rfkill: allocate static minor

BugLink: https://bugs.launchpad.net/bugs/1859712
[ Upstream commit 8670b2b8b029a6650d133486be9d2ace146fd29a ]

udev has a feature of creating /dev/<node> device-nodes if it finds
a devnode:<node> modalias. This allows for auto-loading of modules that
provide the node. This requires to use a statically allocated minor
number for misc character devices.

However, rfkill uses dynamic minor numbers and prevents auto-loading
of the module. So allocate the next static misc minor number and use
it for rfkill.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Link: https://lore.kernel.org/r/20191024174042.19851-1-marcel@holtmann.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
index 3247a3dc7934893b586547a3dd830d2e63b43589..b06b75776a32f85fc5359f9683570e924c7b4b9e 100644 (file)
--- a/include/linux/miscdevice.h
+++ b/include/linux/miscdevice.h
@@ -57,6 +57,7 @@
 #define UHID_MINOR             239
 #define USERIO_MINOR           240
 #define VHOST_VSOCK_MINOR      241
+#define RFKILL_MINOR           242
 #define MISC_DYNAMIC_MINOR     255
 
 struct device;

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 2064c3a35ef84d4c54c065e8b54d524cdb407736..99a2e55b01cf33dca866ee9b83677f1aed421534 100644 (file)
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c
@@ -1312,10 +1312,12 @@ static const struct file_operations rfkill_fops = {
        .llseek         = no_llseek,
 };
 
+#define RFKILL_NAME "rfkill"
+
 static struct miscdevice rfkill_miscdev = {
-       .name   = "rfkill",
        .fops   = &rfkill_fops,
-       .minor  = MISC_DYNAMIC_MINOR,
+       .name   = RFKILL_NAME,
+       .minor  = RFKILL_MINOR,
 };
 
 static int __init rfkill_init(void)
@@ -1367,3 +1369,6 @@ static void __exit rfkill_exit(void)
        class_unregister(&rfkill_class);
 }
 module_exit(rfkill_exit);
+
+MODULE_ALIAS_MISCDEV(RFKILL_MINOR);
+MODULE_ALIAS("devname:" RFKILL_NAME);