From: Sean Hefty <sean.hefty@intel.com>
Date: Sat, 26 May 2012 00:24:08 +0000 (-0700)
Subject: rsocket: Fix hang in rrecv/rsend after disconnecting
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=87f678725a461861b9453cc205ae91a800630c14;p=~shefty%2Flibrdmacm.git

rsocket: Fix hang in rrecv/rsend after disconnecting

If a user calls rrecv() after a blocking rsocket has been disconnected,
it will hang.  This problem and the cause was reported by Sirdhar Samudrala
<samudrala@us.ibm.com>.  It can be reproduced by running netserver -f -D
using the rs-preload library.  A similar issue exists with rsend().

Fix this by not blocking on a CQ unless we're connected.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
---

diff --git a/src/rsocket.c b/src/rsocket.c
index 8cbd4252..1fcc4af4 100644
--- a/src/rsocket.c
+++ b/src/rsocket.c
@@ -937,6 +937,11 @@ static int rs_can_send(struct rsocket *rs)
 	       (rs->target_sgl[rs->target_sge].length != 0);
 }
 
+static int rs_conn_can_send(struct rsocket *rs)
+{
+	return rs_can_send(rs) || (rs->state != rs_connected);
+}
+
 static int rs_can_send_ctrl(struct rsocket *rs)
 {
 	return rs->ctrl_avail;
@@ -947,6 +952,11 @@ static int rs_have_rdata(struct rsocket *rs)
 	return (rs->rmsg_head != rs->rmsg_tail);
 }
 
+static int rs_conn_have_rdata(struct rsocket *rs)
+{
+	return rs_have_rdata(rs) || (rs->state != rs_connected);
+}
+
 static int rs_all_sends_done(struct rsocket *rs)
 {
 	return (rs->sqe_avail + rs->ctrl_avail) == rs->sq_size;
@@ -1007,7 +1017,7 @@ ssize_t rrecv(int socket, void *buf, size_t len, int flags)
 	}
 	fastlock_acquire(&rs->rlock);
 	if (!rs_have_rdata(rs)) {
-		ret = rs_process_cq(rs, rs_nonblocking(rs, flags), rs_have_rdata);
+		ret = rs_process_cq(rs, rs_nonblocking(rs, flags), rs_conn_have_rdata);
 		if (ret && errno != ECONNRESET)
 			goto out;
 	}
@@ -1111,9 +1121,14 @@ ssize_t rsend(int socket, const void *buf, size_t len, int flags)
 	fastlock_acquire(&rs->slock);
 	for (left = len; left; left -= xfer_size, buf += xfer_size) {
 		if (!rs_can_send(rs)) {
-			ret = rs_process_cq(rs, rs_nonblocking(rs, flags), rs_can_send);
+			ret = rs_process_cq(rs, rs_nonblocking(rs, flags),
+					    rs_conn_can_send);
 			if (ret)
 				break;
+			if (rs->state != rs_connected) {
+				ret = ERR(ECONNRESET);
+				break;
+			}
 		}
 
 		if (olen < left) {
@@ -1208,9 +1223,14 @@ static ssize_t rsendv(int socket, const struct iovec *iov, int iovcnt, int flags
 	fastlock_acquire(&rs->slock);
 	for (left = len; left; left -= xfer_size) {
 		if (!rs_can_send(rs)) {
-			ret = rs_process_cq(rs, rs_nonblocking(rs, flags), rs_can_send);
+			ret = rs_process_cq(rs, rs_nonblocking(rs, flags),
+					    rs_conn_can_send);
 			if (ret)
 				break;
+			if (rs->state != rs_connected) {
+				ret = ERR(ECONNRESET);
+				break;
+			}
 		}
 
 		if (olen < left) {