thinkpad-acpi: don't leave ERR_PTR() pointers around

backlight_device_register returns ERR_PTR() in case of problems, and
the current code would leave that ERR_PTR in ibm_backlight_device.

The current code paths won't touch it in that situation, but that could
change.  Make sure to set ibm_backlight_device to NULL in the error
path.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index f78d27503925..b789ee8bc14e 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -6010,8 +6010,10 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
                                         TPACPI_BACKLIGHT_DEV_NAME, NULL, NULL,
                                         &ibm_backlight_data);
         if (IS_ERR(ibm_backlight_device)) {
+                int rc = PTR_ERR(ibm_backlight_device);
+                ibm_backlight_device = NULL;
                 printk(TPACPI_ERR "Could not register backlight device\n");
-                return PTR_ERR(ibm_backlight_device);
+                return rc;
         }
         vdbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_BRGHT,
                         "brightness is supported\n");