[PATCH v1 1/2] gpiolib: Never return internal error codes to user space

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

Currently it's possible that character device interface may return
the error codes which are not supposed to be seen by user space.
In this case it's EPROBE_DEFER.

Wrap it to return -ENODEV instead as sysfs does.

Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 61f922db7221 ("gpio: userspace ABI for reading GPIO line events")
Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Reported-by: Suresh Balakrishnan <suresh.balakrishnan@xxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
 drivers/gpio/gpiolib-cdev.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 1631727bf0da..1d8f66880d63 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -331,8 +331,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 		}
 
 		ret = gpiod_request(desc, lh->label);
-		if (ret)
+		if (ret) {
+			if (ret == -EPROBE_DEFER)
+				ret = -ENODEV;
 			goto out_free_lh;
+		}
 		lh->descs[i] = desc;
 		linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
 
@@ -1379,8 +1382,11 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
 		}
 
 		ret = gpiod_request(desc, lr->label);
-		if (ret)
+		if (ret) {
+			if (ret == -EPROBE_DEFER)
+				ret = -ENODEV;
 			goto out_free_linereq;
+		}
 
 		lr->lines[i].desc = desc;
 		flags = gpio_v2_line_config_flags(lc, i);
@@ -1765,8 +1771,11 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	}
 
 	ret = gpiod_request(desc, le->label);
-	if (ret)
+	if (ret) {
+		if (ret == -EPROBE_DEFER)
+			ret = -ENODEV;
 		goto out_free_le;
+	}
 	le->desc = desc;
 	le->eflags = eflags;
 
-- 
2.30.2