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References: <20210629121625.3633999-1-tientzu@chromium.org> <7f544c68-721c-bbcc-3614-cbadce7261a9@arm.com>
In-Reply-To: <7f544c68-721c-bbcc-3614-cbadce7261a9@arm.com>
From:   Claire Chang <tientzu@chromium.org>
Date:   Wed, 30 Jun 2021 12:07:40 +0800
Message-ID: <CALiNf2-WcZo=fyaZqw2axyE-KTmGT0HRqvKiN0NZ5=VKmvA0bQ@mail.gmail.com>
Subject: Re: [PATCH v2] swiotlb: fix implicit debugfs_create_dir declaration
To:     Robin Murphy <robin.murphy@arm.com>
Cc:     Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Christoph Hellwig <hch@lst.de>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Will Deacon <will@kernel.org>,
        Stefano Stabellini <sstabellini@kernel.org>,
        "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>,
        Tomasz Figa <tfiga@chromium.org>,
        Nicolas Boichat <drinkcat@chromium.org>,
        kernel test robot <lkp@intel.com>
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On Tue, Jun 29, 2021 at 8:52 PM Robin Murphy <robin.murphy@arm.com> wrote:
>
> On 2021-06-29 13:16, Claire Chang wrote:
> > Remove the ifdef to fix implicit function declaration for other pools.
> >
> > Fixes: 1d9f94400a7a ("swiotlb: Refactor swiotlb_create_debugfs")
>
> There doesn't appear to be a problem with that commit - AFAICS it's
> 461021875c50 ("swiotlb: Add restricted DMA pool initialization") which
> introduces a reference to debugfs_create_dir() outside the existing
> #ifdef guards.
>
> FWIW (assuming it's the real problem) I'd be inclined to factor out the
> debugfs bits from rmem_swiotlb_device_init() into a separate
> rmem_swiotlb_debugfs_init() (or similar) function which can live
> alongside the others under the #ifdef and be stubbed out in an #else case.

v3 here: https://lore.kernel.org/patchwork/patch/1452807/

>
> Robin.
>
> > Reported-by: kernel test robot <lkp@intel.com>
> > Signed-off-by: Claire Chang <tientzu@chromium.org>
> > ---
> >   kernel/dma/swiotlb.c | 5 -----
> >   1 file changed, 5 deletions(-)
> >
> > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> > index 0ffbaae9fba2..8ae0bef392c3 100644
> > --- a/kernel/dma/swiotlb.c
> > +++ b/kernel/dma/swiotlb.c
> > @@ -36,9 +36,7 @@
> >   #include <linux/scatterlist.h>
> >   #include <linux/mem_encrypt.h>
> >   #include <linux/set_memory.h>
> > -#ifdef CONFIG_DEBUG_FS
> >   #include <linux/debugfs.h>
> > -#endif
> >   #ifdef CONFIG_DMA_RESTRICTED_POOL
> >   #include <linux/io.h>
> >   #include <linux/of.h>
> > @@ -686,7 +684,6 @@ bool is_swiotlb_active(struct device *dev)
> >   }
> >   EXPORT_SYMBOL_GPL(is_swiotlb_active);
> >
> > -#ifdef CONFIG_DEBUG_FS
> >   static struct dentry *debugfs_dir;
> >
> >   static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem)
> > @@ -709,8 +706,6 @@ static int __init swiotlb_create_default_debugfs(void)
> >
> >   late_initcall(swiotlb_create_default_debugfs);
> >
> > -#endif
> > -
> >   #ifdef CONFIG_DMA_RESTRICTED_POOL
> >   struct page *swiotlb_alloc(struct device *dev, size_t size)
> >   {
> >