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Subject[PATCH] extcon: fix extcon_get_extcon_dev() error handling
The extcon_get_extcon_dev() function returns error pointers on error
and NULL when it's a -EPROBE_DEFER defer situation. There are eight
callers and only two of them handled this correctly. In the other
callers an error pointer return would lead to a crash.

What prevents crashes is that errors can only happen in the case of
a bug in the caller or if CONFIG_EXTCON is disabled. Six out of
eight callers use the Kconfig to either depend on or select
CONFIG_EXTCON. Thus the real life impact of these bugs is tiny.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
The two callers where the drivers can be built without CONFIG_EXTCON
are TYPEC_FUSB302 and CHARGER_MAX8997.

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.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 ++--
drivers/extcon/extcon-axp288.c | 4 ++--
8 files changed, 26 insertions(+), 31 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/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 7a2a17866a82..8594b59bd527 100644
--- a/drivers/usb/typec/tcpm/fusb302.c
+++ b/drivers/usb/typec/tcpm/fusb302.c
@@ -1706,8 +1706,8 @@ 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");
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 {
--
2.20.1
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