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From: Karl Mehltretter <kmehltretter@gmail.com>
To: Russell King <linux@armlinux.org.uk>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>,
	 Robin Murphy <robin.murphy@arm.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	 Will Deacon <will@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Christoph Hellwig <hch@lst.de>,
	 Linus Walleij <linusw@kernel.org>,
	Ard Biesheuvel <ardb@kernel.org>,
	 linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 2/2] ARM: dma-mapping: flush FROM_DEVICE buffers on legacy backends
Date: Sat, 12 Sep 2026 08:55:08 +0200	[thread overview]
Message-ID: <aqT2kBGIQJLWEqkf@gmail.com> (raw)
In-Reply-To: <20260910063620.17768-3-kmehltretter@gmail.com>

On Thu, Sep 10, 2026 at 08:36:20AM +0100, Karl Mehltretter wrote:
> The legacy write-back cache backends invalidate DMA_FROM_DEVICE buffers
> when ownership passes to the device. A plain invalidate can discard dirty
> CPU cache lines. If the device writes only part of the buffer, untouched
> bytes can expose memory contents older than those present at the handoff.

Sashiko flagged unused *_dma_inv_range helpers in its dashboard review
of this patch [1].

I can remove the unused invalidate helpers in a separate cleanup patch in
v2.

[1] https://sashiko.dev/#/patchset/20260910063620.17768-1-kmehltretter@gmail.com

Thanks,
Karl

  reply	other threads:[~2026-09-12  6:55 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-10  6:36 [PATCH 0/2] ARM: preserve DMA_FROM_DEVICE buffer contents Karl Mehltretter
2026-09-10  6:36 ` [PATCH 1/2] ARM: dma-mapping: " Karl Mehltretter
2026-09-10  6:36 ` [PATCH 2/2] ARM: dma-mapping: flush FROM_DEVICE buffers on legacy backends Karl Mehltretter
2026-09-12  6:55   ` Karl Mehltretter [this message]
2026-09-10  6:48 ` [PATCH 0/2] ARM: preserve DMA_FROM_DEVICE buffer contents Karl Mehltretter
2026-09-10  9:14 ` Arnd Bergmann
2026-09-10 10:55   ` Will Deacon
2026-09-10 13:15     ` Arnd Bergmann
2026-09-12  6:59   ` Karl Mehltretter

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