um: Get rid of thread_struct->saved_task

As we have a sane show_stack() now, we can drop
the ->saved_task hack.

Signed-off-by: Richard Weinberger <richard@nod.at>

3 files changed, 4 insertions, 18 deletions

diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 3df3bd544492..29880c9b324e 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -645,11 +645,9 @@ void mconsole_sysrq(struct mc_request *req)
 
 static void stack_proc(void *arg)
 {
-        struct task_struct *from = current, *to = arg;
+        struct task_struct *task = arg;
 
-        to->thread.saved_task = from;
-        rcu_user_hooks_switch(from, to);
-        switch_to(from, to, from);
+        show_stack(task, NULL);
 }
 
 /*
diff --git a/arch/um/include/asm/processor-generic.h b/arch/um/include/asm/processor-generic.h
index 90469031297b..d89b02bb6262 100644
--- a/arch/um/include/asm/processor-generic.h
+++ b/arch/um/include/asm/processor-generic.h
@@ -19,7 +19,6 @@ struct task_struct;
 struct mm_struct;
 
 struct thread_struct {
-        struct task_struct *saved_task;
         struct pt_regs regs;
         struct pt_regs *segv_regs;
         int singlestep_syscall;
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index bbcef522bcb1..eecc4142764c 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -82,19 +82,8 @@ void *__switch_to(struct task_struct *from, struct task_struct *to)
         to->thread.prev_sched = from;
         set_current(to);
 
-        do {
-                current->thread.saved_task = NULL;
-
-                switch_threads(&from->thread.switch_buf,
-                               &to->thread.switch_buf);
-
-                arch_switch_to(current);
-
-                if (current->thread.saved_task)
-                        show_regs(&(current->thread.regs));
-                to = current->thread.saved_task;
-                from = current;
-        } while (current->thread.saved_task);
+        switch_threads(&from->thread.switch_buf, &to->thread.switch_buf);
+        arch_switch_to(current);
 
         return current->thread.prev_sched;
 }