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From: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
To: Anna-Maria Gleixner <anna-maria-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org,
	bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org
Subject: Re: [PATCH] iommu/amd: Remove redundant WARN_ON()
Date: Fri, 20 Jul 2018 14:36:42 +0200	[thread overview]
Message-ID: <20180720123641.GE18541@8bytes.org> (raw)
In-Reply-To: <20180720084545.3284-1-anna-maria-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>

On Fri, Jul 20, 2018 at 10:45:45AM +0200, Anna-Maria Gleixner wrote:
> The WARN_ON() was introduced in commit 272e4f99e966 ("iommu/amd: WARN
> when __[attach|detach]_device are called with irqs enabled") to ensure
> that the domain->lock is taken in proper irqs disabled context. This
> is required, because the domain->lock is taken as well in irq
> context.
> 
> The proper context check by the WARN_ON() is redundant, because it is
> already covered by LOCKDEP. When working with locks and changing
> context, a run with LOCKDEP is required anyway and would detect the
> wrong lock context.
> 
> Furthermore all callers for those functions are within the same file
> and all callers acquire another lock which already disables interrupts.
> 
> Signed-off-by: Anna-Maria Gleixner <anna-maria-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
> ---
>  drivers/iommu/amd_iommu.c | 12 ------------
>  1 file changed, 12 deletions(-)

Applied, thanks.

      parent reply	other threads:[~2018-07-20 12:36 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-20  8:45 [PATCH] iommu/amd: Remove redundant WARN_ON() Anna-Maria Gleixner
     [not found] ` <20180720084545.3284-1-anna-maria-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2018-07-20 12:36   ` Joerg Roedel [this message]

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