netdev - Re: [PATCH net v2] ice: Unregister netdev and devlink

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Date: Tue, 20 Jun 2023 09:55:41 +0200
From: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
To: Jiri Pirko <jiri@...nulli.us>
CC: Petr Oros <poros@...hat.com>, <netdev@...r.kernel.org>,
	<jesse.brandeburg@...el.com>, <anthony.l.nguyen@...el.com>,
	<davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
	<pabeni@...hat.com>, <michal.swiatkowski@...ux.intel.com>,
	<jacob.e.keller@...el.com>, <intel-wired-lan@...ts.osuosl.org>,
	<linux-kernel@...r.kernel.org>, <pmenzel@...gen.mpg.de>
Subject: Re: [PATCH net v2] ice: Unregister netdev and devlink_port only once

On Mon, Jun 19, 2023 at 05:07:21PM +0200, Jiri Pirko wrote:
> Mon, Jun 19, 2023 at 12:58:13PM CEST, poros@...hat.com wrote:
> >Since commit 6624e780a577fc ("ice: split ice_vsi_setup into smaller
> >functions") ice_vsi_release does things twice. There is unregister
> >netdev which is unregistered in ice_deinit_eth also.
> 
> You need to describe more relationship between ice_vsi_release() and
> ice_deinit_eth(). From a quick look, I don't see that ice_deinit_eth()
> is always called before/afeter ice_vsi_release().
> 

Only relation between them is that they both are called on .remove() pci
callback. Clearly ice_vsi_release() should not be cleaning up stuff that
ice_init_eth() has brought up. I was staring at the code and jumping
around these flows and fix seems reasonable.

> Ice init/release flows are very hard to follow :/
> 
> 
> >
> >It also unregisters the devlink_port twice which is also unregistered
> >in ice_deinit_eth(). This double deregistration is hidden because
> >devl_port_unregister ignores the return value of xa_erase.
> 
> This call for another patch, doesn't it? :)

+1 :)

> 
> 
> >
> >[   68.642167] Call Trace:
> >[   68.650385]  ice_devlink_destroy_pf_port+0xe/0x20 [ice]
> >[   68.655656]  ice_vsi_release+0x445/0x690 [ice]
> >[   68.660147]  ice_deinit+0x99/0x280 [ice]
> >[   68.664117]  ice_remove+0x1b6/0x5c0 [ice]
> >
> >[  171.103841] Call Trace:
> >[  171.109607]  ice_devlink_destroy_pf_port+0xf/0x20 [ice]
> >[  171.114841]  ice_remove+0x158/0x270 [ice]
> >[  171.118854]  pci_device_remove+0x3b/0xc0
> >[  171.122779]  device_release_driver_internal+0xc7/0x170
> >[  171.127912]  driver_detach+0x54/0x8c
> >[  171.131491]  bus_remove_driver+0x77/0xd1
> >[  171.135406]  pci_unregister_driver+0x2d/0xb0
> >[  171.139670]  ice_module_exit+0xc/0x55f [ice]
> >
> >Fixes: 6624e780a577 ("ice: split ice_vsi_setup into smaller functions")
> >Signed-off-by: Petr Oros <poros@...hat.com>
> >---
> >v2: reword subject
> >
> >v1: https://lore.kernel.org/netdev/20230619084948.360128-1-poros@redhat.com/
> >---
> > drivers/net/ethernet/intel/ice/ice_lib.c | 27 ------------------------
> > 1 file changed, 27 deletions(-)
> >
> >diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
> >index 11ae0e41f518a1..284a1f0bfdb545 100644
> >--- a/drivers/net/ethernet/intel/ice/ice_lib.c
> >+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
> >@@ -3272,39 +3272,12 @@ int ice_vsi_release(struct ice_vsi *vsi)
> > 		return -ENODEV;
> > 	pf = vsi->back;
> > 
> >-	/* do not unregister while driver is in the reset recovery pending
> >-	 * state. Since reset/rebuild happens through PF service task workqueue,
> >-	 * it's not a good idea to unregister netdev that is associated to the
> >-	 * PF that is running the work queue items currently. This is done to
> >-	 * avoid check_flush_dependency() warning on this wq
> >-	 */
> >-	if (vsi->netdev && !ice_is_reset_in_progress(pf->state) &&
> >-	    (test_bit(ICE_VSI_NETDEV_REGISTERED, vsi->state))) {
> >-		unregister_netdev(vsi->netdev);
> >-		clear_bit(ICE_VSI_NETDEV_REGISTERED, vsi->state);
> >-	}
> >-
> >-	if (vsi->type == ICE_VSI_PF)
> >-		ice_devlink_destroy_pf_port(pf);
> >-
> > 	if (test_bit(ICE_FLAG_RSS_ENA, pf->flags))
> > 		ice_rss_clean(vsi);
> > 
> > 	ice_vsi_close(vsi);
> > 	ice_vsi_decfg(vsi);
> > 
> >-	if (vsi->netdev) {
> >-		if (test_bit(ICE_VSI_NETDEV_REGISTERED, vsi->state)) {
> >-			unregister_netdev(vsi->netdev);
> >-			clear_bit(ICE_VSI_NETDEV_REGISTERED, vsi->state);
> >-		}
> >-		if (test_bit(ICE_VSI_NETDEV_ALLOCD, vsi->state)) {
> >-			free_netdev(vsi->netdev);
> >-			vsi->netdev = NULL;
> >-			clear_bit(ICE_VSI_NETDEV_ALLOCD, vsi->state);
> >-		}
> >-	}
> >-
> > 	/* retain SW VSI data structure since it is needed to unregister and
> > 	 * free VSI netdev when PF is not in reset recovery pending state,\
> > 	 * for ex: during rmmod.
> >-- 
> >2.41.0
> >
> >
>