openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

3c503: Fix IRQ probing 

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 ab08999d60 '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>
This commit is contained in:
Ben Hutchings 2010-04-07 20:55:47 -07:00 committed by David S. Miller
parent e31d5a0594
commit b0cf4dfb7c
1 changed files with 30 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
drivers/net/3c503.c
View File

@ -380,6 +380,12 @@ el2_probe1(struct net_device *dev, int ioaddr)
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;
}