Re: [PATCH] kvm/eventfd: fix the misleading comment in kvm_irqfd_assign

[Christian Borntraeger]

Am 29.11.21 um 04:43 schrieb Longpeng(Mike):
> From: Longpeng <longpeng2@xxxxxxxxxx>
>
> The comment above the invocation of vfs_poll() is misleading, move
> it to the right place.
I think that the current variant is better.
events is only used in that function to check for EPOLLIN, so the
assignment and the if belong together from a "what am I doing here" perspective.

> Fixes: 684a0b719ddb ("KVM: eventfd: Fix lock order inversion")
> Signed-off-by: Longpeng <longpeng2@xxxxxxxxxx>
> ---
>   virt/kvm/eventfd.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index 2ad013b..cd01814 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -406,12 +406,12 @@ bool __attribute__((weak)) kvm_arch_irqfd_route_changed(
>
>   	spin_unlock_irq(&kvm->irqfds.lock);
>
> +	events = vfs_poll(f.file, &irqfd->pt);
> +
>   	/*
>   	 * Check if there was an event already pending on the eventfd
>   	 * before we registered, and trigger it as if we didn't miss it.
>   	 */
> -	events = vfs_poll(f.file, &irqfd->pt);
> -
>   	if (events & EPOLLIN)
>   		schedule_work(&irqfd->inject);