From 2b2b5b944c36f9ba96a110d6db76ce68ee5b94f4 Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Wed, 1 Jul 2020 12:42:57 -0700 Subject: [PATCH] UPSTREAM: driver core: Don't do deferred probe in parallel with kernel_init thread The current deferred probe implementation can mess up suspend/resume ordering if deferred probe thread is kicked off in parallel with the main initcall thread (kernel_init thread) [1]. For example: Say device-B is a consumer of device-A. Initcall thread Deferred probe thread =============== ===================== 1. device-A is added. 2. device-B is added. 3. dpm_list is now [device-A, device-B]. 4. driver-A defers probe of device-A. 5. device-A is moved to end of dpm_list 6. dpm_list is now [device-B, device-A] 7. driver-B is registereed and probes device-B. 8. dpm_list stays as [device-B, device-A]. The reverse order of dpm_list is used for suspend. So in this case device-A would incorrectly get suspended before device-B. Commit 716a7a259690 ("driver core: fw_devlink: Add support for batching fwnode parsing") kicked off the deferred probe thread early during boot to run in parallel with the initcall thread and caused suspend/resume regressions. This patch removes the parallel run of the deferred probe thread to avoid the suspend/resume regressions. [1] - https://lore.kernel.org/lkml/CAGETcx8W96KAw-d_siTX4qHB_-7ddk0miYRDQeHE6E0_8qx-6Q@mail.gmail.com/ Fixes: 716a7a259690 ("driver core: fw_devlink: Add support for batching fwnode parsing") Signed-off-by: Saravana Kannan Tested-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20200701194259.3337652-2-saravanak@google.com Signed-off-by: Greg Kroah-Hartman (cherry picked from commit cec72f3efc6272420c2c2c699607f03d09b93e41) Signed-off-by: Saravana Kannan Bug: 157691602 Change-Id: I13f61a7cbeb705eb6ca1c67b07df5a9b69045029 --- drivers/base/base.h | 1 - drivers/base/core.c | 1 - drivers/base/dd.c | 5 ----- 3 files changed, 7 deletions(-) diff --git a/drivers/base/base.h b/drivers/base/base.h index 2faf767d18dc..0d32544b6f91 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -142,7 +142,6 @@ extern char *make_class_name(const char *name, struct kobject *kobj); extern int devres_release_all(struct device *dev); extern void device_block_probing(void); extern void device_unblock_probing(void); -extern void driver_deferred_probe_force_trigger(void); /* /sys/devices directory */ extern struct kset *devices_kset; diff --git a/drivers/base/core.c b/drivers/base/core.c index 6764f1827523..a32b1c32611c 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1287,7 +1287,6 @@ void fw_devlink_resume(void) goto out; device_link_add_missing_supplier_links(); - driver_deferred_probe_force_trigger(); out: mutex_unlock(&defer_fw_devlink_lock); } diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 802f03eb3c37..b25bcab2a26b 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -164,11 +164,6 @@ static void driver_deferred_probe_trigger(void) if (!driver_deferred_probe_enable) return; - driver_deferred_probe_force_trigger(); -} - -void driver_deferred_probe_force_trigger(void) -{ /* * A successful probe means that all the devices in the pending list * should be triggered to be reprobed. Move all the deferred devices