udlfb: fix some inconsistent NULL checking

In the current kernel, then kzalloc() can't fail for small allocations,
but if it did fail then we would have a NULL dereference in the error
handling.  Also in dlfb_usb_disconnect() if "info" were NULL then it
would cause an Oops inside the unregister_framebuffer() function but it
can't be NULL so let's remove that check.

Fixes: 68a958a915ca ("udlfb: handle unplug properly")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Bernie Thompson <bernie@plugable.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Wen Yang <wen.yang99@zte.com.cn>
[b.zolnierkie: added "Fixes:" tag]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c
index 070026a7e55a..1d034dddc556 100644
--- a/drivers/video/fbdev/udlfb.c
+++ b/drivers/video/fbdev/udlfb.c
@@ -1598,7 +1598,7 @@ static int dlfb_usb_probe(struct usb_interface *intf,
         dlfb = kzalloc(sizeof(*dlfb), GFP_KERNEL);
         if (!dlfb) {
                 dev_err(&intf->dev, "%s: failed to allocate dlfb\n", __func__);
-                goto error;
+                return -ENOMEM;
         }
 
         INIT_LIST_HEAD(&dlfb->deferred_free);
@@ -1703,7 +1703,7 @@ static int dlfb_usb_probe(struct usb_interface *intf,
 error:
         if (dlfb->info) {
                 dlfb_ops_destroy(dlfb->info);
-        } else if (dlfb) {
+        } else {
                 usb_put_dev(dlfb->udev);
                 kfree(dlfb);
         }
@@ -1730,12 +1730,10 @@ static void dlfb_usb_disconnect(struct usb_interface *intf)
         /* this function will wait for all in-flight urbs to complete */
         dlfb_free_urb_list(dlfb);
 
-        if (info) {
-                /* remove udlfb's sysfs interfaces */
-                for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
-                        device_remove_file(info->dev, &fb_device_attrs[i]);
-                device_remove_bin_file(info->dev, &edid_attr);
-        }
+        /* remove udlfb's sysfs interfaces */
+        for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
+                device_remove_file(info->dev, &fb_device_attrs[i]);
+        device_remove_bin_file(info->dev, &edid_attr);
 
         unregister_framebuffer(info);
 }