[PATCH AUTOSEL 4.14 077/130] rfkill: allocate static minor

Sasha Levin
2019-12-10T22:09:09Z

From: Marcel Holtmann <marcel@holtmann.org>

[ 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>
---
include/linux/miscdevice.h | 1 +
net/rfkill/core.c | 9 +++++++--
2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
index 4de703d9e21f0..5e1e50b8f8c47 100644
--- a/include/linux/miscdevice.h
+++ b/include/linux/miscdevice.h
@@ -56,6 +56,7 @@
#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 2064c3a35ef84..99a2e55b01cf3 100644
--- 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);
--
2.20.1