ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations

It is proven that Windows evaluates _Qxx handlers in a parallel way. This
patch follows this fact, splits _Qxx evaluations from the NOTIFY queue to
form a separate queue, so that _Qxx evaluations can be queued up on
different CPUs rather than being queued up on a CPU0 bound queue.
Event handling related callbacks are also renamed and sorted in this patch.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=94411
Reported-and-tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 9d4761d2f6b77b82f10dda7027c707d4e241895c..3e57ee7c890f3eb3e7dfbd094f3b0ce08cbd81e3 100644 (file)
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -165,8 +165,16 @@ struct transaction {
        u8 flags;
 };
 
+struct acpi_ec_query {
+       struct transaction transaction;
+       struct work_struct work;
+       struct acpi_ec_query_handler *handler;
+};
+
 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
 static void advance_transaction(struct acpi_ec *ec);
+static void acpi_ec_event_handler(struct work_struct *work);
+static void acpi_ec_event_processor(struct work_struct *work);
 
 struct acpi_ec *boot_ec, *first_ec;
 EXPORT_SYMBOL(first_ec);
@@ -978,60 +986,90 @@ void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
 }
 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
 
-static void acpi_ec_run(void *cxt)
+static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
 {
-       struct acpi_ec_query_handler *handler = cxt;
+       struct acpi_ec_query *q;
+       struct transaction *t;
+
+       q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
+       if (!q)
+               return NULL;
+       INIT_WORK(&q->work, acpi_ec_event_processor);
+       t = &q->transaction;
+       t->command = ACPI_EC_COMMAND_QUERY;
+       t->rdata = pval;
+       t->rlen = 1;
+       return q;
+}
+
+static void acpi_ec_delete_query(struct acpi_ec_query *q)
+{
+       if (q) {
+               if (q->handler)
+                       acpi_ec_put_query_handler(q->handler);
+               kfree(q);
+       }
+}
+
+static void acpi_ec_event_processor(struct work_struct *work)
+{
+       struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
+       struct acpi_ec_query_handler *handler = q->handler;
 
-       if (!handler)
-               return;
        ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
        if (handler->func)
                handler->func(handler->data);
        else if (handler->handle)
                acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
        ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
-       acpi_ec_put_query_handler(handler);
+       acpi_ec_delete_query(q);
 }
 
 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
 {
        u8 value = 0;
        int result;
-       acpi_status status;
        struct acpi_ec_query_handler *handler;
-       struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
-                               .wdata = NULL, .rdata = &value,
-                               .wlen = 0, .rlen = 1};
+       struct acpi_ec_query *q;
+
+       q = acpi_ec_create_query(&value);
+       if (!q)
+               return -ENOMEM;
 
        /*
         * Query the EC to find out which _Qxx method we need to evaluate.
         * Note that successful completion of the query causes the ACPI_EC_SCI
         * bit to be cleared (and thus clearing the interrupt source).
         */
-       result = acpi_ec_transaction(ec, &t);
-       if (result)
-               return result;
-       if (data)
-               *data = value;
+       result = acpi_ec_transaction(ec, &q->transaction);
        if (!value)
-               return -ENODATA;
+               result = -ENODATA;
+       if (result)
+               goto err_exit;
 
        mutex_lock(&ec->mutex);
        list_for_each_entry(handler, &ec->list, node) {
                if (value == handler->query_bit) {
-                       /* have custom handler for this bit */
-                       handler = acpi_ec_get_query_handler(handler);
+                       q->handler = acpi_ec_get_query_handler(handler);
                        ec_dbg_evt("Query(0x%02x) scheduled",
-                                  handler->query_bit);
-                       status = acpi_os_execute((handler->func) ?
-                               OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
-                               acpi_ec_run, handler);
-                       if (ACPI_FAILURE(status))
+                                  q->handler->query_bit);
+                       /*
+                        * It is reported that _Qxx are evaluated in a
+                        * parallel way on Windows:
+                        * https://bugzilla.kernel.org/show_bug.cgi?id=94411
+                        */
+                       if (!schedule_work(&q->work))
                                result = -EBUSY;
                        break;
                }
        }
        mutex_unlock(&ec->mutex);
+
+err_exit:
+       if (result && q)
+               acpi_ec_delete_query(q);
+       if (data)
+               *data = value;
        return result;
 }