[S390] qdio: fix broken pointer in case of CONFIG_DEBUG_FS is disabled

If CONFIG_DEBUG_FS is disabled debugfs_create_file returns -ENODEV instead
of zero. Since the return value is stored and used at shutdown to remove
existing entries an OOPS may be triggered.

Add a check of the debugfs_create_file return value and in case of an error
set the entry to NULL so it will be ignored at shutdown.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/s390/cio/qdio_debug.c b/drivers/s390/cio/qdio_debug.c
index f8a3b6967f69..da7afb04e71f 100644
--- a/drivers/s390/cio/qdio_debug.c
+++ b/drivers/s390/cio/qdio_debug.c
@@ -169,6 +169,8 @@ static void setup_debugfs_entry(struct qdio_q *q, struct ccw_device *cdev)
                  q->nr);
         debugfs_queues[i] = debugfs_create_file(name, S_IFREG | S_IRUGO | S_IWUSR,
                                                 debugfs_root, q, &debugfs_fops);
+        if (IS_ERR(debugfs_queues[i]))
+                debugfs_queues[i] = NULL;
 }
 
 void qdio_setup_debug_entries(struct qdio_irq *irq_ptr, struct ccw_device *cdev)