Messages in this thread | | | Subject | Re: [PATCH net-next] net: systemport: Do not block interrupts in TX reclaim | From | Florian Fainelli <> | Date | Fri, 24 Jan 2020 17:42:37 -0800 |
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On 1/24/2020 5:35 PM, Eric Dumazet wrote: > > > On 1/24/20 3:59 PM, Florian Fainelli wrote: >> There is no need to disable interrupts with a spin_lock_irqsave() in >> bcm_sysport_tx_poll() since we are in softIRQ context already. Leave >> interrupts enabled, thus giving a chance for the RX interrupts to be >> processed. >> >> This now makes bcm_sysport_tx_reclaim() equivalent to >> bcm_sysport_tx_clean(), thus remove the former, and make >> bcm_sysport_tx_reclaim_all() to use the latter. >> >> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> >> --- >> drivers/net/ethernet/broadcom/bcmsysport.c | 30 ++++++---------------- >> 1 file changed, 8 insertions(+), 22 deletions(-) >> >> diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c >> index f07ac0e0af59..dfff0657ce8f 100644 >> --- a/drivers/net/ethernet/broadcom/bcmsysport.c >> +++ b/drivers/net/ethernet/broadcom/bcmsysport.c >> @@ -925,26 +925,6 @@ static unsigned int __bcm_sysport_tx_reclaim(struct bcm_sysport_priv *priv, >> return pkts_compl; >> } >> >> -/* Locked version of the per-ring TX reclaim routine */ >> -static unsigned int bcm_sysport_tx_reclaim(struct bcm_sysport_priv *priv, >> - struct bcm_sysport_tx_ring *ring) >> -{ >> - struct netdev_queue *txq; >> - unsigned int released; >> - unsigned long flags; >> - >> - txq = netdev_get_tx_queue(priv->netdev, ring->index); >> - >> - spin_lock_irqsave(&ring->lock, flags); >> - released = __bcm_sysport_tx_reclaim(priv, ring); >> - if (released) >> - netif_tx_wake_queue(txq); >> - >> - spin_unlock_irqrestore(&ring->lock, flags); >> - >> - return released; >> -} >> - >> /* Locked version of the per-ring TX reclaim, but does not wake the queue */ >> static void bcm_sysport_tx_clean(struct bcm_sysport_priv *priv, >> struct bcm_sysport_tx_ring *ring) >> @@ -960,9 +940,15 @@ static int bcm_sysport_tx_poll(struct napi_struct *napi, int budget) >> { >> struct bcm_sysport_tx_ring *ring = >> container_of(napi, struct bcm_sysport_tx_ring, napi); >> + struct bcm_sysport_priv *priv = ring->priv; >> unsigned int work_done = 0; >> >> - work_done = bcm_sysport_tx_reclaim(ring->priv, ring); >> + spin_lock(&ring->lock); >> + work_done = __bcm_sysport_tx_reclaim(priv, ring); >> + if (work_done) >> + netif_tx_wake_queue(netdev_get_tx_queue(priv->netdev, >> + ring->index)); >> + spin_unlock(&ring->lock); >> >> if (work_done == 0) { >> napi_complete(napi); >> @@ -984,7 +970,7 @@ static void bcm_sysport_tx_reclaim_all(struct bcm_sysport_priv *priv) >> unsigned int q; >> >> for (q = 0; q < priv->netdev->num_tx_queues; q++) >> - bcm_sysport_tx_reclaim(priv, &priv->tx_rings[q]); >> + bcm_sysport_tx_clean(priv, &priv->tx_rings[q]); >> } >> >> static int bcm_sysport_poll(struct napi_struct *napi, int budget) >> > > I am a bit confused by this patch, the changelog mixes hard and soft irqs. > > This driver seems to call bcm_sysport_tx_reclaim_all() from hard irq handler > (INTRL2_0_TX_RING_FULL condition) > > So it looks you need to acquire ring->lock with some _irqsave() variant when > bcm_sysport_tx_poll() is running (from BH context)
You are right, I completely missed that path and the very reason why this is spin_lock_irqsave() in the first place... time to get some sleep.
Thanks! -- Florian
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