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authorLinus Torvalds <torvalds@linux-foundation.org>2016-06-24 15:09:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-06-24 15:09:37 -0700
commitb235beea9e996a4d36fed6cfef4801a3e7d7a9a5 (patch)
tree52f66350a5e07e251bb241c53520dc485b5d750a /arch
parent63c04ee7d3b7c8d8e2726cb7c5f8a5f6fcc1e3b2 (diff)
Clarify naming of thread info/stack allocators
We've had the thread info allocated together with the thread stack for most architectures for a long time (since the thread_info was split off from the task struct), but that is about to change. But the patches that move the thread info to be off-stack (and a part of the task struct instead) made it clear how confused the allocator and freeing functions are. Because the common case was that we share an allocation with the thread stack and the thread_info, the two pointers were identical. That identity then meant that we would have things like ti = alloc_thread_info_node(tsk, node); ... tsk->stack = ti; which certainly _worked_ (since stack and thread_info have the same value), but is rather confusing: why are we assigning a thread_info to the stack? And if we move the thread_info away, the "confusing" code just gets to be entirely bogus. So remove all this confusion, and make it clear that we are doing the stack allocation by renaming and clarifying the function names to be about the stack. The fact that the thread_info then shares the allocation is an implementation detail, and not really about the allocation itself. This is a pure renaming and type fix: we pass in the same pointer, it's just that we clarify what the pointer means. The ia64 code that actually only has one single allocation (for all of task_struct, thread_info and kernel thread stack) now looks a bit odd, but since "tsk->stack" is actually not even used there, that oddity doesn't matter. It would be a separate thing to clean that up, I intentionally left the ia64 changes as a pure brute-force renaming and type change. Acked-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/Kconfig4
-rw-r--r--arch/ia64/Kconfig2
-rw-r--r--arch/ia64/include/asm/thread_info.h8
-rw-r--r--arch/mn10300/include/asm/thread_info.h2
-rw-r--r--arch/mn10300/kernel/kgdb.c3
-rw-r--r--arch/tile/include/asm/thread_info.h2
-rw-r--r--arch/tile/kernel/process.c3
7 files changed, 13 insertions, 11 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index e9734796531f..15996290fed4 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -226,8 +226,8 @@ config ARCH_INIT_TASK
config ARCH_TASK_STRUCT_ALLOCATOR
bool
-# Select if arch has its private alloc_thread_info() function
-config ARCH_THREAD_INFO_ALLOCATOR
+# Select if arch has its private alloc_thread_stack() function
+config ARCH_THREAD_STACK_ALLOCATOR
bool
# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index f80758cb7157..e109ee95e919 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -45,7 +45,7 @@ config IA64
select GENERIC_SMP_IDLE_THREAD
select ARCH_INIT_TASK
select ARCH_TASK_STRUCT_ALLOCATOR
- select ARCH_THREAD_INFO_ALLOCATOR
+ select ARCH_THREAD_STACK_ALLOCATOR
select ARCH_CLOCKSOURCE_DATA
select GENERIC_TIME_VSYSCALL_OLD
select SYSCTL_ARCH_UNALIGN_NO_WARN
diff --git a/arch/ia64/include/asm/thread_info.h b/arch/ia64/include/asm/thread_info.h
index aa995b67c3f5..d1212b84fb83 100644
--- a/arch/ia64/include/asm/thread_info.h
+++ b/arch/ia64/include/asm/thread_info.h
@@ -48,15 +48,15 @@ struct thread_info {
#ifndef ASM_OFFSETS_C
/* how to get the thread information struct from C */
#define current_thread_info() ((struct thread_info *) ((char *) current + IA64_TASK_SIZE))
-#define alloc_thread_info_node(tsk, node) \
- ((struct thread_info *) ((char *) (tsk) + IA64_TASK_SIZE))
+#define alloc_thread_stack_node(tsk, node) \
+ ((unsigned long *) ((char *) (tsk) + IA64_TASK_SIZE))
#define task_thread_info(tsk) ((struct thread_info *) ((char *) (tsk) + IA64_TASK_SIZE))
#else
#define current_thread_info() ((struct thread_info *) 0)
-#define alloc_thread_info_node(tsk, node) ((struct thread_info *) 0)
+#define alloc_thread_stack_node(tsk, node) ((unsigned long *) 0)
#define task_thread_info(tsk) ((struct thread_info *) 0)
#endif
-#define free_thread_info(ti) /* nothing */
+#define free_thread_stack(ti) /* nothing */
#define task_stack_page(tsk) ((void *)(tsk))
#define __HAVE_THREAD_FUNCTIONS
diff --git a/arch/mn10300/include/asm/thread_info.h b/arch/mn10300/include/asm/thread_info.h
index 4861a78c7160..f5f90bbf019d 100644
--- a/arch/mn10300/include/asm/thread_info.h
+++ b/arch/mn10300/include/asm/thread_info.h
@@ -115,7 +115,7 @@ static inline unsigned long current_stack_pointer(void)
}
#ifndef CONFIG_KGDB
-void arch_release_thread_info(struct thread_info *ti);
+void arch_release_thread_stack(unsigned long *stack);
#endif
#define get_thread_info(ti) get_task_struct((ti)->task)
#define put_thread_info(ti) put_task_struct((ti)->task)
diff --git a/arch/mn10300/kernel/kgdb.c b/arch/mn10300/kernel/kgdb.c
index 99770823451a..2d7986c386fe 100644
--- a/arch/mn10300/kernel/kgdb.c
+++ b/arch/mn10300/kernel/kgdb.c
@@ -397,8 +397,9 @@ static bool kgdb_arch_undo_singlestep(struct pt_regs *regs)
* single-step state is cleared. At this point the breakpoints should have
* been removed by __switch_to().
*/
-void arch_release_thread_info(struct thread_info *ti)
+void arch_release_thread_stack(unsigned long *stack)
{
+ struct thread_info *ti = (void *)stack;
if (kgdb_sstep_thread == ti) {
kgdb_sstep_thread = NULL;
diff --git a/arch/tile/include/asm/thread_info.h b/arch/tile/include/asm/thread_info.h
index 4b7cef9e94e0..c1467ac59ce6 100644
--- a/arch/tile/include/asm/thread_info.h
+++ b/arch/tile/include/asm/thread_info.h
@@ -78,7 +78,7 @@ struct thread_info {
#ifndef __ASSEMBLY__
-void arch_release_thread_info(struct thread_info *info);
+void arch_release_thread_stack(unsigned long *stack);
/* How to get the thread information struct from C. */
register unsigned long stack_pointer __asm__("sp");
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index 6b705ccc9cc1..a465d8372edd 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -73,8 +73,9 @@ void arch_cpu_idle(void)
/*
* Release a thread_info structure
*/
-void arch_release_thread_info(struct thread_info *info)
+void arch_release_thread_stack(unsigned long *stack)
{
+ struct thread_info *info = (void *)stack;
struct single_step_state *step_state = info->step_state;
if (step_state) {