[PATCH 5/7] net/ncsi: Disable HWA mode when no channels are found

[Samuel Mendoza-Jonas]

From: Gavin Shan <gwshan at linux.vnet.ibm.com>

When there are no NCSI channels probed, HWA (Hardware Arbitration)
mode is enabled. It's not correct because HWA depends on the fact:
NCSI channels exist and all of them support HWA mode. This disables
HWA when no channels are probed.

Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
Signed-off-by: Samuel Mendoza-Jonas <sam at mendozajonas.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit 100ef01f3ea4badbee6479290a41f74abd0e523f)
---
 net/ncsi/ncsi-manage.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/ncsi/ncsi-manage.c b/net/ncsi/ncsi-manage.c
index 5bef2cb5a825..8a589e611225 100644
--- a/net/ncsi/ncsi-manage.c
+++ b/net/ncsi/ncsi-manage.c
@@ -991,12 +991,15 @@ static bool ncsi_check_hwa(struct ncsi_dev_priv *ndp)
 	struct ncsi_package *np;
 	struct ncsi_channel *nc;
 	unsigned int cap;
+	bool has_channel = false;
 
 	/* The hardware arbitration is disabled if any one channel
 	 * doesn't support explicitly.
 	 */
 	NCSI_FOR_EACH_PACKAGE(ndp, np) {
 		NCSI_FOR_EACH_CHANNEL(np, nc) {
+			has_channel = true;
+
 			cap = nc->caps[NCSI_CAP_GENERIC].cap;
 			if (!(cap & NCSI_CAP_GENERIC_HWA) ||
 			    (cap & NCSI_CAP_GENERIC_HWA_MASK) !=
@@ -1007,8 +1010,13 @@ static bool ncsi_check_hwa(struct ncsi_dev_priv *ndp)
 		}
 	}
 
-	ndp->flags |= NCSI_DEV_HWA;
-	return true;
+	if (has_channel) {
+		ndp->flags |= NCSI_DEV_HWA;
+		return true;
+	}
+
+	ndp->flags &= ~NCSI_DEV_HWA;
+	return false;
 }
 
 static int ncsi_enable_hwa(struct ncsi_dev_priv *ndp)
-- 
2.14.2