From: Christoph Hellwig <hch@lst.de>
To: iommu@lists.linux-foundation.org
Cc: Joerg Roedel <joro@8bytes.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] dma-direct: only limit the mapping size if swiotlb could be used
Date: Wed, 17 Jul 2019 08:26:15 +0200 [thread overview]
Message-ID: <20190717062615.10569-3-hch@lst.de> (raw)
In-Reply-To: <20190717062615.10569-1-hch@lst.de>
Don't just check for a swiotlb buffer, but also if buffering might
be required for this particular device.
Fixes: 133d624b1cee ("dma: Introduce dma_max_mapping_size()")
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
kernel/dma/direct.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index d7cec866d16b..e269b6f9b444 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -399,11 +399,9 @@ int dma_direct_supported(struct device *dev, u64 mask)
size_t dma_direct_max_mapping_size(struct device *dev)
{
- size_t size = SIZE_MAX;
-
/* If SWIOTLB is active, use its maximum mapping size */
- if (is_swiotlb_active())
- size = swiotlb_max_mapping_size(dev);
-
- return size;
+ if (is_swiotlb_active() &&
+ (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE))
+ return swiotlb_max_mapping_size(dev);
+ return SIZE_MAX;
}
--
2.20.1
prev parent reply other threads:[~2019-07-17 6:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-17 6:26 fix nvme performance regression due to dma_max_mapping_size() Christoph Hellwig
2019-07-17 6:26 ` [PATCH 1/2] dma-mapping: add a dma_addressing_limited helper Christoph Hellwig
2019-07-17 6:26 ` Christoph Hellwig [this message]
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