netdev - Re: [PATCH net-next 1/7] dma: compile-out DMA sync op calls when not used

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240131165258.GA401365@kernel.org>
Date: Wed, 31 Jan 2024 17:52:58 +0100
From: Simon Horman <horms@...nel.org>
To: Alexander Lobakin <aleksander.lobakin@...el.com>
Cc: "David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Christoph Hellwig <hch@....de>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Robin Murphy <robin.murphy@....com>, Joerg Roedel <joro@...tes.org>,
	Will Deacon <will@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Magnus Karlsson <magnus.karlsson@...el.com>,
	Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
	Alexander Duyck <alexanderduyck@...com>, bpf@...r.kernel.org,
	netdev@...r.kernel.org, iommu@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next 1/7] dma: compile-out DMA sync op calls when not
 used

On Fri, Jan 26, 2024 at 02:54:50PM +0100, Alexander Lobakin wrote:
> Some platforms do have DMA, but DMA there is always direct and coherent.
> Currently, even on such platforms DMA sync operations are compiled and
> called.
> Add a new hidden Kconfig symbol, DMA_NEED_SYNC, and set it only when
> either sync operations are needed or there is DMA ops or swiotlb
> enabled. Set dma_need_sync() and dma_skip_sync() (stub for now)
> depending on this symbol state and don't call sync ops when
> dma_skip_sync() is true.
> The change allows for future optimizations of DMA sync calls depending
> on compile-time or runtime conditions.
> 
> Signed-off-by: Alexander Lobakin <aleksander.lobakin@...el.com>

Hi Alexander,

This seems to cause x86_64 allmodconfig builds to fail:

 ../drivers/media/platform/ti/omap3isp/ispstat.c:82:35: error: ‘dma_sync_single_range_for_device’ undeclared (first use in this function); did you mean ‘dma_sync_sgtable_for_device’?
    82 |                                   dma_sync_single_range_for_device);
       |                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       |                                   dma_sync_sgtable_for_device
 ../drivers/media/platform/ti/omap3isp/ispstat.c:82:35: note: each undeclared identifier is reported only once for each function it appears in
 ../drivers/media/platform/ti/omap3isp/ispstat.c: In function ‘isp_stat_buf_sync_magic_for_cpu’:
 ../drivers/media/platform/ti/omap3isp/ispstat.c:94:35: error: ‘dma_sync_single_range_for_cpu’ undeclared (first use in this function); did you mean ‘dma_sync_sgtable_for_cpu’?
    94 |                                   dma_sync_single_range_for_cpu);
       |                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       |                                   dma_sync_sgtable_for_cpu