From 3f2e8d9f13246382fbda6f03178eef867a9bfbe2 Mon Sep 17 00:00:00 2001 From: Simon Kagstrom Date: Tue, 9 Feb 2010 23:38:25 +0000 Subject: [PATCH] via-velocity: Fix races on shared interrupts This patch fixes two potential races in the velocity driver: * Move the ACK and error handler to the interrupt handler. This fixes a potential race with shared interrupts when the other device interrupts before the NAPI poll handler has finished. As the velocity driver hasn't acked it's own interrupt, it will then steal the interrupt from the other device. * Use spin_lock_irqsave in velocity_poll. In the current code, the interrupt handler will deadlock if e.g., the NAPI poll handler is executing when an interrupt (for another device) comes in since it tries to take the already held lock. Also unlock the spinlock only after enabling the interrupt in velocity_poll. The error path is moved to the interrupt handler since this is where the ISR is checked now. Signed-off-by: Simon Kagstrom Signed-off-by: Anders Grafstrom Signed-off-by: David S. Miller --- drivers/net/via-velocity.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/drivers/net/via-velocity.c b/drivers/net/via-velocity.c index 54bafdab1f9d..317aa34b21cf 100644 --- a/drivers/net/via-velocity.c +++ b/drivers/net/via-velocity.c @@ -2148,16 +2148,9 @@ static int velocity_poll(struct napi_struct *napi, int budget) struct velocity_info *vptr = container_of(napi, struct velocity_info, napi); unsigned int rx_done; - u32 isr_status; - - spin_lock(&vptr->lock); - isr_status = mac_read_isr(vptr->mac_regs); - - /* Ack the interrupt */ - mac_write_isr(vptr->mac_regs, isr_status); - if (isr_status & (~(ISR_PRXI | ISR_PPRXI | ISR_PTXI | ISR_PPTXI))) - velocity_error(vptr, isr_status); + unsigned long flags; + spin_lock_irqsave(&vptr->lock, flags); /* * Do rx and tx twice for performance (taken from the VIA * out-of-tree driver). @@ -2167,13 +2160,12 @@ static int velocity_poll(struct napi_struct *napi, int budget) rx_done += velocity_rx_srv(vptr, budget - rx_done); velocity_tx_srv(vptr); - spin_unlock(&vptr->lock); - /* If budget not fully consumed, exit the polling mode */ if (rx_done < budget) { napi_complete(napi); mac_enable_int(vptr->mac_regs); } + spin_unlock_irqrestore(&vptr->lock, flags); return rx_done; } @@ -2203,10 +2195,17 @@ static irqreturn_t velocity_intr(int irq, void *dev_instance) return IRQ_NONE; } + /* Ack the interrupt */ + mac_write_isr(vptr->mac_regs, isr_status); + if (likely(napi_schedule_prep(&vptr->napi))) { mac_disable_int(vptr->mac_regs); __napi_schedule(&vptr->napi); } + + if (isr_status & (~(ISR_PRXI | ISR_PPRXI | ISR_PTXI | ISR_PPTXI))) + velocity_error(vptr, isr_status); + spin_unlock(&vptr->lock); return IRQ_HANDLED; -- 2.30.2