From: Karsten Graul kgraul@linux.ibm.com
[ Upstream commit 6889b36da78a21a312d8b462c1fa25a03c2ff192 ]
When there is no more send buffer space and at least 1 byte was already sent then return to user space. The wait is only done when no data was sent by the sendmsg() call. This fixes smc_tx_sendmsg() which tried to always send all user data and started to wait for free send buffer space when needed. During this wait the user space program was blocked in the sendmsg() call and hence not able to receive incoming data. When both sides were in such a situation then the connection stalled forever.
Signed-off-by: Karsten Graul kgraul@linux.ibm.com Signed-off-by: Ursula Braun ubraun@linux.ibm.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/smc/smc_tx.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c index 28361aef99825..f1f621675db01 100644 --- a/net/smc/smc_tx.c +++ b/net/smc/smc_tx.c @@ -163,12 +163,11 @@ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len) conn->local_tx_ctrl.prod_flags.urg_data_pending = 1;
if (!atomic_read(&conn->sndbuf_space) || conn->urg_tx_pend) { + if (send_done) + return send_done; rc = smc_tx_wait(smc, msg->msg_flags); - if (rc) { - if (send_done) - return send_done; + if (rc) goto out_err; - } continue; }