[Xen-devel] Re: [PATCH] x86: check if desc->action is NULL when unbinding guest pirq

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 22/01/2010 08:01, "Cui, Dexuan" <dexuan.cui@xxxxxxxxx> wrote:

> Before igb PF driver is unloaded, dom0 doesn't unload igbvf driver
> automatically. When igb drver is unloaded, it invokes the
> PHYSDEVOP_manage_pci_remove hypercall to remove the VFs and xen frees the msi
> irqs by pci_cleanup_msi() -> ... -> dynamic_irq_cleanup() and sets the
> desc->action to NULL.
> igbvf driver knows the VF is disappearing via a hook ndo_stop() in dev_close()
> and tries to unbind the pirq and xen would crash as the desc->action
> is NULL now.
> The patch adds the checking for this.

Although I checked this in as c/s 20844, I now wonder what the
'desc->status|IRQ_DISABLED' is included for? (e.g., see below extract:)

+ if (unlikely((desc->status | IRQ_DISABLED) && (desc->action == NULL)))

Looks pointless: should this just be 'if(desc->action==NULL)'?

 -- Keir



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