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From: Heiner Kallweit <hkallweit1@gmail.com>
To: Christoph Hellwig <hch@lst.de>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>
Cc: "open list:AMD IOMMU \(AMD-VI\)" <iommu@lists.linux-foundation.org>
Subject: [PATCH] dma-mapping: add unlikely hint to error path in dma_mapping_error
Date: Fri, 26 Mar 2021 22:03:05 +0100	[thread overview]
Message-ID: <78757abc-ef8f-9a29-9020-967370eec365@gmail.com> (raw)

Zillions of drivers use the unlikely() hint when checking the result of
dma_mapping_error(). This is an inline function anyway, so we can move
the hint into the function and remove it from drivers over time.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
This is a resend of a patch from Dec 2020 when I tried to do it
tree-wide. Now start with the actual change, drivers can be changed
afterwards, maybe per subsystem.
---
 include/linux/dma-mapping.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index e9d19b974..183e7103a 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -95,7 +95,7 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 {
 	debug_dma_mapping_error(dev, dma_addr);
 
-	if (dma_addr == DMA_MAPPING_ERROR)
+	if (unlikely(dma_addr == DMA_MAPPING_ERROR))
 		return -ENOMEM;
 	return 0;
 }
-- 
2.31.0

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             reply	other threads:[~2021-03-26 21:03 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26 21:03 Heiner Kallweit [this message]
2021-03-30 10:21 ` [PATCH] dma-mapping: add unlikely hint to error path in dma_mapping_error Robin Murphy
2021-03-30 10:54   ` Heiner Kallweit
2021-03-30 10:59 ` Heiner Kallweit
2021-04-02 14:41 ` Christoph Hellwig

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