NFC: fdp: Fix a signedness bug in fdp_nci_send_patch()

BugLink: https://bugs.launchpad.net/bugs/1873852

[ Upstream commit 0dcdf9f6 ]

The nci_conn_max_data_pkt_payload_size() function sometimes returns
-EPROTO so "max_size" needs to be signed for the error handling to
work.  We can make "payload_size" an int as well.

Fixes: a06347c0 ("NFC: Add Intel Fields Peak NFC solution driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

drivers/nfc/fdp/fdp.c

@@ -191,7 +191,7 @@ static int fdp_nci_send_patch(struct nci_dev *ndev, u8 conn_id, u8 type)
 	const struct firmware *fw;
 	struct sk_buff *skb;
 	unsigned long len;
-	u8 max_size, payload_size;
+	int max_size, payload_size;
 	int rc = 0;
 
 	if ((type == NCI_PATCH_TYPE_OTP && !info->otp_patch) ||
@@ -214,8 +214,7 @@ static int fdp_nci_send_patch(struct nci_dev *ndev, u8 conn_id, u8 type)
 
 	while (len) {
 
-		payload_size = min_t(unsigned long, (unsigned long) max_size,
-				     len);
+		payload_size = min_t(unsigned long, max_size, len);
 
 		skb = nci_skb_alloc(ndev, (NCI_CTRL_HDR_SIZE + payload_size),
 				    GFP_KERNEL);