From: Christoph Hellwig <hch@lst.de>
To: Nathan Chancellor <nathan@kernel.org>
Cc: "kernel test robot" <lkp@intel.com>,
"Baruch Siach" <baruch@tkos.co.il>,
"Christoph Hellwig" <hch@lst.de>,
"Marek Szyprowski" <m.szyprowski@samsung.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Will Deacon" <will@kernel.org>,
llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
linux-s390@vger.kernel.org, "Ramon Fried" <ramon@neureality.ai>,
"Petr Tesařík" <petr@tesarici.cz>,
"Robin Murphy" <robin.murphy@arm.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
"Elad Nachman" <enachman@marvell.com>,
linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 2/3] dma-mapping: replace zone_dma_bits by zone_dma_limit
Date: Tue, 30 Jul 2024 17:34:50 +0200 [thread overview]
Message-ID: <20240730153450.GA30021@lst.de> (raw)
In-Reply-To: <20240730021208.GA8272@thelio-3990X>
On Mon, Jul 29, 2024 at 07:12:08PM -0700, Nathan Chancellor wrote:
> > | ~~~~~~~~~~~~~~ ^~~~~~~~~~~~~~~~
> > include/linux/dma-mapping.h:77:40: note: expanded from macro 'DMA_BIT_MASK'
> > 77 | #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
> > | ^~~~~
> > 2 warnings generated.
>
> FWIW, this is likely a false positive due to an issue in Clang with the
> control flow graph for global variables:
>
> https://github.com/ClangBuiltLinux/linux/issues/92
>
> DMA_BIT_MASK() has been the biggest offender :/ If there is any way to
> refactor this code to avoid this, that would be great (as that has been
> one of our longest outstanding issues and getting it fixed in the
> compiler does not seem super easy at this point).
I have no idea what you'd want changed here, but I'll happily take
patches.
next prev parent reply other threads:[~2024-07-30 15:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-29 10:51 [PATCH v3 0/3] dma: support DMA zone starting above 4GB Baruch Siach
2024-07-29 10:51 ` [PATCH v3 1/3] dma-mapping: improve DMA zone selection Baruch Siach
2024-07-29 10:51 ` [PATCH v3 2/3] dma-mapping: replace zone_dma_bits by zone_dma_limit Baruch Siach
2024-07-29 20:20 ` kernel test robot
2024-07-30 2:12 ` Nathan Chancellor
2024-07-30 15:34 ` Christoph Hellwig [this message]
2024-08-01 1:24 ` Nathan Chancellor
2024-08-01 13:44 ` Christoph Hellwig
2024-08-01 15:22 ` Nathan Chancellor
2024-07-31 17:26 ` Catalin Marinas
2024-07-29 10:51 ` [PATCH v3 3/3] dma-direct: use RAM start to offset zone_dma_limit Baruch Siach
2024-07-31 17:33 ` Catalin Marinas
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