From 2451e746478a6a6e981cfa66b62b791ca93b90c8 Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Wed, 1 Jul 2020 12:42:59 -0700 Subject: [PATCH] driver core: Avoid deferred probe due to fw_devlink_pause/resume() With the earlier patch in this series, all devices that deferred probe due to fw_devlink_pause() will have their probes delayed till the deferred probe thread is kicked off during late_initcall. This will also affect all their consumers. This delayed probing in unnecessary. So this patch just keeps track of the devices that had their probe deferred due to fw_devlink_pause() and attempts to probe them once during fw_devlink_resume(). 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/20200701194259.3337652-4-saravanak@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 21 +++++++++++++++++++++ include/linux/device.h | 3 ++- 2 files changed, 23 insertions(+), 1 deletion(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index d1d2cdc..05d414e 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -50,6 +50,7 @@ static DEFINE_MUTEX(wfs_lock); static LIST_HEAD(deferred_sync); static unsigned int defer_sync_state_count = 1; static unsigned int defer_fw_devlink_count; +static LIST_HEAD(deferred_fw_devlink); static DEFINE_MUTEX(defer_fw_devlink_lock); static bool fw_devlink_is_permissive(void); @@ -1244,6 +1245,12 @@ static void fw_devlink_link_device(struct device *dev) fw_ret = -EAGAIN; } else { fw_ret = -ENODEV; + /* + * defer_hook is not used to add device to deferred_sync list + * until device is bound. Since deferred fw devlink also blocks + * probing, same list hook can be used for deferred_fw_devlink. + */ + list_add_tail(&dev->links.defer_hook, &deferred_fw_devlink); } if (fw_ret == -ENODEV) @@ -1312,6 +1319,9 @@ void fw_devlink_pause(void) */ void fw_devlink_resume(void) { + struct device *dev, *tmp; + LIST_HEAD(probe_list); + mutex_lock(&defer_fw_devlink_lock); if (!defer_fw_devlink_count) { WARN(true, "Unmatched fw_devlink pause/resume!"); @@ -1323,8 +1333,19 @@ void fw_devlink_resume(void) goto out; device_link_add_missing_supplier_links(); + list_splice_tail_init(&deferred_fw_devlink, &probe_list); out: mutex_unlock(&defer_fw_devlink_lock); + + /* + * bus_probe_device() can cause new devices to get added and they'll + * try to grab defer_fw_devlink_lock. So, this needs to be done outside + * the defer_fw_devlink_lock. + */ + list_for_each_entry_safe(dev, tmp, &probe_list, links.defer_hook) { + list_del_init(&dev->links.defer_hook); + bus_probe_device(dev); + } } /* Device links support end. */ diff --git a/include/linux/device.h b/include/linux/device.h index 9bb2bc7..5efed86 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -433,7 +433,8 @@ enum dl_dev_state { * @suppliers: List of links to supplier devices. * @consumers: List of links to consumer devices. * @needs_suppliers: Hook to global list of devices waiting for suppliers. - * @defer_hook: Hook to global list of devices that have deferred sync_state. + * @defer_hook: Hook to global list of devices that have deferred sync_state or + * deferred fw_devlink. * @need_for_probe: If needs_suppliers is on a list, this indicates if the * suppliers are needed for probe or not. * @status: Driver status information. -- 2.7.4