tap: Split out handling of EPOLLIN events

Currently, tap_handler_pas{st,ta}() check for EPOLLRDHUP, EPOLLHUP and
EPOLLERR events, then assume anything left is EPOLLIN.  We have some future
cases that may want to also handle EPOLLOUT, so in preparation explicitly
handle EPOLLIN, moving the logic to a subfunction.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 36 insertions, 14 deletions

diff --git a/tap.c b/tap.c
index 852d837..c8abc06 100644
--- a/tap.c
+++ b/tap.c
@@ -982,24 +982,17 @@ static void tap_sock_reset(struct ctx *c)
 }
 
 /**
- * tap_handler_passt() - Packet handler for AF_UNIX file descriptor
+ * tap_passt_input() - Handler for new data on the socket to qemu
  * @c:		Execution context
- * @events:	epoll events
  * @now:	Current timestamp
  */
-void tap_handler_passt(struct ctx *c, uint32_t events,
-		       const struct timespec *now)
+static void tap_passt_input(struct ctx *c, const struct timespec *now)
 {
 	static const char *partial_frame;
 	static ssize_t partial_len = 0;
 	ssize_t n;
 	char *p;
 
-	if (events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR)) {
-		tap_sock_reset(c);
-		return;
-	}
-
 	tap_flush_pools();
 
 	if (partial_len) {
@@ -1052,20 +1045,33 @@ void tap_handler_passt(struct ctx *c, uint32_t events,
 }
 
 /**
- * tap_handler_pasta() - Packet handler for /dev/net/tun file descriptor
+ * tap_handler_passt() - Event handler for AF_UNIX file descriptor
  * @c:		Execution context
  * @events:	epoll events
  * @now:	Current timestamp
  */
-void tap_handler_pasta(struct ctx *c, uint32_t events,
+void tap_handler_passt(struct ctx *c, uint32_t events,
 		       const struct timespec *now)
 {
+	if (events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR)) {
+		tap_sock_reset(c);
+		return;
+	}
+
+	if (events & EPOLLIN)
+		tap_passt_input(c, now);
+}
+
+/**
+ * tap_pasta_input() - Handler for new data on the socket to hypervisor
+ * @c:		Execution context
+ * @now:	Current timestamp
+ */
+static void tap_pasta_input(struct ctx *c, const struct timespec *now)
+{
 	ssize_t n, len;
 	int ret;
 
-	if (events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR))
-		die("Disconnect event on /dev/net/tun device, exiting");
-
 redo:
 	n = 0;
 
@@ -1103,6 +1109,22 @@ restart:
 }
 
 /**
+ * tap_handler_pasta() - Packet handler for /dev/net/tun file descriptor
+ * @c:		Execution context
+ * @events:	epoll events
+ * @now:	Current timestamp
+ */
+void tap_handler_pasta(struct ctx *c, uint32_t events,
+		       const struct timespec *now)
+{
+	if (events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR))
+		die("Disconnect event on /dev/net/tun device, exiting");
+
+	if (events & EPOLLIN)
+		tap_pasta_input(c, now);
+}
+
+/**
  * tap_sock_unix_open() - Create and bind AF_UNIX socket
  * @sock_path:	Socket path. If empty, set on return (UNIX_SOCK_PATH as prefix)
  *