[PATCH net] netdevsim: don't overwrite read only ethtool parms

[PATCH net] netdevsim: don't overwrite read only ethtool parms

[Filip Pokryvka]

Ethtool ring feature has _max_pending attributes read-only.
Set only read-write attributes in nsim_set_ringparam.

This patch is useful, if netdevsim device is set-up using NetworkManager,
because NetworkManager sends 0 as MAX values, as it is pointless to
retrieve them in extra call, because they should be read-only. Then,
the device is left in incosistent state (value > MAX).

Fixes: a7fc6db099b5 ("netdevsim: support ethtool ring and coalesce settings")
Signed-off-by: Filip Pokryvka <fpokryvk@redhat.com>
---
 drivers/net/netdevsim/ethtool.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/netdevsim/ethtool.c b/drivers/net/netdevsim/ethtool.c
index b03a0513e..2e7c1cc16 100644
--- a/drivers/net/netdevsim/ethtool.c
+++ b/drivers/net/netdevsim/ethtool.c
@@ -77,7 +77,10 @@ static int nsim_set_ringparam(struct net_device *dev,
 {
 	struct netdevsim *ns = netdev_priv(dev);
 
-	memcpy(&ns->ethtool.ring, ring, sizeof(ns->ethtool.ring));
+	ns->ethtool.ring.rx_pending = ring->rx_pending;
+	ns->ethtool.ring.rx_jumbo_pending = ring->rx_jumbo_pending;
+	ns->ethtool.ring.rx_mini_pending = ring->rx_mini_pending;
+	ns->ethtool.ring.tx_pending = ring->tx_pending;
 	return 0;
 }
 
-- 
2.27.0

Re: [PATCH net] netdevsim: don't overwrite read only ethtool parms

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 10 Dec 2021 18:50:32 +0100 you wrote:
> Ethtool ring feature has _max_pending attributes read-only.
> Set only read-write attributes in nsim_set_ringparam.
> 
> This patch is useful, if netdevsim device is set-up using NetworkManager,
> because NetworkManager sends 0 as MAX values, as it is pointless to
> retrieve them in extra call, because they should be read-only. Then,
> the device is left in incosistent state (value > MAX).
> 
> [...]

Here is the summary with links:
  - [net] netdevsim: don't overwrite read only ethtool parms
    https://git.kernel.org/netdev/net/c/ee60e626d536

You are awesome, thank you!
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