Messages in this thread | | | Date | Thu, 2 Nov 2017 18:33:50 +0100 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH v2] iommu/iova: Use raw_cpu_ptr() instead of get_cpu_ptr() for ->fq |
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On 2017-09-21 17:21:40 [+0200], Sebastian Andrzej Siewior wrote: > get_cpu_ptr() disabled preemption and returns the ->fq object of the > current CPU. raw_cpu_ptr() does the same except that it not disable > preemption which means the scheduler can move it to another CPU after it > obtained the per-CPU object. > In this case this is not bad because the data structure itself is > protected with a spin_lock. This change shouldn't matter however on RT > it does because the sleeping lock can't be accessed with disabled > preemption.
Did this make to your tree Jörg?
> Cc: Joerg Roedel <joro@8bytes.org> > Cc: iommu@lists.linux-foundation.org > Reported-by: vinadhy@gmail.com > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > --- > On 2017-09-19 11:41:19 [+0200], Joerg Roedel wrote: > > Hi Sebastian, > Hi Jörg, > > > I moved the flushing to driver/iommu/iova.c to share it with the Intel > > IOMMU and possibly other drivers too, so this patch does no longer apply > > to v4.14-rc1. Can you update the patch to these changes? > > Sure. > > v1…v2: move the change from amd_iommu.c to iova.c > > drivers/iommu/iova.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c > index 33edfa794ae9..b30900025c62 100644 > --- a/drivers/iommu/iova.c > +++ b/drivers/iommu/iova.c > @@ -570,7 +570,7 @@ void queue_iova(struct iova_domain *iovad, > unsigned long pfn, unsigned long pages, > unsigned long data) > { > - struct iova_fq *fq = get_cpu_ptr(iovad->fq); > + struct iova_fq *fq = raw_cpu_ptr(iovad->fq); > unsigned long flags; > unsigned idx; > > @@ -600,8 +600,6 @@ void queue_iova(struct iova_domain *iovad, > if (atomic_cmpxchg(&iovad->fq_timer_on, 0, 1) == 0) > mod_timer(&iovad->fq_timer, > jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT)); > - > - put_cpu_ptr(iovad->fq); > } > EXPORT_SYMBOL_GPL(queue_iova); > > -- > 2.14.1 >
Sebastian
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