Re: [patch] drivers/iommu: Fix iova DEBUG_PREEMPT splat

Cc: Joerg Roedel
2016-06-15T14:01:55Z

On Mon, Jun 13, 2016 at 02:56:36PM +0200, Mike Galbraith wrote:
>
> Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
> Cc: Joerg Roedel <joro@8bytes.org>
> ---
> drivers/iommu/iova.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> --- a/drivers/iommu/iova.c
> +++ b/drivers/iommu/iova.c
> @@ -749,8 +749,9 @@ static bool __iova_rcache_insert(struct
> bool can_insert = false;
> unsigned long flags;
>
> + local_irq_save(flags);
> cpu_rcache = this_cpu_ptr(rcache->cpu_rcaches);
> - spin_lock_irqsave(&cpu_rcache->lock, flags);
> + spin_lock(&cpu_rcache->lock);
>
> if (!iova_magazine_full(cpu_rcache->loaded)) {
> can_insert = true;
> @@ -812,8 +813,9 @@ static unsigned long __iova_rcache_get(s
> bool has_pfn = false;
> unsigned long flags;
>
> + local_irq_save(flags);
> cpu_rcache = this_cpu_ptr(rcache->cpu_rcaches);
> - spin_lock_irqsave(&cpu_rcache->lock, flags);
> + spin_lock(&cpu_rcache->lock);
>
> if (!iova_magazine_empty(cpu_rcache->loaded)) {
> has_pfn = true;

>From an earlier patch submitted by Sagar (Cc'ed) I think the right fix
is to just make the code use get_cpu_ptr/put_cpu_ptr instead of
this_cpu_ptr.

Joerg