patch "USB: apple-mfi-fastcharge: don't probe unhandled devices" added to usb-linus

This is a note to let you know that I've just added the patch titled

USB: apple-mfi-fastcharge: don't probe unhandled devices

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 0cb686692fd200db12dcfb8231e793c1c98aec41 Mon Sep 17 00:00:00 2001
From: Bastien Nocera <[email protected]>
Date: Thu, 22 Oct 2020 09:55:21 -0400
Subject: USB: apple-mfi-fastcharge: don't probe unhandled devices

From: Bastien Nocera <[email protected]>

Contrary to the comment above the id table, we didn't implement a match function. This meant that every single Apple device that was already plugged in to the computer would have its device driver reprobed when the apple-mfi-fastcharge driver was loaded, eg. the SD card reader could be reprobed when the apple-mfi-fastcharge after pivoting root during boot up and the module became available.

Make sure that the driver probe isn't being run for unsupported devices by adding a match function that checks the product ID, in addition to the id_table checking the vendor ID.

---
 drivers/usb/misc/apple-mfi-fastcharge.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

index b403094a6b3a..579d8c84de42 100644
@@ -163,17 +163,23 @@ static const struct power_supply_desc apple_mfi_fc_desc = {
 	.property_is_writeable  = apple_mfi_fc_property_is_writeable
 };
 
+static bool mfi_fc_match(struct usb_device *udev)
+{
+	int idProduct;
+
+	idProduct = le16_to_cpu(udev->descriptor.idProduct);
+	/* See comment above mfi_fc_id_table[] */
+	return (idProduct >= 0x1200 && idProduct <= 0x12ff);
+}
+
 static int mfi_fc_probe(struct usb_device *udev)
 {
 	struct power_supply_config battery_cfg = {};
 	struct mfi_device *mfi = NULL;
-	int err, idProduct;
+	int err;
 
-	idProduct = le16_to_cpu(udev->descriptor.idProduct);
-	/* See comment above mfi_fc_id_table[] */
-	if (idProduct < 0x1200 || idProduct > 0x12ff) {
+	if (!mfi_fc_match(udev))
 		return -ENODEV;
-	}
 
 	mfi = kzalloc(sizeof(struct mfi_device), GFP_KERNEL);
 	if (!mfi) {

@@ -220,6 +226,7 @@ static struct usb_device_driver mfi_fc_driver = {
 	.probe =	mfi_fc_probe,
 	.disconnect =	mfi_fc_disconnect,
 	.id_table =	mfi_fc_id_table,
+	.match =	mfi_fc_match,
 	.generic_subclass = 1,
 };
 

2.29.1