> The Multi-MSI interrupt handler doesn't clear the DMA error interrupts, > and this leads to interrupt storms when one of these interrupts starts > firing : > > - The RBU (rx buff unav) which triggers under high traffic load > > This triggers easily with iperf3 and small udp packets, and shows > when running the netpoll kselftest > > - The RPS (rx process stop) which triggers when we stop the DMA RX. > > This one shows when restarting the RX logic without doing a down/up > cycle, like when attaching an XDP program. The XSK kselftests > triggers it. > > Let's make sure we clear these interrupts for multi-MSI cases. It's > already properly done for the single-chan interrupt, and for that > introduce an "ERR" DMA dir, as we don't want to touch the RI/TI bits > when handling these interrupts. > > To avoid duplication, the DMA TX error handling is factored out in a > dedicated helper (in the same commit to ease backporting). > > Both of the above storms have been found on dwmac-motorcomm (YT8601), > and are triggered by the xdp.py, xsk_reconfig.py, xdp_features.py, > ring_reconfig.py and netpoll_basic kernel selftests. > > This seems to only affect dwmac4, there's no multi-msi mode on > dwmac1000, and on dwxgmac these interrupts are masked as of today. > > Fixes: 6ccf12ae111e ("net: stmmac: use interrupt mode INTM=1 for multi-MSI") > Signed-off-by: Maxime Chevallier Reviewed-by: Lorenzo Bianconi > --- > drivers/net/ethernet/stmicro/stmmac/common.h | 1 + > .../net/ethernet/stmicro/stmmac/dwmac4_dma.h | 5 ++ > .../net/ethernet/stmicro/stmmac/dwmac4_lib.c | 2 + > .../net/ethernet/stmicro/stmmac/stmmac_main.c | 46 +++++++++++++------ > 4 files changed, 40 insertions(+), 14 deletions(-) > > diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h > index c74bc7c9750e..a972bee66504 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/common.h > +++ b/drivers/net/ethernet/stmicro/stmmac/common.h > @@ -382,6 +382,7 @@ enum dma_irq_dir { > DMA_DIR_RX = 0x1, > DMA_DIR_TX = 0x2, > DMA_DIR_RXTX = 0x3, > + DMA_DIR_ERR = 0x4, > }; > > enum request_irq_err { > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h > index 43b036d4e95b..a7caac3c98e6 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h > @@ -173,6 +173,11 @@ static inline u32 dma_chanx_base_addr(const struct dwmac4_addrs *addrs, > DMA_CHAN_STATUS_TI | \ > DMA_CHAN_STATUS_MSK_COMMON) > > +#define DMA_CHAN_STATUS_MSK_ERR (DMA_CHAN_STATUS_AIS | \ > + DMA_CHAN_STATUS_FBE | \ > + DMA_CHAN_STATUS_RPS | \ > + DMA_CHAN_STATUS_RBU) > + > int dwmac4_dma_reset(void __iomem *ioaddr); > void dwmac4_enable_dma_irq(struct stmmac_priv *priv, void __iomem *ioaddr, > u32 chan, bool rx, bool tx); > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c > index a0249715fafa..02aa1a3dd1e2 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c > @@ -150,6 +150,8 @@ int dwmac4_dma_interrupt(struct stmmac_priv *priv, void __iomem *ioaddr, > intr_status &= DMA_CHAN_STATUS_MSK_RX; > else if (dir == DMA_DIR_TX) > intr_status &= DMA_CHAN_STATUS_MSK_TX; > + else if (dir == DMA_DIR_ERR) > + intr_status &= DMA_CHAN_STATUS_MSK_ERR; > > /* ABNORMAL interrupts */ > if (unlikely(intr_status & DMA_CHAN_STATUS_AIS)) { > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > index 9ded31150fbe..2068b57df8d5 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > @@ -3141,6 +3141,16 @@ static int stmmac_napi_check(struct stmmac_priv *priv, u32 chan, u32 dir) > return status; > } > > +static void stmmac_dma_tx_error(struct stmmac_priv *priv, u32 chan, int status) > +{ > + if (unlikely(status & tx_hard_error_bump_tc)) { > + /* Try to bump up the dma threshold on this failure */ > + stmmac_bump_dma_threshold(priv, chan); > + } else if (unlikely(status == tx_hard_error)) { > + stmmac_tx_err(priv, chan); > + } > +} > + > /** > * stmmac_dma_interrupt - DMA ISR > * @priv: driver private structure > @@ -3165,13 +3175,24 @@ static void stmmac_dma_interrupt(struct stmmac_priv *priv) > status[chan] = stmmac_napi_check(priv, chan, > DMA_DIR_RXTX); > > - for (chan = 0; chan < tx_channel_count; chan++) { > - if (unlikely(status[chan] & tx_hard_error_bump_tc)) { > - /* Try to bump up the dma threshold on this failure */ > - stmmac_bump_dma_threshold(priv, chan); > - } else if (unlikely(status[chan] == tx_hard_error)) { > - stmmac_tx_err(priv, chan); > - } > + for (chan = 0; chan < tx_channel_count; chan++) > + stmmac_dma_tx_error(priv, chan, status[chan]); > +} > + > +static void stmmac_dma_err_interrupt(struct stmmac_priv *priv) > +{ > + u8 tx_channel_count = priv->plat->tx_queues_to_use; > + u8 channels_to_check = max(priv->plat->rx_queues_to_use, > + tx_channel_count); > + int status; > + u8 chan; > + > + for (chan = 0; chan < channels_to_check; chan++) { > + status = stmmac_dma_interrupt_status(priv, priv->ioaddr, > + &priv->xstats, chan, > + DMA_DIR_ERR); > + if (chan < tx_channel_count) > + stmmac_dma_tx_error(priv, chan, status); > } > } > > @@ -6466,6 +6487,9 @@ static irqreturn_t stmmac_mac_interrupt(int irq, void *dev_id) > /* To handle Common interrupts */ > stmmac_common_interrupt(priv); > > + if (priv->plat->core_type == DWMAC_CORE_GMAC4) > + stmmac_dma_err_interrupt(priv); > + > return IRQ_HANDLED; > } > > @@ -6500,13 +6524,7 @@ static irqreturn_t stmmac_msi_intr_tx(int irq, void *data) > return IRQ_HANDLED; > > status = stmmac_napi_check(priv, chan, DMA_DIR_TX); > - > - if (unlikely(status & tx_hard_error_bump_tc)) { > - /* Try to bump up the dma threshold on this failure */ > - stmmac_bump_dma_threshold(priv, chan); > - } else if (unlikely(status == tx_hard_error)) { > - stmmac_tx_err(priv, chan); > - } > + stmmac_dma_tx_error(priv, chan, status); > > return IRQ_HANDLED; > } > -- > 2.56.0 >