[7/7] messenger: con_work() is not really a loop

Commit Message

Alex Elder April 27, 2015, 5:13 p.m. UTC

In con_work(), a while(true) loop is used to contain a block of code.
The normal path through that code does *not* actually loop.  The only
time it loops is if a socket read or write operation returns -EAGAIN.
So the use of the loop control structure is a little misleading.

Restructure that block so it's *not* a loop, and use "goto" calls
rather than a loop to implement the control flow.

Signed-off-by: Alex Elder <[e-mail]>
---
 net/ceph/messenger.c | 84 +++++++++++++++++++++++++---------------------------
 1 file changed, 41 insertions(+), 43 deletions(-)

Patch

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index ec60c23..053c5f3 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2845,54 +2845,52 @@  static void con_work(struct work_struct *work)
 	struct ceph_connection *con = container_of(work, struct ceph_connection,
 						   work.work);
 	bool fault;
+	int ret;
 
 	mutex_lock(&con->mutex);
-	while (true) {
-		int ret;
-
-		if ((fault = con_sock_closed(con))) {
-			dout("%s: con %p SOCK_CLOSED\n", __func__, con);
-			break;
-		}
-		if (con_backoff(con)) {
-			dout("%s: con %p BACKOFF\n", __func__, con);
-			break;
-		}
-		if (con->state == CON_STATE_STANDBY) {
-			dout("%s: con %p STANDBY\n", __func__, con);
-			break;
-		}
-		if (con->state == CON_STATE_CLOSED) {
-			dout("%s: con %p CLOSED\n", __func__, con);
-			BUG_ON(con->sock);
-			break;
-		}
-		if (con->state == CON_STATE_PREOPEN) {
-			dout("%s: con %p PREOPEN\n", __func__, con);
-			BUG_ON(con->sock);
-		}
-
-		ret = try_read(con);
-		if (ret < 0) {
-			if (ret == -EAGAIN)
-				continue;
-			if (!con->error_msg)
-				con->error_msg = "socket error on read";
-			fault = true;
-			break;
-		}
+again:
+	fault = con_sock_closed(con);
+	if (fault) {
+		dout("%s: con %p SOCK_CLOSED\n", __func__, con);
+		goto done;
+	}
+	if (con_backoff(con)) {
+		dout("%s: con %p BACKOFF\n", __func__, con);
+		goto done;
+	}
+	if (con->state == CON_STATE_STANDBY) {
+		dout("%s: con %p STANDBY\n", __func__, con);
+		goto done;
+	}
+	if (con->state == CON_STATE_CLOSED) {
+		dout("%s: con %p CLOSED\n", __func__, con);
+		BUG_ON(con->sock);
+		goto done;
+	}
+	if (con->state == CON_STATE_PREOPEN) {
+		dout("%s: con %p PREOPEN\n", __func__, con);
+		BUG_ON(con->sock);
+	}
 
-		ret = try_write(con);
-		if (ret < 0) {
-			if (ret == -EAGAIN)
-				continue;
-			if (!con->error_msg)
-				con->error_msg = "socket error on write";
-			fault = true;
-		}
+	ret = try_read(con);
+	if (ret < 0) {
+		if (ret == -EAGAIN)
+			goto again;
+		if (!con->error_msg)
+			con->error_msg = "socket error on read";
+		fault = true;
+		goto done;
+	}
 
-		break;	/* If we make it to here, we're done */
+	ret = try_write(con);
+	if (ret < 0) {
+		if (ret == -EAGAIN)
+			goto again;
+		if (!con->error_msg)
+			con->error_msg = "socket error on write";
+		fault = true;
 	}
+done:
 	if (fault)
 		con_fault(con);
 	mutex_unlock(&con->mutex);