| Message ID | 20201221054323.247483-1-masahiroy@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | net: lantiq_etop: check the result of request_irq() | expand |
On Tue, Dec 22, 2020 at 12:26 AM Andrew Lunn <andrew@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 <ojeda@kernel.org> > > Signed-off-by: Masahiro Yamada <masahiroy@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. > > ch->dma.desc = 0; > > - request_irq(irq, ltq_etop_dma_irq, 0, "etop_rx", priv); > > + ret = request_irq(irq, ltq_etop_dma_irq, 0, "etop_rx", priv); > > + if (ret) { > > + netdev_err(dev, "failed to request irq\n"); > > + return ret; > > And here you need to cleanup ltq_dma_alloc_rx(). > > Andrew
On Tue, Dec 22, 2020 at 12:59:08AM +0900, Masahiro Yamada wrote: > On Tue, Dec 22, 2020 at 12:26 AM Andrew Lunn <andrew@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 <ojeda@kernel.org> > > > Signed-off-by: Masahiro Yamada <masahiroy@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
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; + } } 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; ch->dma.desc = 0; - request_irq(irq, ltq_etop_dma_irq, 0, "etop_rx", priv); + ret = request_irq(irq, ltq_etop_dma_irq, 0, "etop_rx", priv); + if (ret) { + netdev_err(dev, "failed to request irq\n"); + return ret; + } } ch->dma.irq = irq; }
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 <ojeda@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- drivers/net/ethernet/lantiq_etop.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)