From 94e2cc4dba39efbb63e84cd4f7243627c16ceac5 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 21 Sep 2017 17:21:40 +0200 Subject: [PATCH] iommu/iova: Use raw_cpu_ptr() instead of get_cpu_ptr() for ->fq 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. Cc: Joerg Roedel Cc: iommu@lists.linux-foundation.org Reported-by: vinadhy@gmail.com Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Alex Williamson --- 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 84bda3a4dafc..466aaa8ba841 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -542,7 +542,7 @@ 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; @@ -572,8 +572,6 @@ 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);