x86: avoid avoid passing around 'thread_info' in stack dumping code

None of the code actually wants a thread_info, it all wants a
task_struct, and it's just converting to a thread_info pointer much too
early.

No semantic change.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/include/asm/stacktrace.h

@@ -14,7 +14,7 @@ extern int kstack_depth_to_print;
 struct thread_info;
 struct stacktrace_ops;
 
-typedef unsigned long (*walk_stack_t)(struct thread_info *tinfo,
+typedef unsigned long (*walk_stack_t)(struct task_struct *task,
 				      unsigned long *stack,
 				      unsigned long bp,
 				      const struct stacktrace_ops *ops,
@@ -23,13 +23,13 @@ typedef unsigned long (*walk_stack_t)(struct thread_info *tinfo,
 				      int *graph);
 
 extern unsigned long
-print_context_stack(struct thread_info *tinfo,
+print_context_stack(struct task_struct *task,
 		    unsigned long *stack, unsigned long bp,
 		    const struct stacktrace_ops *ops, void *data,
 		    unsigned long *end, int *graph);
 
 extern unsigned long
-print_context_stack_bp(struct thread_info *tinfo,
+print_context_stack_bp(struct task_struct *task,
 		       unsigned long *stack, unsigned long bp,
 		       const struct stacktrace_ops *ops, void *data,
 		       unsigned long *end, int *graph);

arch/x86/kernel/dumpstack.c

@@ -42,16 +42,14 @@ void printk_address(unsigned long address)
 static void
 print_ftrace_graph_addr(unsigned long addr, void *data,
 			const struct stacktrace_ops *ops,
-			struct thread_info *tinfo, int *graph)
+			struct task_struct *task, int *graph)
 {
-	struct task_struct *task;
 	unsigned long ret_addr;
 	int index;
 
 	if (addr != (unsigned long)return_to_handler)
 		return;
 
-	task = tinfo->task;
 	index = task->curr_ret_stack;
 
 	if (!task->ret_stack || index < *graph)
@@ -68,7 +66,7 @@ print_ftrace_graph_addr(unsigned long addr, void *data,
 static inline void
 print_ftrace_graph_addr(unsigned long addr, void *data,
 			const struct stacktrace_ops *ops,
-			struct thread_info *tinfo, int *graph)
+			struct task_struct *task, int *graph)
 { }
 #endif
 
@@ -79,10 +77,10 @@ print_ftrace_graph_addr(unsigned long addr, void *data,
  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  */
 
-static inline int valid_stack_ptr(struct thread_info *tinfo,
+static inline int valid_stack_ptr(struct task_struct *task,
 			void *p, unsigned int size, void *end)
 {
-	void *t = tinfo;
+	void *t = task_thread_info(task);
 	if (end) {
 		if (p < end && p >= (end-THREAD_SIZE))
 			return 1;
@@ -93,14 +91,14 @@ static inline int valid_stack_ptr(struct thread_info *tinfo,
 }
 
 unsigned long
-print_context_stack(struct thread_info *tinfo,
+print_context_stack(struct task_struct *task,
 		unsigned long *stack, unsigned long bp,
 		const struct stacktrace_ops *ops, void *data,
 		unsigned long *end, int *graph)
 {
 	struct stack_frame *frame = (struct stack_frame *)bp;
 
-	while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
+	while (valid_stack_ptr(task, stack, sizeof(*stack), end)) {
 		unsigned long addr;
 
 		addr = *stack;
@@ -112,7 +110,7 @@ print_context_stack(struct thread_info *tinfo,
 			} else {
 				ops->address(data, addr, 0);
 			}
-			print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
+			print_ftrace_graph_addr(addr, data, ops, task, graph);
 		}
 		stack++;
 	}
@@ -121,7 +119,7 @@ print_context_stack(struct thread_info *tinfo,
 EXPORT_SYMBOL_GPL(print_context_stack);
 
 unsigned long
-print_context_stack_bp(struct thread_info *tinfo,
+print_context_stack_bp(struct task_struct *task,
 		       unsigned long *stack, unsigned long bp,
 		       const struct stacktrace_ops *ops, void *data,
 		       unsigned long *end, int *graph)
@@ -129,7 +127,7 @@ print_context_stack_bp(struct thread_info *tinfo,
 	struct stack_frame *frame = (struct stack_frame *)bp;
 	unsigned long *ret_addr = &frame->return_address;
 
-	while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
+	while (valid_stack_ptr(task, ret_addr, sizeof(*ret_addr), end)) {
 		unsigned long addr = *ret_addr;
 
 		if (!__kernel_text_address(addr))
@@ -139,7 +137,7 @@ print_context_stack_bp(struct thread_info *tinfo,
 			break;
 		frame = frame->next_frame;
 		ret_addr = &frame->return_address;
-		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
+		print_ftrace_graph_addr(addr, data, ops, task, graph);
 	}
 
 	return (unsigned long)frame;

arch/x86/kernel/dumpstack_32.c

@@ -61,15 +61,13 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 		bp = stack_frame(task, regs);
 
 	for (;;) {
-		struct thread_info *context;
 		void *end_stack;
 
 		end_stack = is_hardirq_stack(stack, cpu);
 		if (!end_stack)
 			end_stack = is_softirq_stack(stack, cpu);
 
-		context = task_thread_info(task);
-		bp = ops->walk_stack(context, stack, bp, ops, data,
+		bp = ops->walk_stack(task, stack, bp, ops, data,
 				     end_stack, &graph);
 
 		/* Stop if not on irq stack */

arch/x86/kernel/dumpstack_64.c

@@ -153,7 +153,6 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 		const struct stacktrace_ops *ops, void *data)
 {
 	const unsigned cpu = get_cpu();
-	struct thread_info *tinfo;
 	unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
 	unsigned long dummy;
 	unsigned used = 0;
@@ -179,7 +178,6 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 	 * current stack address. If the stacks consist of nested
 	 * exceptions
 	 */
-	tinfo = task_thread_info(task);
 	while (!done) {
 		unsigned long *stack_end;
 		enum stack_type stype;
@@ -202,7 +200,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 			if (ops->stack(data, id) < 0)
 				break;
 
-			bp = ops->walk_stack(tinfo, stack, bp, ops,
+			bp = ops->walk_stack(task, stack, bp, ops,
 					     data, stack_end, &graph);
 			ops->stack(data, "<EOE>");
 			/*
@@ -218,7 +216,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 
 			if (ops->stack(data, "IRQ") < 0)
 				break;
-			bp = ops->walk_stack(tinfo, stack, bp,
+			bp = ops->walk_stack(task, stack, bp,
 				     ops, data, stack_end, &graph);
 			/*
 			 * We link to the next stack (which would be
@@ -240,7 +238,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 	/*
 	 * This handles the process stack:
 	 */
-	bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
+	bp = ops->walk_stack(task, stack, bp, ops, data, NULL, &graph);
 	put_cpu();
 }
 EXPORT_SYMBOL(dump_trace);