[PATCH v3 27/28] static_call: Use RCU in all users of __module_text_address().

From: Sebastian Andrzej Siewior
Date: Wed Jan 08 2025 - 04:09:45 EST


__module_text_address() can be invoked within a RCU section, there is no
requirement to have preemption disabled.

Replace the preempt_disable() section around __module_text_address()
with RCU.

Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
kernel/static_call_inline.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/kernel/static_call_inline.c b/kernel/static_call_inline.c
index bb7d066a7c397..c2c59e6ef35d0 100644
--- a/kernel/static_call_inline.c
+++ b/kernel/static_call_inline.c
@@ -325,13 +325,12 @@ static int __static_call_mod_text_reserved(void *start, void *end)
struct module *mod;
int ret;

- preempt_disable();
- mod = __module_text_address((unsigned long)start);
- WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
- if (!try_module_get(mod))
- mod = NULL;
- preempt_enable();
-
+ scoped_guard(rcu) {
+ mod = __module_text_address((unsigned long)start);
+ WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
+ if (!try_module_get(mod))
+ mod = NULL;
+ }
if (!mod)
return 0;

--
2.47.1