parport: quickfix the proc registration bug

Ideally we should have a directory of drivers and a link to the 'active'
driver. For now just show the first device which is effectively the existing
semantics without a warning.

This is an update on the original buggy patch that I then forgot to
resubmit. Confusingly it was proposed by Red Hat, written by Etched Pixels
fixed and submitted by Intel ...

Resolves-Bug: http://bugzilla.kernel.org/show_bug.cgi?id=9749
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 14 insertions, 3 deletions

diff --git a/drivers/parport/share.c b/drivers/parport/share.c
index 0ebca450ed29..dffa5d4fb298 100644
--- a/drivers/parport/share.c
+++ b/drivers/parport/share.c
@@ -614,7 +614,10 @@ parport_register_device(struct parport *port, const char *name,
          * pardevice fields. -arca
          */
         port->ops->init_state(tmp, tmp->state);
-        parport_device_proc_register(tmp);
+        if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
+                port->proc_device = tmp;
+                parport_device_proc_register(tmp);
+        }
         return tmp;
 
  out_free_all:
@@ -646,10 +649,14 @@ void parport_unregister_device(struct pardevice *dev)
         }
 #endif
 
-        parport_device_proc_unregister(dev);
-
         port = dev->port->physport;
 
+        if (port->proc_device == dev) {
+                port->proc_device = NULL;
+                clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
+                parport_device_proc_unregister(dev);
+        }
+
         if (port->cad == dev) {
                 printk(KERN_DEBUG "%s: %s forgot to release port\n",
                        port->name, dev->name);
diff --git a/include/linux/parport.h b/include/linux/parport.h
index e1f83c5065c5..38a423ed3c01 100644
--- a/include/linux/parport.h
+++ b/include/linux/parport.h
@@ -324,6 +324,10 @@ struct parport {
         int spintime;
         atomic_t ref_count;
 
+        unsigned long devflags;
+#define PARPORT_DEVPROC_REGISTERED      0
+        struct pardevice *proc_device;  /* Currently register proc device */
+
         struct list_head full_list;
         struct parport *slaves[3];
 };