rcu: Refactor kvfree_call_rcu() and high-level helpers

Currently a kvfree_call_rcu() takes an offset within a structure as
a second parameter, so a helper such as a kvfree_rcu_arg_2() has to
convert rcu_head and a freed ptr to an offset in order to pass it. That
leads to an extra conversion on macro entry.

Instead of converting, refactor the code in way that a pointer that has
to be freed is passed directly to the kvfree_call_rcu().

This patch does not make any functional change and is transparent to
all kvfree_rcu() users.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Uladzislau Rezki (Sony)
2022-10-25 16:46:12 +02:00
committed by Paul E. McKenney
parent 1b929c02af
commit 04a522b7da
5 changed files with 24 additions and 33 deletions

View File

@@ -3103,8 +3103,8 @@ static void kfree_rcu_work(struct work_struct *work)
* This list is named "Channel 3".
*/
for (; head; head = next) {
unsigned long offset = (unsigned long)head->func;
void *ptr = (void *)head - offset;
void *ptr = (void *) head->func;
unsigned long offset = (void *) head - ptr;
next = head->next;
debug_rcu_head_unqueue((struct rcu_head *)ptr);
@@ -3342,26 +3342,21 @@ add_ptr_to_bulk_krc_lock(struct kfree_rcu_cpu **krcp,
* be free'd in workqueue context. This allows us to: batch requests together to
* reduce the number of grace periods during heavy kfree_rcu()/kvfree_rcu() load.
*/
void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
void kvfree_call_rcu(struct rcu_head *head, void *ptr)
{
unsigned long flags;
struct kfree_rcu_cpu *krcp;
bool success;
void *ptr;
if (head) {
ptr = (void *) head - (unsigned long) func;
} else {
/*
* Please note there is a limitation for the head-less
* variant, that is why there is a clear rule for such
* objects: it can be used from might_sleep() context
* only. For other places please embed an rcu_head to
* your data.
*/
/*
* Please note there is a limitation for the head-less
* variant, that is why there is a clear rule for such
* objects: it can be used from might_sleep() context
* only. For other places please embed an rcu_head to
* your data.
*/
if (!head)
might_sleep();
ptr = (unsigned long *) func;
}
// Queue the object but don't yet schedule the batch.
if (debug_rcu_head_queue(ptr)) {
@@ -3382,7 +3377,7 @@ void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
// Inline if kvfree_rcu(one_arg) call.
goto unlock_return;
head->func = func;
head->func = ptr;
head->next = krcp->head;
krcp->head = head;
success = true;