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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hariprasad Kelam <hkelam@marvell.com>,
        Sunil Kovvuri Goutham <sgoutham@marvell.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 081/111] octeontx2-af: fix infinite loop in unmapping NPC counter
Date:   Mon, 29 Mar 2021 09:58:29 +0200
Message-Id: <20210329075617.910112474@linuxfoundation.org>
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From: Hariprasad Kelam <hkelam@marvell.com>

[ Upstream commit 64451b98306bf1334a62bcd020ec92bdb4cb68db ]

unmapping npc counter works in a way by traversing all mcam
entries to find which mcam rule is associated with counter.
But loop cursor variable 'entry' is not incremented before
checking next mcam entry which resulting in infinite loop.

This in turn hogs the kworker thread forever and no other
mbox message is processed by AF driver after that.
Fix this by updating entry value before checking next
mcam entry.

Fixes: a958dd59f9ce ("octeontx2-af: Map or unmap NPC MCAM entry and counter")
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c
index 15f70273e29c..d82a519a0cd9 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c
@@ -1967,10 +1967,10 @@ int rvu_mbox_handler_npc_mcam_free_counter(struct rvu *rvu,
 		index = find_next_bit(mcam->bmap, mcam->bmap_entries, entry);
 		if (index >= mcam->bmap_entries)
 			break;
+		entry = index + 1;
 		if (mcam->entry2cntr_map[index] != req->cntr)
 			continue;
 
-		entry = index + 1;
 		npc_unmap_mcam_entry_and_cntr(rvu, mcam, blkaddr,
 					      index, req->cntr);
 	}
-- 
2.30.1