From: =?UTF-8?q?H=C3=A5kon=20Bugge?= <haakon.bugge@oracle.com>
Date: Tue, 22 Jun 2021 16:13:27 +0200
Subject: RDMA/cma: Fix incorrect Packet Lifetime calculation
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Patch-mainline: v5.14-rc1
Git-commit: e84045eab69c625bc0b0bf24d8e05bc65da1eed1
References: jsc#SLE-8449

An approximation for the PacketLifeTime is half the local ACK timeout.
The encoding for both timers are logarithmic.

If the local ACK timeout is set, but zero, it means the timer is
disabled. In this case, we choose the CMA_IBOE_PACKET_LIFETIME value,
since 50% of infinite makes no sense.

Before this commit, the PacketLifeTime became 255 if local ACK
timeout was zero (not running).

Fixed by explicitly testing for timeout being zero.

Fixes: e1ee1e62bec4 ("RDMA/cma: Use ACK timeout for RoCE packetLifeTime")
Link: https://lore.kernel.org/r/1624371207-26710-1-git-send-email-haakon.bugge@oracle.com
Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/core/cma.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -2970,8 +2970,10 @@ static int cma_resolve_iboe_route(struct
 	 * as a reasonable approximation for RoCE networks.
 	 */
 	mutex_lock(&id_priv->qp_mutex);
-	route->path_rec->packet_life_time = id_priv->timeout_set ?
-		id_priv->timeout - 1 : CMA_IBOE_PACKET_LIFETIME;
+	if (id_priv->timeout_set && id_priv->timeout)
+		route->path_rec->packet_life_time = id_priv->timeout - 1;
+	else
+		route->path_rec->packet_life_time = CMA_IBOE_PACKET_LIFETIME;
 	mutex_unlock(&id_priv->qp_mutex);
 
 	if (!route->path_rec->mtu) {