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From:   John Stultz <john.stultz@linaro.org>
Date:   Mon, 29 Nov 2021 10:05:00 -0800
Message-ID: <CALAqxLVF1BPznzwjem2BcsDDoo5gMoBqjKEceZDLJan4zCtk3w@mail.gmail.com>
Subject: Re: [PATCH v4] dma-buf: system_heap: Use 'for_each_sgtable_sg' in
 pages free flow
To:     guangming.cao@mediatek.com
Cc:     greg@kroah.com, Brian.Starkey@arm.com,
        benjamin.gaignard@linaro.org, christian.koenig@amd.com,
        dri-devel@lists.freedesktop.org, labbott@redhat.com,
        linaro-mm-sig@lists.linaro.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, linux-mediatek@lists.infradead.org,
        lmark@codeaurora.org, matthias.bgg@gmail.com, robin.murphy@arm.com,
        stable@vger.kernel.org, sumit.semwal@linaro.org,
        wsd_upstream@mediatek.com, kuan-ying.lee@mediatek.com
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On Thu, Nov 25, 2021 at 11:48 PM <guangming.cao@mediatek.com> wrote:
>
> From: Guangming <Guangming.Cao@mediatek.com>
>
> For previous version, it uses 'sg_table.nent's to traverse sg_table in pages
> free flow.
> However, 'sg_table.nents' is reassigned in 'dma_map_sg', it means the number of
> created entries in the DMA adderess space.
> So, use 'sg_table.nents' in pages free flow will case some pages can't be freed.
>
> Here we should use sg_table.orig_nents to free pages memory, but use the
> sgtable helper 'for each_sgtable_sg'(, instead of the previous rather common
> helper 'for_each_sg' which maybe cause memory leak) is much better.
>
> Fixes: d963ab0f15fb0 ("dma-buf: system_heap: Allocate higher order pages if available")
> Signed-off-by: Guangming <Guangming.Cao@mediatek.com>
> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> Cc: <stable@vger.kernel.org> # 5.11.*

Thanks so much for catching this and sending in all the revisions!

Reviewed-by: John Stultz <john.stultz@linaro.org>