3c503: Fix IRQ probing (b0cf4dfb) · Commits · 戴 / test

The driver attempts to select an IRQ for the NIC automatically by testing which of the supported IRQs are available and then probing each available IRQ with probe_irq_{on,off}(). There are obvious race conditions here, besides which: 1. The test for availability is done by passing a NULL handler, which now always returns -EINVAL, thus the device cannot be opened: <http://bugs.debian.org/566522 > 2. probe_irq_off() will report only the first ISA IRQ handled, potentially leading to a false negative. There was another bug that meant it ignored all error codes from request_irq() except -EBUSY, so it would 'succeed' despite this (possibly causing conflicts with other ISA devices). This was fixed by 'WARNING: some request_irq() failures ignored in el2_open()', which exposed bug 1. This patch: 1. Replaces the use of probe_irq_{on,off}() with a real interrupt handler 2. Adds a delay before checking the interrupt-seen flag 3. Disables interrupts on all failure paths 4. Distinguishes error codes from the second request_irq() call, consistently with the first Compile-tested only. Signed-off-by:

Ben Hutchings <ben@decadent.org.uk> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/3c503.c

+30 −12

Original line number	Diff line number	Diff line
		@@ -380,6 +380,12 @@ out:
		return retval;
		}

		static irqreturn_t el2_probe_interrupt(int irq, void *seen)
		{
		(bool )seen = true;
		return IRQ_HANDLED;
		}

		static int
		el2_open(struct net_device *dev)
		{
		@@ -391,23 +397,35 @@ el2_open(struct net_device *dev)

		outb(EGACFR_NORM, E33G_GACFR); /* Enable RAM and interrupts. */
		do {
		retval = request_irq(*irqp, NULL, 0, "bogus", dev);
		if (retval >= 0) {
		bool seen;

		retval = request_irq(*irqp, el2_probe_interrupt, 0,
		dev->name, &seen);
		if (retval == -EBUSY)
		continue;
		if (retval < 0)
		goto err_disable;

		/* Twinkle the interrupt, and check if it's seen. */
		unsigned long cookie = probe_irq_on();
		seen = false;
		smp_wmb();
		outb_p(0x04 << ((irqp == 9) ? 2 : irqp), E33G_IDCFR);
		outb_p(0x00, E33G_IDCFR);
		if (irqp == probe_irq_off(cookie) && / It's a good IRQ line! */
		((retval = request_irq(dev->irq = *irqp,
		eip_interrupt, 0,
		dev->name, dev)) == 0))
		break;
		} else {
		if (retval != -EBUSY)
		return retval;
		}
		msleep(1);
		free_irq(*irqp, el2_probe_interrupt);
		if (!seen)
		continue;

		retval = request_irq(dev->irq = *irqp, eip_interrupt, 0,
		dev->name, dev);
		if (retval == -EBUSY)
		continue;
		if (retval < 0)
		goto err_disable;
		} while (*++irqp);

		if (*irqp == 0) {
		err_disable:
		outb(EGACFR_IRQOFF, E33G_GACFR); /* disable interrupts. */
		return -EAGAIN;
		}

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