Commit 415e69e6 authored Oct 01, 2009 by Michal Schmidt Committed by David S. Miller Oct 01, 2009

skge: use unique IRQ name



Most network drivers request their IRQ when the interface is activated.
skge does it in ->probe() instead, because it can work with two-port
cards where the two net_devices use the same IRQ. This works fine most
of the time, except in some situations when the interface gets renamed.
Consider this example:

1. modprobe skge
   The card is detected as eth0 and requests IRQ 17. Directory
   /proc/irq/17/eth0 is created.
2. There is an udev rule which says this interface should be called
   eth1, so udev renames eth0 -> eth1.
3. modprobe 8139too
   The Realtek card is detected as eth0. It will be using IRQ 17 too.
4. ip link set eth0 up
   Now 8139too requests IRQ 17.

The result is:
WARNING: at fs/proc/generic.c:590 proc_register ...
proc_dir_entry '17/eth0' already registered
...
And "ls /proc/irq/17" shows two subdirectories, both called eth0.

Fix it by using a unique name for skge's IRQ, based on the PCI address.
The naming from the example then looks like this:
$ grep skge /proc/interrupts
 17:        169   IO-APIC-fasteoi   skge@pci:0000:00:0a.0, eth0

irqbalance daemon will have to be taught to recognize "skge@" as an
Ethernet interrupt. This will be a one-liner addition in classify.c. I
will send a patch to irqbalance if this change is accepted.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 89e95a61

drivers/net/skge.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -3935,11 +3935,14 @@ static int __devinit skge_probe(struct pci_dev *pdev,
		#endif

		err = -ENOMEM;
		hw = kzalloc(sizeof(*hw), GFP_KERNEL);
		/* space for skge@pci:0000:04:00.0 */
		hw = kzalloc(sizeof(*hw) + strlen(DRV_NAME "@pci:" )
		+ strlen(pci_name(pdev)) + 1, GFP_KERNEL);
		if (!hw) {
		dev_err(&pdev->dev, "cannot allocate hardware struct\n");
		goto err_out_free_regions;
		}
		sprintf(hw->irq_name, DRV_NAME "@pci:%s", pci_name(pdev));

		hw->pdev = pdev;
		spin_lock_init(&hw->hw_lock);
		@@ -3974,7 +3977,7 @@ static int __devinit skge_probe(struct pci_dev *pdev,
		goto err_out_free_netdev;
		}

		err = request_irq(pdev->irq, skge_intr, IRQF_SHARED, dev->name, hw);
		err = request_irq(pdev->irq, skge_intr, IRQF_SHARED, hw->irq_name, hw);
		if (err) {
		dev_err(&pdev->dev, "%s: cannot assign irq %d\n",
		dev->name, pdev->irq);

drivers/net/skge.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -2423,6 +2423,8 @@ struct skge_hw {
		u16 phy_addr;
		spinlock_t phy_lock;
		struct tasklet_struct phy_task;

		char irq_name[0]; /* skge@pci:000:04:00.0 */
		};

		enum pause_control {

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