From 3f9120b0424f3e03c75518cb751f9e2bfa73c32a Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 23 Sep 2013 16:27:26 +0200 Subject: [PATCH] driver core: prevent deferred probe with platform_driver_probe Prevent drivers relying on platform_driver_probe from requesting deferred probing in order to avoid further futile probe attempts (either the driver has been unregistered or its probe function has been set to platform_drv_probe_fail when probing is retried). Note that several platform drivers currently return subsystem errors from probe and that these can include -EPROBE_DEFER (e.g. if a gpio request fails). Add a warning to platform_drv_probe that can be used to catch drivers that inadvertently request probe deferral while using platform_driver_probe. Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/base/platform.c | 17 +++++++++++++---- include/linux/platform_device.h | 1 + 2 files changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 4f8bef3eb5a8..47051cd25113 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -488,6 +488,11 @@ static int platform_drv_probe(struct device *_dev) if (ret && ACPI_HANDLE(_dev)) acpi_dev_pm_detach(_dev, true); + if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) { + dev_warn(_dev, "probe deferral not supported\n"); + ret = -ENXIO; + } + return ret; } @@ -553,8 +558,7 @@ EXPORT_SYMBOL_GPL(platform_driver_unregister); /** * platform_driver_probe - register driver for non-hotpluggable device * @drv: platform driver structure - * @probe: the driver probe routine, probably from an __init section, - * must not return -EPROBE_DEFER. + * @probe: the driver probe routine, probably from an __init section * * Use this instead of platform_driver_register() when you know the device * is not hotpluggable and has already been registered, and you want to @@ -565,8 +569,7 @@ EXPORT_SYMBOL_GPL(platform_driver_unregister); * into system-on-chip processors, where the controller devices have been * configured as part of board setup. * - * This is incompatible with deferred probing so probe() must not - * return -EPROBE_DEFER. + * Note that this is incompatible with deferred probing. * * Returns zero if the driver registered and bound to a device, else returns * a negative error code and with the driver not registered. @@ -576,6 +579,12 @@ int __init_or_module platform_driver_probe(struct platform_driver *drv, { int retval, code; + /* + * Prevent driver from requesting probe deferral to avoid further + * futile probe attempts. + */ + drv->prevent_deferred_probe = true; + /* make sure driver won't have bind/unbind attributes */ drv->driver.suppress_bind_attrs = true; diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index ce8e4ffd78c7..16f6654082dd 100644 --- a/include/linux/platform_device.h +++ b/include/linux/platform_device.h @@ -178,6 +178,7 @@ struct platform_driver { int (*resume)(struct platform_device *); struct device_driver driver; const struct platform_device_id *id_table; + bool prevent_deferred_probe; }; #define to_platform_driver(drv) (container_of((drv), struct platform_driver, \ -- 2.20.1