DMA Engine development
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From: Maoyi Xie <maoyixie.tju@gmail.com>
To: Vinod Koul <vkoul@kernel.org>
Cc: Frank Li <Frank.Li@kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	dmaengine@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 0/2] dmaengine: fix dead empty checks in mpc512x and rz-dmac
Date: Thu, 21 May 2026 22:47:53 +0800	[thread overview]
Message-ID: <20260521144755.3476353-1-maoyixie.tju@gmail.com> (raw)

Two dmaengine drivers use list_first_entry() and then test the
returned pointer against NULL. list_first_entry() never returns
NULL, so the NULL check is dead code. The author intent at both
sites was clear from the existing recovery path. Switch to
list_first_entry_or_null() so the existing NULL path runs.

The two sites were raised in an inquiry on 2026-05-20. Frank Li
confirmed and asked for a patch.

Maoyi Xie (2):
  dmaengine: mpc512x: fix dead empty check in mpc_dma_prep_slave_sg()
  dmaengine: rz-dmac: fix dead empty check in rz_dmac_chan_get_residue()

 drivers/dma/mpc512x_dma.c | 4 ++--
 drivers/dma/sh/rz-dmac.c  | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

--
2.34.1

             reply	other threads:[~2026-05-21 14:48 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-21 14:47 Maoyi Xie [this message]
2026-05-21 14:47 ` [PATCH 1/2] dmaengine: mpc512x: fix dead empty check in mpc_dma_prep_slave_sg() Maoyi Xie
2026-05-21 15:42   ` sashiko-bot
2026-05-21 16:30   ` Frank Li
2026-05-22 15:02   ` [PATCH v2] " Maoyi Xie
2026-05-22 15:23     ` sashiko-bot
2026-05-21 14:47 ` [PATCH 2/2] dmaengine: rz-dmac: fix dead empty check in rz_dmac_chan_get_residue() Maoyi Xie
2026-05-21 16:05   ` sashiko-bot
2026-05-22  8:16   ` Geert Uytterhoeven
2026-05-22  8:37     ` Maoyi Xie

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