[PATCH v2 3/4] exit_thread: accept a task parameter to be exited

From: Jiri Slaby
Date: Thu Mar 31 2016 - 03:56:38 EST

We need to call exit_thread from copy_process in a fail path. So make
it accept task_struct as a parameter.

[v2]
* s390: exit_thread_runtime_instr doesn't make sense to be called for
non-current tasks.
* arm: fix the comment in vfp_thread_copy
* change 'me' to 'tsk' for task_struct
* now we can change only archs that actually have exit_thread

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
Cc: Hans-Christian Egtvedt <egtvedt@xxxxxxxxxxxx>
Cc: Mikael Starvik <starvik@xxxxxxxx>
Cc: Jesper Nilsson <jesper.nilsson@xxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: James Hogan <james.hogan@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Koichi Yasutake <yasutake.koichi@xxxxxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-cris-kernel@xxxxxxxx
Cc: linux-ia64@xxxxxxxxxxxxxxx
Cc: linux-metag@xxxxxxxxxxxxxxx
Cc: linux-am33-list@xxxxxxxxxx
Cc: linux-s390@xxxxxxxxxxxxxxx
Cc: linux-sh@xxxxxxxxxxxxxxx
Cc: sparclinux@xxxxxxxxxxxxxxx
Cc: linux-xtensa@xxxxxxxxxxxxxxxx
---
arch/arm/kernel/process.c | 4 ++--
arch/arm/vfp/vfpmodule.c | 4 ----
arch/avr32/kernel/process.c | 4 ++--
arch/cris/arch-v32/kernel/process.c | 4 ++--
arch/ia64/kernel/perfmon.c | 4 ++--
arch/ia64/kernel/process.c | 14 +++++++-------
arch/metag/kernel/process.c | 6 +++---
arch/mn10300/kernel/process.c | 4 ++--
arch/s390/kernel/process.c | 5 +++--
arch/sh/kernel/process_64.c | 4 ++--
arch/sparc/kernel/process_32.c | 12 ++++++------
arch/sparc/kernel/process_64.c | 4 ++--
arch/tile/kernel/process.c | 4 ++--
arch/x86/kernel/process.c | 5 ++---
arch/xtensa/kernel/process.c | 4 ++--
include/linux/sched.h | 4 ++--
kernel/exit.c | 2 +-
17 files changed, 42 insertions(+), 46 deletions(-)

diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 4adfb46e3ee9..a647d6642f3e 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -193,9 +193,9 @@ EXPORT_SYMBOL_GPL(thread_notify_head);
/*
* Free current thread data structures etc..
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
- thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
+ thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
}

void flush_thread(void)
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 2a61e4b04600..73085d3482ed 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -156,10 +156,6 @@ static void vfp_thread_copy(struct thread_info *thread)
* - we could be preempted if tree preempt rcu is enabled, so
* it is unsafe to use thread->cpu.
* THREAD_NOTIFY_EXIT
- * - the thread (v) will be running on the local CPU, so
- * v === current_thread_info()
- * - thread->cpu is the local CPU number at the time it is accessed,
- * but may change at any time.
* - we could be preempted if tree preempt rcu is enabled, so
* it is unsafe to use thread->cpu.
*/
diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c
index 42a53e740a7e..68e5b9dac059 100644
--- a/arch/avr32/kernel/process.c
+++ b/arch/avr32/kernel/process.c
@@ -62,9 +62,9 @@ void machine_restart(char *cmd)
/*
* Free current thread data structures etc
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
- ocd_disable(current);
+ ocd_disable(tsk);
}

void flush_thread(void)
diff --git a/arch/cris/arch-v32/kernel/process.c b/arch/cris/arch-v32/kernel/process.c
index c7ce784a393c..4d1afa9f9fd3 100644
--- a/arch/cris/arch-v32/kernel/process.c
+++ b/arch/cris/arch-v32/kernel/process.c
@@ -33,9 +33,9 @@ void default_idle(void)
*/

extern void deconfigure_bp(long pid);
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
- deconfigure_bp(current->pid);
+ deconfigure_bp(tsk->pid);
}

/*
diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 9cd607b06964..2436ad5f92c1 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -4542,8 +4542,8 @@ pfm_context_unload(pfm_context_t *ctx, void *arg, int count, struct pt_regs *reg


/*
- * called only from exit_thread(): task == current
- * we come here only if current has a context attached (loaded or masked)
+ * called only from exit_thread()
+ * we come here only if the task has a context attached (loaded or masked)
*/
void
pfm_exit_thread(struct task_struct *task)
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index b51514957620..aae6c4dc7ae7 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -570,22 +570,22 @@ flush_thread (void)
}

/*
- * Clean up state associated with current thread. This is called when
+ * Clean up state associated with a thread. This is called when
* the thread calls exit().
*/
void
-exit_thread (void)
+exit_thread (struct task_struct *tsk)
{

- ia64_drop_fpu(current);
+ ia64_drop_fpu(tsk);
#ifdef CONFIG_PERFMON
/* if needed, stop monitoring and flush state to perfmon context */
- if (current->thread.pfm_context)
- pfm_exit_thread(current);
+ if (tsk->thread.pfm_context)
+ pfm_exit_thread(tsk);

/* free debug register resources */
- if (current->thread.flags & IA64_THREAD_DBG_VALID)
- pfm_release_debug_registers(current);
+ if (tsk->thread.flags & IA64_THREAD_DBG_VALID)
+ pfm_release_debug_registers(tsk);
#endif
}

diff --git a/arch/metag/kernel/process.c b/arch/metag/kernel/process.c
index 7f546183a0f0..35062796edf2 100644
--- a/arch/metag/kernel/process.c
+++ b/arch/metag/kernel/process.c
@@ -345,10 +345,10 @@ void flush_thread(void)
/*
* Free current thread data structures etc.
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
- clear_fpu(&current->thread);
- clear_dsp(&current->thread);
+ clear_fpu(&tsk->thread);
+ clear_dsp(&tsk->thread);
}

/* TODO: figure out how to unwind the kernel stack here to figure out
diff --git a/arch/mn10300/kernel/process.c b/arch/mn10300/kernel/process.c
index 74a96ccf7451..cbede4e88dee 100644
--- a/arch/mn10300/kernel/process.c
+++ b/arch/mn10300/kernel/process.c
@@ -103,9 +103,9 @@ void show_regs(struct pt_regs *regs)
/*
* free current thread data structures etc..
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
- exit_fpu(current);
+ exit_fpu(tsk);
}

void flush_thread(void)
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 2bba7df4ac51..f8e79824e284 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -70,9 +70,10 @@ extern void kernel_thread_starter(void);
/*
* Free current thread data structures etc..
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
- exit_thread_runtime_instr();
+ if (tsk == current)
+ exit_thread_runtime_instr();
}

void flush_thread(void)
diff --git a/arch/sh/kernel/process_64.c b/arch/sh/kernel/process_64.c
index e2062e643341..bfd3855fe120 100644
--- a/arch/sh/kernel/process_64.c
+++ b/arch/sh/kernel/process_64.c
@@ -288,7 +288,7 @@ void show_regs(struct pt_regs *regs)
/*
* Free current thread data structures etc..
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
/*
* See arch/sparc/kernel/process.c for the precedent for doing
@@ -307,7 +307,7 @@ void exit_thread(void)
* which it would get safely nulled.
*/
#ifdef CONFIG_SH_FPU
- if (last_task_used_math == current) {
+ if (last_task_used_math == tsk) {
last_task_used_math = NULL;
}
#endif
diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
index c5113c7ce2fd..b7780a5bef11 100644
--- a/arch/sparc/kernel/process_32.c
+++ b/arch/sparc/kernel/process_32.c
@@ -184,21 +184,21 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
/*
* Free current thread data structures etc..
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
#ifndef CONFIG_SMP
- if(last_task_used_math == current) {
+ if (last_task_used_math == tsk) {
#else
- if (test_thread_flag(TIF_USEDFPU)) {
+ if (test_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU)) {
#endif
/* Keep process from leaving FPU in a bogon state. */
put_psr(get_psr() | PSR_EF);
- fpsave(&current->thread.float_regs[0], &current->thread.fsr,
- &current->thread.fpqueue[0], &current->thread.fpqdepth);
+ fpsave(&tsk->thread.float_regs[0], &tsk->thread.fsr,
+ &tsk->thread.fpqueue[0], &tsk->thread.fpqdepth);
#ifndef CONFIG_SMP
last_task_used_math = NULL;
#else
- clear_thread_flag(TIF_USEDFPU);
+ clear_ti_thread_flag(task_thread_info(tsk), TIF_USEDFPU);
#endif
}
}
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index c16ef1af1843..fa14402b33f9 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -417,9 +417,9 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
}

/* Free current thread data structures etc.. */
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
- struct thread_info *t = current_thread_info();
+ struct thread_info *t = task_thread_info(tsk);

if (t->utraps) {
if (t->utraps[0] < 2)
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index b5f30d376ce1..6b705ccc9cc1 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -541,7 +541,7 @@ void flush_thread(void)
/*
* Free current thread data structures etc..
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
#ifdef CONFIG_HARDWALL
/*
@@ -550,7 +550,7 @@ void exit_thread(void)
* the last reference to a hardwall fd, it would already have
* been released and deactivated at this point.)
*/
- hardwall_deactivate_all(current);
+ hardwall_deactivate_all(tsk);
#endif
}

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 2915d54e9dd5..96becbbb52e0 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -97,10 +97,9 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
/*
* Free current thread data structures etc..
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
- struct task_struct *me = current;
- struct thread_struct *t = &me->thread;
+ struct thread_struct *t = &tsk->thread;
unsigned long *bp = t->io_bitmap_ptr;
struct fpu *fpu = &t->fpu;

diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c
index 5bbfed81c97b..e0ded48561db 100644
--- a/arch/xtensa/kernel/process.c
+++ b/arch/xtensa/kernel/process.c
@@ -115,10 +115,10 @@ void arch_cpu_idle(void)
/*
* This is called when the thread calls exit().
*/
-void exit_thread(void)
+void exit_thread(struct task_struct *tsk)
{
#if XTENSA_HAVE_COPROCESSORS
- coprocessor_release_all(current_thread_info());
+ coprocessor_release_all(task_thread_info(tsk));
#endif
}

diff --git a/include/linux/sched.h b/include/linux/sched.h
index de5370802828..14a2f21ed75a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2648,9 +2648,9 @@ static inline int copy_thread_tls(
extern void flush_thread(void);

#ifdef CONFIG_HAVE_EXIT_THREAD
-extern void exit_thread(void);
+extern void exit_thread(struct task_struct *tsk);
#else
-static inline void exit_thread(void)
+static inline void exit_thread(struct task_struct *tsk)
{
}
#endif
diff --git a/kernel/exit.c b/kernel/exit.c
index fd90195667e1..75b34fe835b2 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -746,7 +746,7 @@ void do_exit(long code)
disassociate_ctty(1);
exit_task_namespaces(tsk);
exit_task_work(tsk);
- exit_thread();
+ exit_thread(tsk);

/*
* Flush inherited counters to the parent - before the parent
--
2.7.4