Driver core: allow certain drivers prohibit bind/unbind via sysfs

Platform drivers registered via platform_driver_probe() can be bound
to devices only once, upon registration, because discard their probe()
routines to save memory. Unbinding the driver through sysfs 'unbind'
leaves the device stranded and confuses users so let's not create
bind and unbind attributes for such drivers.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Éric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 973bf2ad4e0d3ae19eed9d91d53bef730a43d50a..63c143e54a5783656d9f0208acd3c9c4166ec4e2 100644 (file)
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -689,15 +689,19 @@ int bus_add_driver(struct device_driver *drv)
                printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n",
                        __func__, drv->name);
        }
-       error = add_bind_files(drv);
-       if (error) {
-               /* Ditto */
-               printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
-                       __func__, drv->name);
+
+       if (!drv->suppress_bind_attrs) {
+               error = add_bind_files(drv);
+               if (error) {
+                       /* Ditto */
+                       printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
+                               __func__, drv->name);
+               }
        }
 
        kobject_uevent(&priv->kobj, KOBJ_ADD);
        return 0;
+
 out_unregister:
        kfree(drv->p);
        drv->p = NULL;
@@ -720,7 +724,8 @@ void bus_remove_driver(struct device_driver *drv)
        if (!drv->bus)
                return;
 
-       remove_bind_files(drv);
+       if (!drv->suppress_bind_attrs)
+               remove_bind_files(drv);
        driver_remove_attrs(drv->bus, drv);
        driver_remove_file(drv, &driver_attr_uevent);
        klist_remove(&drv->p->knode_bus);

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index ed156a13aa40bfe40bc51d2d61ec899ec0059b1d..4fa954b07ac4ada384d27ffba6b293c22651febd 100644 (file)
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -521,11 +521,15 @@ int __init_or_module platform_driver_probe(struct platform_driver *drv,
 {
        int retval, code;
 
+       /* make sure driver won't have bind/unbind attributes */
+       drv->driver.suppress_bind_attrs = true;
+
        /* temporary section violation during probe() */
        drv->probe = probe;
        retval = code = platform_driver_register(drv);
 
-       /* Fixup that section violation, being paranoid about code scanning
+       /*
+        * Fixup that section violation, being paranoid about code scanning
         * the list of drivers in order to probe new devices.  Check to see
         * if the probe was successful, and make sure any forced probes of
         * new devices fail.

diff --git a/include/linux/device.h b/include/linux/device.h
index aca31bf7d8ed36ae03a07673fa95645bbe635d20..2ea3e49218129a6a4a4f314858ba0e0cbaa49691 100644 (file)
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -124,7 +124,9 @@ struct device_driver {
        struct bus_type         *bus;
 
        struct module           *owner;
-       const char              *mod_name;      /* used for built-in modules */
+       const char              *mod_name;      /* used for built-in modules */
+
+       bool suppress_bind_attrs;       /* disables bind/unbind via sysfs */
 
        int (*probe) (struct device *dev);
        int (*remove) (struct device *dev);