[PATCH 8/8] kernel/fork: Use IS_ENABLED() in account_kernel_stack().

From: Sebastian Andrzej Siewior
Date: Thu Nov 18 2021 - 09:35:41 EST


Not strickly needed but checking CONFIG_VMAP_STACK instead of
task_stack_vm_area()' result allows the compiler the remove the else
path in the CONFIG_VMAP_STACK case where the pointer can't be NULL.

Check for CONFIG_VMAP_STACK in order to use the proper path.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
kernel/fork.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 0aa079e56e3b4..15286e469cf2e 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -465,16 +465,16 @@ void vm_area_free(struct vm_area_struct *vma)

static void account_kernel_stack(struct task_struct *tsk, int account)
{
- void *stack = task_stack_page(tsk);
- struct vm_struct *vm = task_stack_vm_area(tsk);
-
- if (vm) {
+ if (IS_ENABLED(CONFIG_VMAP_STACK)) {
+ struct vm_struct *vm = task_stack_vm_area(tsk);
int i;

for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB,
account * (PAGE_SIZE / 1024));
} else {
+ void *stack = task_stack_page(tsk);
+
/* All stack pages are in the same node. */
mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB,
account * (THREAD_SIZE / 1024));
--
2.33.1