct task_struct *p)
 {
 	struct task_struct *leader;
-- 
2.35.3


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