[Intel-wired-lan] [PATCH net v2] ice: double lock on adev_mutex

[Intel-wired-lan] [PATCH net v2] ice: double lock on adev_mutex

[Michal Swiatkowski]

Call trace:
ice_set_channel() --> mutex_lock(adev_mutex)
ice_vsi_recfg_qs()
ice_pf_dcb_recfg()
ice_send_event_to_aux() --> another mutex_lock(adev_mutex)

This call trace is reached when user try to change queues amount using
ethtool:
$ ethtool -L enp24s0f0np0 tx 64 rx 32

Avoid double lock by unlocking after checking if RDMA is active.

Fixes: a49a2713f00e ("ice: Prevent set_channel from changing queues while RDMA active")
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Dave Ertman <david.m.ertman@intel.com>
---
v1 --> v2:
 * As mutex_unlock happens before other error handling there is no need
 to have ret variable, remove it

To be squash with:
https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20221219181803.1060129-1-david.m.ertman@intel.com/
---
 drivers/net/ethernet/intel/ice/ice_ethtool.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c
index 263d59929602..936f0e0c553d 100644
--- a/drivers/net/ethernet/intel/ice/ice_ethtool.c
+++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
@@ -3662,7 +3662,6 @@ static int ice_set_channels(struct net_device *dev, struct ethtool_channels *ch)
 	struct ice_pf *pf = vsi->back;
 	int new_rx = 0, new_tx = 0;
 	u32 curr_combined;
-	int ret = 0;
 
 	/* do not support changing channels in Safe Mode */
 	if (ice_is_safe_mode(pf)) {
@@ -3729,23 +3728,20 @@ static int ice_set_channels(struct net_device *dev, struct ethtool_channels *ch)
 	mutex_lock(&pf->adev_mutex);
 	if (pf->adev && pf->adev->dev.driver) {
 		netdev_err(dev, "Cannot change channels when RDMA is active\n");
-		ret = -EINVAL;
-		goto adev_unlock;
+		mutex_unlock(&pf->adev_mutex);
+		return -EINVAL;
 	}
+	mutex_unlock(&pf->adev_mutex);
 
 	ice_vsi_recfg_qs(vsi, new_rx, new_tx);
 
-	if (!netif_is_rxfh_configured(dev)) {
-		ret = ice_vsi_set_dflt_rss_lut(vsi, new_rx);
-		goto adev_unlock;
-	}
+	if (!netif_is_rxfh_configured(dev))
+		return ice_vsi_set_dflt_rss_lut(vsi, new_rx);
 
 	/* Update rss_size due to change in Rx queues */
 	vsi->rss_size = ice_get_valid_rss_size(&pf->hw, new_rx);
 
-adev_unlock:
-	mutex_unlock(&pf->adev_mutex);
-	return ret;
+	return 0;
 }
 
 /**
-- 
2.36.1

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Re: [Intel-wired-lan] [PATCH net v2] ice: double lock on adev_mutex

[G, GurucharanX]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Michal Swiatkowski
> Sent: Friday, January 13, 2023 11:35 AM
> To: intel-wired-lan@lists.osuosl.org
> Subject: [Intel-wired-lan] [PATCH net v2] ice: double lock on adev_mutex
> 
> Call trace:
> ice_set_channel() --> mutex_lock(adev_mutex)
> ice_vsi_recfg_qs()
> ice_pf_dcb_recfg()
> ice_send_event_to_aux() --> another mutex_lock(adev_mutex)
> 
> This call trace is reached when user try to change queues amount using
> ethtool:
> $ ethtool -L enp24s0f0np0 tx 64 rx 32
> 
> Avoid double lock by unlocking after checking if RDMA is active.
> 
> Fixes: a49a2713f00e ("ice: Prevent set_channel from changing queues while
> RDMA active")
> Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
> Reviewed-by: Dave Ertman <david.m.ertman@intel.com>
> ---
> v1 --> v2:
>  * As mutex_unlock happens before other error handling there is no need  to
> have ret variable, remove it
> 
> To be squash with:
> https://patchwork.ozlabs.org/project/intel-wired-
> lan/patch/20221219181803.1060129-1-david.m.ertman@intel.com/
> ---
>  drivers/net/ethernet/intel/ice/ice_ethtool.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 

Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
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