[PATCH] drivers: base: Set mod->async_probe_requested if needed

[PATCH] drivers: base: Set mod->async_probe_requested if needed

[Bart Van Assche]

If PROBE_PREFER_ASYNCHRONOUS is set for a device driver, and if loading
other kernel modules depends on probing of that device driver to
complete, e.g. because it is a storage driver, and if
mod->async_probe_requested has not been set, then the
async_synchronize_full() call in do_init_module() introduces a delay.
Fix this by setting mod->async_probe_requested if
PROBE_PREFER_ASYNCHRONOUS has been set. This patch reduces the Pixel 10
boot time by 100 ms.

Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Daniel Gomez <da.gomez@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Igor Pylypiv <ipylypiv@google.com>
Cc: Chung-Kai Mei <chungkai@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/base/module.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/base/module.c b/drivers/base/module.c
index 218aaa096455..e58fc189d389 100644
--- a/drivers/base/module.c
+++ b/drivers/base/module.c
@@ -39,6 +39,9 @@ int module_add_driver(struct module *mod, const struct device_driver *drv)
 	if (!drv)
 		return 0;
 
+	if (mod && drv->probe_type == PROBE_PREFER_ASYNCHRONOUS)
+		mod->async_probe_requested = true;
+
 	if (mod)
 		mk = &mod->mkobj;
 	else if (drv->mod_name) {