cpu/hotplug: Fix dynstate assignment in __cpuhp_setup_state_cpuslocked()

Commit 4205e4786d0b ("cpu/hotplug: Provide dynamic range for prepare
stage") added a dynamic range for the prepare states, but did not handle
the assignment of the dynstate variable in __cpuhp_setup_state_cpuslocked().

This causes the corresponding startup callback not to be invoked when
calling __cpuhp_setup_state_cpuslocked() with the CPUHP_BP_PREPARE_DYN
parameter, even though it should be.

Currently, the users of __cpuhp_setup_state_cpuslocked(), for one reason or
another, have not triggered this bug.

Fixes: 4205e4786d0b ("cpu/hotplug: Provide dynamic range for prepare stage")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240515134554.427071-1-ytcoode@gmail.com

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 563877d6c28b65f40a9e5597c865e0afa1200a64..74cfdb66a9bdd259d0a9659e9c041681f1cba8d7 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2446,7 +2446,7 @@ EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
  * The caller needs to hold cpus read locked while calling this function.
  * Return:
  *   On success:
- *      Positive state number if @state is CPUHP_AP_ONLINE_DYN;
+ *      Positive state number if @state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN;
  *      0 for all other states
  *   On failure: proper (negative) error code
  */
@@ -2469,7 +2469,7 @@ int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state,
        ret = cpuhp_store_callbacks(state, name, startup, teardown,
                                    multi_instance);
 
-       dynstate = state == CPUHP_AP_ONLINE_DYN;
+       dynstate = state == CPUHP_AP_ONLINE_DYN || state == CPUHP_BP_PREPARE_DYN;
        if (ret > 0 && dynstate) {
                state = ret;
                ret = 0;
@@ -2500,8 +2500,8 @@ int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state,
 out:
        mutex_unlock(&cpuhp_state_mutex);
        /*
-        * If the requested state is CPUHP_AP_ONLINE_DYN, return the
-        * dynamically allocated state in case of success.
+        * If the requested state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN,
+        * return the dynamically allocated state in case of success.
         */
        if (!ret && dynstate)
                return state;