Hi Dan, First of all, sorry for late reply. There is one issue. About this issue, I already discussed on patch[1] [1] https://lore.kernel.org/lkml/5BEB63C3.1020504@xxxxxxxxxxx/ extcon_get_extcon_dev() is used for anywhere except for probe step. But EPROBE_DEFER is only used on probe step. So that it is not clear to return EPROBE_DEFER from extcon_get_extcon_dev() because extcon_get_extcon_dev() never know either call it on probe function or not. On 11/23/21 5:43 PM, Dan Carpenter wrote: > The extcon_get_extcon_dev() function returns error pointers on error, > NULL when it's a -EPROBE_DEFER defer situation, and ERR_PTR(-ENODEV) > when the CONFIG_EXTCON option is disabled. This is very complicated for > the callers to handle and a number of them had bugs that would lead to > an Oops. > > In real life, there are two things which prevented crashes. First, > error pointers would only be returned if there was bug in the caller > where they passed a NULL "extcon_name" and none of them do that. > Second, only two out of the eight drivers will build when CONFIG_EXTCON > is disabled. > > The normal way to write this would be to return -EPROBE_DEFER directly > when appropriate and return NULL when CONFIG_EXTCON is disabled. Then > the error handling is simple and just looks like: > > dev->edev = extcon_get_extcon_dev(acpi_dev_name(adev)); > if (IS_ERR(dev->edev)) > return PTR_ERR(dev->edev); > > For the two drivers which can build with CONFIG_EXTCON disabled, then > extcon_get_extcon_dev() will now return NULL which is not treated as an > error and the probe will continue successfully. Those two drivers are > "typec_fusb302" and "max8997-battery". In the original code, the > typec_fusb302 driver had an 800ms hang in tcpm_get_current_limit() but > now that function is a no-op. For the max8997-battery driver everything > should continue working as is. > > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > --- > v2: return NULL when CONFIG_EXTCON is disabled > > If we apply this patch, it might be a good idea to send it to -stable > so that backported code that relies on handling error pointers does > not break silently. > > drivers/extcon/extcon-axp288.c | 4 ++-- > drivers/extcon/extcon.c | 2 +- > drivers/power/supply/axp288_charger.c | 17 ++++++++++------- > drivers/power/supply/charger-manager.c | 7 ++----- > drivers/power/supply/max8997_charger.c | 10 +++++----- > drivers/usb/dwc3/drd.c | 9 ++------- > drivers/usb/phy/phy-omap-otg.c | 4 ++-- > drivers/usb/typec/tcpm/fusb302.c | 4 ++-- > include/linux/extcon.h | 2 +- > 9 files changed, 27 insertions(+), 32 deletions(-) > > diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c > index e7a9561a826d..a35e99928807 100644 > --- a/drivers/extcon/extcon.c > +++ b/drivers/extcon/extcon.c > @@ -876,7 +876,7 @@ struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name) > if (!strcmp(sd->name, extcon_name)) > goto out; > } > - sd = NULL; > + sd = ERR_PTR(-EPROBE_DEFER); > out: > mutex_unlock(&extcon_dev_list_lock); > return sd; > diff --git a/include/linux/extcon.h b/include/linux/extcon.h > index 0c19010da77f..685401d94d39 100644 > --- a/include/linux/extcon.h > +++ b/include/linux/extcon.h > @@ -296,7 +296,7 @@ static inline void devm_extcon_unregister_notifier_all(struct device *dev, > > static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name) > { > - return ERR_PTR(-ENODEV); > + return NULL; > } > > static inline struct extcon_dev *extcon_find_edev_by_node(struct device_node *node) > diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c > index 7c6d5857ff25..180be768c215 100644 > --- a/drivers/extcon/extcon-axp288.c > +++ b/drivers/extcon/extcon-axp288.c > @@ -394,8 +394,8 @@ static int axp288_extcon_probe(struct platform_device *pdev) > if (adev) { > info->id_extcon = extcon_get_extcon_dev(acpi_dev_name(adev)); > put_device(&adev->dev); > - if (!info->id_extcon) > - return -EPROBE_DEFER; > + if (IS_ERR(info->id_extcon)) > + return PTR_ERR(info->id_extcon); > > dev_info(dev, "controlling USB role\n"); > } else { > diff --git a/drivers/power/supply/axp288_charger.c b/drivers/power/supply/axp288_charger.c > index ec41f6cd3f93..4acfeb52a44e 100644 > --- a/drivers/power/supply/axp288_charger.c > +++ b/drivers/power/supply/axp288_charger.c > @@ -848,17 +848,20 @@ static int axp288_charger_probe(struct platform_device *pdev) > info->regmap_irqc = axp20x->regmap_irqc; > > info->cable.edev = extcon_get_extcon_dev(AXP288_EXTCON_DEV_NAME); > - if (info->cable.edev == NULL) { > - dev_dbg(dev, "%s is not ready, probe deferred\n", > - AXP288_EXTCON_DEV_NAME); > - return -EPROBE_DEFER; > + if (IS_ERR(info->cable.edev)) { > + dev_err_probe(dev, PTR_ERR(info->cable.edev), > + "extcon_get_extcon_dev(%s) failed\n", > + AXP288_EXTCON_DEV_NAME); > + return PTR_ERR(info->cable.edev); > } > > if (acpi_dev_present(USB_HOST_EXTCON_HID, NULL, -1)) { > info->otg.cable = extcon_get_extcon_dev(USB_HOST_EXTCON_NAME); > - if (info->otg.cable == NULL) { > - dev_dbg(dev, "EXTCON_USB_HOST is not ready, probe deferred\n"); > - return -EPROBE_DEFER; > + if (IS_ERR(info->otg.cable)) { > + dev_err_probe(dev, PTR_ERR(info->otg.cable), > + "extcon_get_extcon_dev(%s) failed\n", > + USB_HOST_EXTCON_NAME); > + return PTR_ERR(info->otg.cable); > } > dev_info(dev, "Using " USB_HOST_EXTCON_HID " extcon for usb-id\n"); > } > diff --git a/drivers/power/supply/charger-manager.c b/drivers/power/supply/charger-manager.c > index d67edb760c94..92db79400a6a 100644 > --- a/drivers/power/supply/charger-manager.c > +++ b/drivers/power/supply/charger-manager.c > @@ -985,13 +985,10 @@ static int charger_extcon_init(struct charger_manager *cm, > cable->nb.notifier_call = charger_extcon_notifier; > > cable->extcon_dev = extcon_get_extcon_dev(cable->extcon_name); > - if (IS_ERR_OR_NULL(cable->extcon_dev)) { > + if (IS_ERR(cable->extcon_dev)) { > pr_err("Cannot find extcon_dev for %s (cable: %s)\n", > cable->extcon_name, cable->name); > - if (cable->extcon_dev == NULL) > - return -EPROBE_DEFER; > - else > - return PTR_ERR(cable->extcon_dev); > + return PTR_ERR(cable->extcon_dev); > } > > for (i = 0; i < ARRAY_SIZE(extcon_mapping); i++) { > diff --git a/drivers/power/supply/max8997_charger.c b/drivers/power/supply/max8997_charger.c > index 25207fe2aa68..634658adf313 100644 > --- a/drivers/power/supply/max8997_charger.c > +++ b/drivers/power/supply/max8997_charger.c > @@ -248,13 +248,13 @@ static int max8997_battery_probe(struct platform_device *pdev) > dev_info(&pdev->dev, "couldn't get charger regulator\n"); > } > charger->edev = extcon_get_extcon_dev("max8997-muic"); > - if (IS_ERR_OR_NULL(charger->edev)) { > - if (!charger->edev) > - return -EPROBE_DEFER; > - dev_info(charger->dev, "couldn't get extcon device\n"); > + if (IS_ERR(charger->edev)) { > + dev_err_probe(charger->dev, PTR_ERR(charger->edev), > + "couldn't get extcon device: max8997-muic\n"); > + return PTR_ERR(charger->edev); > } > > - if (!IS_ERR(charger->reg) && !IS_ERR_OR_NULL(charger->edev)) { > + if (!IS_ERR(charger->reg)) { > INIT_WORK(&charger->extcon_work, max8997_battery_extcon_evt_worker); > ret = devm_add_action(&pdev->dev, max8997_battery_extcon_evt_stop_work, charger); > if (ret) { > diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c > index d7f76835137f..a490f79131c1 100644 > --- a/drivers/usb/dwc3/drd.c > +++ b/drivers/usb/dwc3/drd.c > @@ -454,13 +454,8 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc) > * This device property is for kernel internal use only and > * is expected to be set by the glue code. > */ > - if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) { > - edev = extcon_get_extcon_dev(name); > - if (!edev) > - return ERR_PTR(-EPROBE_DEFER); > - > - return edev; > - } > + if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) > + return extcon_get_extcon_dev(name); > > /* > * Try to get an extcon device from the USB PHY controller's "port" > diff --git a/drivers/usb/phy/phy-omap-otg.c b/drivers/usb/phy/phy-omap-otg.c > index ee0863c6553e..6e6ef8c0bc7e 100644 > --- a/drivers/usb/phy/phy-omap-otg.c > +++ b/drivers/usb/phy/phy-omap-otg.c > @@ -95,8 +95,8 @@ static int omap_otg_probe(struct platform_device *pdev) > return -ENODEV; > > extcon = extcon_get_extcon_dev(config->extcon); > - if (!extcon) > - return -EPROBE_DEFER; > + if (IS_ERR(extcon)) > + return PTR_ERR(extcon); > > otg_dev = devm_kzalloc(&pdev->dev, sizeof(*otg_dev), GFP_KERNEL); > if (!otg_dev) > diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c > index 72f9001b0792..96c55eaf3f80 100644 > --- a/drivers/usb/typec/tcpm/fusb302.c > +++ b/drivers/usb/typec/tcpm/fusb302.c > @@ -1708,8 +1708,8 @@ static int fusb302_probe(struct i2c_client *client, > */ > if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) { > chip->extcon = extcon_get_extcon_dev(name); > - if (!chip->extcon) > - return -EPROBE_DEFER; > + if (IS_ERR(chip->extcon)) > + return PTR_ERR(chip->extcon); > } > > chip->vbus = devm_regulator_get(chip->dev, "vbus"); > > > -- Best Regards, Chanwoo Choi Samsung Electronics
