On Tue, Dec 22, 2020 at 12:59:08AM +0900, Masahiro Yamada wrote:
> On Tue, Dec 22, 2020 at 12:26 AM Andrew Lunn <and...@lunn.ch> wrote:
> >
> > On Mon, Dec 21, 2020 at 02:43:23PM +0900, Masahiro Yamada wrote:
> > > The declaration of request_irq() in <linux/interrupt.h> is marked as
> > > __must_check.
> > >
> > > Without the return value check, I see the following warnings:
> > >
> > > drivers/net/ethernet/lantiq_etop.c: In function 'ltq_etop_hw_init':
> > > drivers/net/ethernet/lantiq_etop.c:273:4: warning: ignoring return value
> > > of 'request_irq', declared with attribute warn_unused_result
> > > [-Wunused-result]
> > > 273 | request_irq(irq, ltq_etop_dma_irq, 0, "etop_tx", priv);
> > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > drivers/net/ethernet/lantiq_etop.c:281:4: warning: ignoring return value
> > > of 'request_irq', declared with attribute warn_unused_result
> > > [-Wunused-result]
> > > 281 | request_irq(irq, ltq_etop_dma_irq, 0, "etop_rx", priv);
> > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >
> > > Reported-by: Miguel Ojeda <oj...@kernel.org>
> > > Signed-off-by: Masahiro Yamada <masahi...@kernel.org>
> > > ---
> > >
> > > drivers/net/ethernet/lantiq_etop.c | 13 +++++++++++--
> > > 1 file changed, 11 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/net/ethernet/lantiq_etop.c
> > > b/drivers/net/ethernet/lantiq_etop.c
> > > index 2d0c52f7106b..960494f9752b 100644
> > > --- a/drivers/net/ethernet/lantiq_etop.c
> > > +++ b/drivers/net/ethernet/lantiq_etop.c
> > > @@ -264,13 +264,18 @@ ltq_etop_hw_init(struct net_device *dev)
> > > for (i = 0; i < MAX_DMA_CHAN; i++) {
> > > int irq = LTQ_DMA_CH0_INT + i;
> > > struct ltq_etop_chan *ch = &priv->ch[i];
> > > + int ret;
> > >
> > > ch->idx = ch->dma.nr = i;
> > > ch->dma.dev = &priv->pdev->dev;
> > >
> > > if (IS_TX(i)) {
> > > ltq_dma_alloc_tx(&ch->dma);
> > > - request_irq(irq, ltq_etop_dma_irq, 0, "etop_tx",
> > > priv);
> > > + ret = request_irq(irq, ltq_etop_dma_irq, 0,
> > > "etop_tx", priv);
> > > + if (ret) {
> > > + netdev_err(dev, "failed to request irq\n");
> > > + return ret;
> >
> > You need to cleanup what ltq_dma_alloc_tx() did.
>
>
> Any failure from this function will roll back
> in the following paths:
>
> ltq_etop_hw_exit()
> -> ltq_etop_free_channel()
> -> ltq_dma_free()
>
>
> So, dma is freed anyway.
>
> One problem I see is,
> ltq_etop_hw_exit() frees all DMA channels,
> some of which may not have been allocated yet.
>
> If it is a bug, it is an existing bug.
>
>
> >
> > > + }
> > > } else if (IS_RX(i)) {
> > > ltq_dma_alloc_rx(&ch->dma);
> > > for (ch->dma.desc = 0; ch->dma.desc < LTQ_DESC_NUM;
> > > @@ -278,7 +283,11 @@ ltq_etop_hw_init(struct net_device *dev)
> > > if (ltq_etop_alloc_skb(ch))
> > > return -ENOMEM;
>
>
> This -ENOMEM does not roll back anything here.
>
> As stated above, dma_free_coherent() is called.
> The problem is, ltq_etop_hw_exit() rolls back too much.
>
> If your requirement is "this driver is completely wrong. Please rewrite it",
> sorry, I cannot (unless I am paid to do so).
>
> I am just following this driver's roll-back model.
>
> Please do not expect more to a person who
> volunteers to eliminate build warnings.
>
> Of course, if somebody volunteers to rewrite this driver correctly,
> that is appreciated.
Hi Hauke
Do you still have this hardware? Do you have time to take a look at
the cleanup code?
Thanks
Andrew
