net: Fix Tx hash bound checking

Fixes the lower and upper bounds when there are multiple TCs and
traffic is on the the same TC on the same device.

The lower bound is represented by 'qoffset' and the upper limit for
hash value is 'qcount + qoffset'. This gives a clean Rx to Tx queue
mapping when there are multiple TCs, as the queue indices for upper TCs
will be offset by 'qoffset'.

v2: Fixed commit description based on comments.

Fixes: 1b837d489e06 ("net: Revoke export for __skb_tx_hash, update it to just be static skb_tx_hash")
Fixes: eadec877ce9c ("net: Add support for subordinate traffic classes to netdev_pick_tx")
Signed-off-by: Amritha Nambiar <amritha.nambiar@intel.com>
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index e10bd680dc032cab54f1b5f4db99e485248fa1f4..c6c985fe7b1bcf784cedde2b2a86e26356471bee 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3076,6 +3076,8 @@ static u16 skb_tx_hash(const struct net_device *dev,
 
        if (skb_rx_queue_recorded(skb)) {
                hash = skb_get_rx_queue(skb);
+               if (hash >= qoffset)
+                       hash -= qoffset;
                while (unlikely(hash >= qcount))
                        hash -= qcount;
                return hash + qoffset;