netdev - [PATCH net 2/2] ibmvnic: drop bad optimization in reuse_tx

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 30 Nov 2021 21:48:36 -0800
From:   Sukadev Bhattiprolu <sukadev@...ux.ibm.com>
To:     netdev@...r.kernel.org
Cc:     Brian King <brking@...ux.ibm.com>, Dany Madden <drt@...ux.ibm.com>,
        Rick Lindsley <ricklind@...ux.ibm.com>
Subject: [PATCH net 2/2] ibmvnic: drop bad optimization in reuse_tx_pools()

When trying to decide whether or not reuse existing rx/tx pools
we tried to allow a range of values for the pool parameters rather
than exact matches. This was intended to reuse the resources for
instance when switching between two VIO servers with different
default parameters.

But this optimization is incomplete and breaks when we try to
change the number of queues for instance. The optimization needs
to be updated, so drop it for now and simplify the code.

Fixes: bbd809305bc7 ("ibmvnic: Reuse tx pools when possible")
Reported-by: Dany Madden <drt@...ux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@...ux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 6df92a872f0f..0bb3911dd014 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -866,17 +866,9 @@ static bool reuse_tx_pools(struct ibmvnic_adapter *adapter)
 	old_mtu = adapter->prev_mtu;
 	new_mtu = adapter->req_mtu;
 
-	/* Require MTU to be exactly same to reuse pools for now */
-	if (old_mtu != new_mtu)
-		return false;
-
-	if (old_num_pools == new_num_pools && old_pool_size == new_pool_size)
-		return true;
-
-	if (old_num_pools < adapter->min_tx_queues ||
-	    old_num_pools > adapter->max_tx_queues ||
-	    old_pool_size < adapter->min_tx_entries_per_subcrq ||
-	    old_pool_size > adapter->max_tx_entries_per_subcrq)
+	if (old_mtu != new_mtu ||
+	    old_num_pools != new_num_pools ||
+	    old_pool_size != new_pool_size)
 		return false;
 
 	return true;
-- 
2.27.0