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References: <20210719123054.6844-1-will@kernel.org> <20210719123054.6844-5-will@kernel.org>
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From:   Claire Chang <tientzu@chromium.org>
Date:   Tue, 20 Jul 2021 11:36:07 +0800
Message-ID: <CALiNf2-xKNyucan678dvzc6WwEEn6D0YFJ-DssdTDzqe9CGcgQ@mail.gmail.com>
Subject: Re: [PATCH 4/5] swiotlb: Emit diagnostic in swiotlb_exit()
To:     Will Deacon <will@kernel.org>
Cc:     "list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>, Joerg
        Roedel <joro@8bytes.org>," <iommu@lists.linux-foundation.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Christoph Hellwig <hch@lst.de>,
        Robin Murphy <robin.murphy@arm.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Nathan Chancellor <nathan@kernel.org>
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On Mon, Jul 19, 2021 at 8:31 PM Will Deacon <will@kernel.org> wrote:
>
> A recent debugging session would have been made a little bit easier if
> we had noticed sooner that swiotlb_exit() was being called during boot.
>
> Add a simple diagnostic message to swiotlb_exit() to complement the one
> from swiotlb_print_info() during initialisation.
>
> Cc: Claire Chang <tientzu@chromium.org>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Robin Murphy <robin.murphy@arm.com>
> Link: https://lore.kernel.org/r/20210705190352.GA19461@willie-the-truck
> Suggested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Tested-by: Nathan Chancellor <nathan@kernel.org>

Tested-by: Claire Chang <tientzu@chromium.org>

> Signed-off-by: Will Deacon <will@kernel.org>
> ---
>  kernel/dma/swiotlb.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 7948f274f9bb..b3c793ed9e64 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -334,6 +334,7 @@ void __init swiotlb_exit(void)
>         if (!mem->nslabs)
>                 return;
>
> +       pr_info("tearing down default memory pool\n");
>         size = array_size(sizeof(*mem->slots), mem->nslabs);
>         if (mem->late_alloc)
>                 free_pages((unsigned long)mem->slots, get_order(size));
> --
> 2.32.0.402.g57bb445576-goog
>