xen: Use evtchn_type_t as a type for event channels

Make event channel functions pass event channel port using
evtchn_port_t type. It eliminates signed <-> unsigned conversion.

Signed-off-by: Yan Yankovskyi <yyankovskyi@gmail.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20200323152343.GA28422@kbp1-lhp-F74019
Signed-off-by: Juergen Gross <jgross@suse.com>
diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index 052b55a..6e0b1dd 100644
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -83,7 +83,7 @@ struct per_user_data {
 struct user_evtchn {
 	struct rb_node node;
 	struct per_user_data *user;
-	unsigned port;
+	evtchn_port_t port;
 	bool enabled;
 };
 
@@ -138,7 +138,8 @@ static void del_evtchn(struct per_user_data *u, struct user_evtchn *evtchn)
 	kfree(evtchn);
 }
 
-static struct user_evtchn *find_evtchn(struct per_user_data *u, unsigned port)
+static struct user_evtchn *find_evtchn(struct per_user_data *u,
+				       evtchn_port_t port)
 {
 	struct rb_node *node = u->evtchns.rb_node;
 
@@ -163,7 +164,7 @@ static irqreturn_t evtchn_interrupt(int irq, void *data)
 	struct per_user_data *u = evtchn->user;
 
 	WARN(!evtchn->enabled,
-	     "Interrupt for port %d, but apparently not enabled; per-user %p\n",
+	     "Interrupt for port %u, but apparently not enabled; per-user %p\n",
 	     evtchn->port, u);
 
 	disable_irq_nosync(irq);
@@ -286,7 +287,7 @@ static ssize_t evtchn_write(struct file *file, const char __user *buf,
 	mutex_lock(&u->bind_mutex);
 
 	for (i = 0; i < (count/sizeof(evtchn_port_t)); i++) {
-		unsigned port = kbuf[i];
+		evtchn_port_t port = kbuf[i];
 		struct user_evtchn *evtchn;
 
 		evtchn = find_evtchn(u, port);
@@ -361,7 +362,7 @@ static int evtchn_resize_ring(struct per_user_data *u)
 	return 0;
 }
 
-static int evtchn_bind_to_user(struct per_user_data *u, int port)
+static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port)
 {
 	struct user_evtchn *evtchn;
 	struct evtchn_close close;
@@ -423,7 +424,7 @@ static void evtchn_unbind_from_user(struct per_user_data *u,
 
 static DEFINE_PER_CPU(int, bind_last_selected_cpu);
 
-static void evtchn_bind_interdom_next_vcpu(int evtchn)
+static void evtchn_bind_interdom_next_vcpu(evtchn_port_t evtchn)
 {
 	unsigned int selected_cpu, irq;
 	struct irq_desc *desc;