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From: Joerg Roedel <joro@8bytes.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: iommu@lists.linux-foundation.org, vinadhy@gmail.com,
	linux-kernel@vger.kernel.org
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	[thread overview]
Message-ID: <20170919094119.bibxslqyeefbx7gf@8bytes.org> (raw)
In-Reply-To: <20170906103459.oi2nn7jondjqdo5m@linutronix.de>

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

  reply	other threads:[~2017-09-19  9:41 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-06 10:34 Sebastian Andrzej Siewior
2017-09-19  9:41 ` Joerg Roedel [this message]
2017-09-21 15:21   ` [PATCH v2] iommu/iova: Use raw_cpu_ptr() instead of get_cpu_ptr() for ->fq Sebastian Andrzej Siewior
2017-11-02 17:33     ` Sebastian Andrzej Siewior
2017-11-06 15:43       ` Alex Williamson
2017-11-06 16:45         ` Robin Murphy
2017-11-06 20:07           ` Alex Williamson
     [not found] ` <CABp9dQUcXTAX9ggX+TAMHE2oH0SF8bcu47E=UYG9fgJdKBXEVg@mail.gmail.com>
2017-09-21 15:10   ` [PATCH] iommu/amd: Use raw_cpu_ptr() instead of get_cpu_ptr() for ->flush_queue Sebastian Andrzej Siewior

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