HID: mcp2221: Set driver data before I2C adapter add

commit f2d4a5834638bbc967371b9168c0b481519f7c5e upstream.

The process of adding an I2C adapter can invoke I2C accesses on that new
adapter (see i2c_detect()).

Ensure we have set the adapter's driver data to avoid null pointer
dereferences in the xfer functions during the adapter add.

This has been noted in the past and the same fix proposed but not
completed. See:
https://lore.kernel.org/lkml/ef597e73-ed71-168e-52af-0d19b03734ac@vigem.de/

Signed-off-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sumanth Gavini <sumanth.gavini@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c
index 560eeec4035aa18036f0ae137aeca04c4660cb5a..b0dc0edc69c2faeae245ef58284cb3d82ec46673 100644 (file)
--- a/drivers/hid/hid-mcp2221.c
+++ b/drivers/hid/hid-mcp2221.c
@@ -879,12 +879,12 @@ static int mcp2221_probe(struct hid_device *hdev,
        snprintf(mcp->adapter.name, sizeof(mcp->adapter.name),
                        "MCP2221 usb-i2c bridge");
 
+       i2c_set_adapdata(&mcp->adapter, mcp);
        ret = i2c_add_adapter(&mcp->adapter);
        if (ret) {
                hid_err(hdev, "can't add usb-i2c adapter: %d\n", ret);
                goto err_i2c;
        }
-       i2c_set_adapdata(&mcp->adapter, mcp);
 
        /* Setup GPIO chip */
        mcp->gc = devm_kzalloc(&hdev->dev, sizeof(*mcp->gc), GFP_KERNEL);