DMA Engine development
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From: "Peng Fan (OSS)" <peng.fan@oss.nxp.com>
To: Vinod Koul <vkoul@kernel.org>, Frank Li <Frank.Li@kernel.org>,
	 Sascha Hauer <s.hauer@pengutronix.de>,
	 Pengutronix Kernel Team <kernel@pengutronix.de>,
	 Fabio Estevam <festevam@gmail.com>
Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
	 imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	 Peng Fan <peng.fan@nxp.com>
Subject: [PATCH 1/3] dmaengine: Use non-atomic bit ops for cap_mask manipulation
Date: Thu, 03 Sep 2026 22:16:12 +0800	[thread overview]
Message-ID: <20260903-dma-mask-v1-1-211ffd12c236@nxp.com> (raw)
In-Reply-To: <20260903-dma-mask-v1-0-211ffd12c236@nxp.com>

From: Peng Fan <peng.fan@nxp.com>

dma_cap_set() and dma_cap_clear() are called exclusively during driver
probe, before dma_async_device_register() makes the device visible to
the rest of the system. There is no concurrent access to cap_mask at
that point, so switch to the non-atomic __set_bit()/__clear_bit()
equivalents.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 include/linux/dmaengine.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index fe33a20abc614..923d914691d06 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -1551,14 +1551,14 @@ static inline bool async_tx_test_ack(struct dma_async_tx_descriptor *tx)
 static inline void
 __dma_cap_set(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
 {
-	set_bit(tx_type, dstp->bits);
+	__set_bit(tx_type, dstp->bits);
 }
 
 #define dma_cap_clear(tx, mask) __dma_cap_clear((tx), &(mask))
 static inline void
 __dma_cap_clear(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
 {
-	clear_bit(tx_type, dstp->bits);
+	__clear_bit(tx_type, dstp->bits);
 }
 
 #define dma_cap_zero(mask) __dma_cap_zero(&(mask))

-- 
2.34.1


  reply	other threads:[~2026-09-03 14:12 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-03 14:16 [PATCH 0/3] dmaengine: Use non-atomic bit ops where safe Peng Fan (OSS)
2026-09-03 14:16 ` Peng Fan (OSS) [this message]
2026-09-03 14:20   ` [PATCH 1/3] dmaengine: Use non-atomic bit ops for cap_mask manipulation sashiko-bot
2026-09-03 14:16 ` [PATCH 2/3] dmaengine: imx-sdma: Use non-atomic __set_bit() for event_mask setup Peng Fan (OSS)
2026-09-03 14:23   ` sashiko-bot
2026-09-03 14:16 ` [PATCH 3/3] dmaengine: imx-sdma: Use __assign_bit() for ownership configuration Peng Fan (OSS)
2026-09-03 14:22   ` sashiko-bot
2026-09-03 19:29 ` [PATCH 0/3] dmaengine: Use non-atomic bit ops where safe Frank Li
2026-09-04  2:08   ` Peng Fan

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