From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH] iommu/amd: Use raw_cpu_ptr() instead of get_cpu_ptr() for ->flush_queue Date: Tue, 19 Sep 2017 11:41:19 +0200 Message-ID: <20170919094119.bibxslqyeefbx7gf@8bytes.org> References: <20170906103459.oi2nn7jondjqdo5m@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20170906103459.oi2nn7jondjqdo5m-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Sebastian Andrzej Siewior Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, vinadhy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: iommu@lists.linux-foundation.org Hi Sebastian, On Wed, Sep 06, 2017 at 12:34:59PM +0200, Sebastian Andrzej Siewior wrote: > get_cpu_ptr() disables preemption and returns the ->flush_queue 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 in general > but on RT it does because the sleeping lock can't be accessed with > disabled preemption. 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? Regards, Joerg