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SubjectRe: [PATCH v2] net: stmmac: only enable DMA interrupts when ready
On Thu, Feb 24, 2022 at 01:53:33PM +0100, Denis Kirjanov wrote:
> 2/24/22 14:38, Vincent Whitchurch пишет:
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > index 6708ca2aa4f7..43978558d6c0 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > @@ -2260,6 +2260,23 @@ static void stmmac_stop_tx_dma(struct stmmac_priv *priv, u32 chan)
> > stmmac_stop_tx(priv, priv->ioaddr, chan);
> > }
> >
> > +static void stmmac_enable_all_dma_irq(struct stmmac_priv *priv)
> > +{
> > + u32 rx_channels_count = priv->plat->rx_queues_to_use;
> > + u32 tx_channels_count = priv->plat->tx_queues_to_use;
> > + u32 dma_csr_ch = max(rx_channels_count, tx_channels_count);
> > + u32 chan;
> > +
> > + for (chan = 0; chan < dma_csr_ch; chan++) {
> > + struct stmmac_channel *ch = &priv->channel[chan];
> > + unsigned long flags;
> > +
> > + spin_lock_irqsave(&ch->lock, flags);
> > + stmmac_enable_dma_irq(priv, priv->ioaddr, chan, 1, 1);
> > + spin_unlock_irqrestore(&ch->lock, flags);
> > + }
> > +}
> > +
> > /**
> > * stmmac_start_all_dma - start all RX and TX DMA channels
> > * @priv: driver private structure
> > @@ -2902,8 +2919,10 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
> > stmmac_axi(priv, priv->ioaddr, priv->plat->axi);
> >
> > /* DMA CSR Channel configuration */
> > - for (chan = 0; chan < dma_csr_ch; chan++)
> > + for (chan = 0; chan < dma_csr_ch; chan++) {
> > stmmac_init_chan(priv, priv->ioaddr, priv->plat->dma_cfg, chan);
> Did you miss to take a channel lock?

I didn't add it on purpose. At this point during initialization there
is no-one who can race with the register write in
stmmac_disable_dma_irq(). The call to stmmac_init_chan() (in the
existing code) writes the same register without the lock.

> > + stmmac_disable_dma_irq(priv, priv->ioaddr, chan, 1, 1);
> > + }
> >

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