Re: [PATCH net] fjes: Fix an error handling path in fjes_probe()

[Christophe JAILLET]

Le 21/12/2022 à 10:59, Michal Swiatkowski a écrit :
> On Tue, Dec 20, 2022 at 09:57:06PM +0100, Christophe JAILLET wrote:
> > A netif_napi_add() call is hidden in fjes_sw_init(). It should be undone
> > by a corresponding netif_napi_del() call in the error handling path of the
> > probe, as already done inthe remove function.
> >
> > Fixes: 265859309a76 ("fjes: NAPI polling function")
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >   drivers/net/fjes/fjes_main.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/fjes/fjes_main.c b/drivers/net/fjes/fjes_main.c
> > index 2513be6d4e11..01b4c9c6adbd 100644
> > --- a/drivers/net/fjes/fjes_main.c
> > +++ b/drivers/net/fjes/fjes_main.c
> > @@ -1370,7 +1370,7 @@ static int fjes_probe(struct platform_device *plat_dev)
> >   	adapter->txrx_wq = alloc_workqueue(DRV_NAME "/txrx", WQ_MEM_RECLAIM, 0);
> >   	if (unlikely(!adapter->txrx_wq)) {
> >   		err = -ENOMEM;
> > -		goto err_free_netdev;
> > +		goto err_del_napi;
> >   	}
> >   
> >   	adapter->control_wq = alloc_workqueue(DRV_NAME "/control",
> > @@ -1431,6 +1431,8 @@ static int fjes_probe(struct platform_device *plat_dev)
> >   	destroy_workqueue(adapter->control_wq);
> >   err_free_txrx_wq:
> >   	destroy_workqueue(adapter->txrx_wq);
> > +err_del_napi:
> > +	netif_napi_del(&adapter->napi);
> >   err_free_netdev:
> >   	free_netdev(netdev);
> >   err_out:
>
> Reviewed-by: Michal Swiatkowski <michal.swiatkowski@xxxxxxxxxxxxxxx>
>
> I wonder if it won't be better to have fjes_sw_deinit() instead or
> change fjes_sw_init to only netif_napi_add(). You know, to avoid another
> bug here when someone add sth to the fjes_sw_deinit(). This is only
> suggestion, patch looks fine.

hi,

based on Jakub's comment [1], free_netdev() already cleans up NAPIs (see 
[2]).

So would it make more sense to remove netif_napi_del() from the 
.remove() function instead?
The call looks useless to me now.

CJ

[1]: https://lore.kernel.org/all/20221221174043.1191996a@xxxxxxxxxx/
[2]: https://elixir.bootlin.com/linux/v6.2-rc1/source/net/core/dev.c#L10710

> > --
> > 2.34.1