Mailing List Archive

In the case that a delay is acceptable for 'crng_set_ready', it can be
deferred to a workqueue in order to accommodate different contexts.

Signed-off-by: Guoyong Wang <guoyong.wang@mediatek.com>
---
v2: Compared to version 1, version 2 has removed the definition of
'execute_in_non_atomic_context' and always uses a workqueue to execute
'crng_set_ready'.

Send out the patch again for further discussion.

[1]: https://patchwork.kernel.org/patch/13595066

---
drivers/char/random.c | 10 +++++-----
include/linux/workqueue.h | 1 -
kernel/workqueue.c | 26 --------------------------
3 files changed, 5 insertions(+), 32 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 00be9426a6fc..2597cb43f438 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -702,7 +702,7 @@ static void extract_entropy(void *buf, size_t len)

static void __cold _credit_init_bits(size_t bits)
{
- static struct execute_work set_ready;
+ static DECLARE_WORK(set_ready, crng_set_ready);
unsigned int new, orig, add;
unsigned long flags;

@@ -718,8 +718,8 @@ static void __cold _credit_init_bits(size_t bits)

if (orig < POOL_READY_BITS && new >= POOL_READY_BITS) {
crng_reseed(NULL); /* Sets crng_init to CRNG_READY under base_crng.lock. */
- if (static_key_initialized)
- execute_in_non_atomic_context(crng_set_ready, &set_ready);
+ if (static_key_initialized && system_unbound_wq)
+ queue_work(system_unbound_wq, &set_ready);
atomic_notifier_call_chain(&random_ready_notifier, 0, NULL);
wake_up_interruptible(&crng_init_wait);
kill_fasync(&fasync, SIGIO, POLL_IN);
@@ -890,8 +890,8 @@ void __init random_init(void)

/*
* If we were initialized by the cpu or bootloader before jump labels
- * are initialized, then we should enable the static branch here, where
- * it's guaranteed that jump labels have been initialized.
+ * or workqueues are initialized, then we should enable the static
+ * branch here, where it's guaranteed that these have been initialized.
*/
if (!static_branch_likely(&crng_is_ready) && crng_init >= CRNG_READY)
crng_set_ready(NULL);
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index eb17c62d23aa..158784dd189a 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -550,7 +550,6 @@ extern void drain_workqueue(struct workqueue_struct *wq);
extern int schedule_on_each_cpu(work_func_t func);

int execute_in_process_context(work_func_t fn, struct execute_work *);
-int execute_in_non_atomic_context(work_func_t fn, struct execute_work *ew);

extern bool flush_work(struct work_struct *work);
extern bool cancel_work(struct work_struct *work);
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 8f212346da7a..bf2bdac46843 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4449,32 +4449,6 @@ int execute_in_process_context(work_func_t fn, struct execute_work *ew)
}
EXPORT_SYMBOL_GPL(execute_in_process_context);

-/**
- * execute_in_non_atomic_context - reliably execute the routine with user context
- * @fn: the function to execute
- * @ew: guaranteed storage for the execute work structure (must
- * be available when the work executes)
- *
- * Schedules the function for delayed execution if atomic context is available,
- * otherwise executes the function immediately .
- *
- * Return: 0 - function was executed
- * 1 - function was scheduled for execution
- */
-int execute_in_non_atomic_context(work_func_t fn, struct execute_work *ew)
-{
- if (!in_atomic()) {
- fn(&ew->work);
- return 0;
- }
-
- INIT_WORK(&ew->work, fn);
- schedule_work(&ew->work);
-
- return 1;
-}
-EXPORT_SYMBOL_GPL(execute_in_non_atomic_context);
-
/**
* free_workqueue_attrs - free a workqueue_attrs
* @attrs: workqueue_attrs to free
--
2.18.0