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Date: Sat, 16 Dec 2017 10:51:05 +0000
Message-ID: <867etnvtd2.wl-marc.zyngier@arm.com>
From: Marc Zyngier <marc.zyngier@arm.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-kernel@vger.kernel.org, Matthew Wilcox <mawilcox@microsoft.com>,
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Subject: Re: [PATCH v5 77/78] irqdomain: Convert to XArray
In-Reply-To: <20171215220450.7899-78-willy@infradead.org>
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        <20171215220450.7899-78-willy@infradead.org>
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On Fri, 15 Dec 2017 22:04:49 +0000,
Matthew Wilcox wrote:
> 
> From: Matthew Wilcox <mawilcox@microsoft.com>
> 
> In a non-critical path, irqdomain wants to know how many entries are
> stored in the xarray, so add xa_count().  This is a pretty straightforward
> conversion; mostly just removing now-redundant locking.  The only thing
> of note is just how much simpler irq_domain_fix_revmap() becomes.
> 
> Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
> ---
>  include/linux/irqdomain.h | 10 ++++------
>  include/linux/xarray.h    |  1 +
>  kernel/irq/irqdomain.c    | 39 ++++++++++-----------------------------
>  lib/xarray.c              | 25 +++++++++++++++++++++++++
>  4 files changed, 40 insertions(+), 35 deletions(-)

I certainly welcome the simplification this provides.

As for xa_count(), I'm trying to convince myself that the code under
CONFIG_IRQ_DOMAIN_DEBUG is now completely superseded by
CONFIG_GENERIC_IRQ_DEBUGFS, and that there would be more value in
getting rid of it rather than keeping it on life support.

Until then, the 1:1 replacement is good enough.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>

	M.