From: Joerg Roedel <joro@8bytes.org>
To: "Michael S . Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
virtualization@lists.linux-foundation.org,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
iommu@lists.linux-foundation.org, jfehlig@suse.com,
jon.grimm@amd.com, brijesh.singh@amd.com, joro@8bytes.org,
jroedel@suse.de
Subject: [PATCH 2/3] dma: Introduce dma_max_mapping_size()
Date: Tue, 15 Jan 2019 14:22:56 +0100 [thread overview]
Message-ID: <20190115132257.6426-3-joro@8bytes.org> (raw)
In-Reply-To: <20190115132257.6426-1-joro@8bytes.org>
From: Joerg Roedel <jroedel@suse.de>
The function returns the maximum size that can be mapped
using DMA-API functions. The patch also adds the
implementation for direct DMA and a new dma_map_ops pointer
so that other implementations can expose their limit.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
include/linux/dma-mapping.h | 16 ++++++++++++++++
kernel/dma/direct.c | 10 ++++++++++
2 files changed, 26 insertions(+)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..a3ca8a71a704 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -130,6 +130,7 @@ struct dma_map_ops {
enum dma_data_direction direction);
int (*dma_supported)(struct device *dev, u64 mask);
u64 (*get_required_mask)(struct device *dev);
+ size_t (*max_mapping_size)(struct device *dev);
};
#define DMA_MAPPING_ERROR (~(dma_addr_t)0)
@@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
}
#endif
+size_t dma_direct_max_mapping_size(struct device *dev);
+
#ifdef CONFIG_HAS_DMA
#include <asm/dma-mapping.h>
@@ -440,6 +443,19 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
return 0;
}
+static inline size_t dma_max_mapping_size(struct device *dev)
+{
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+ size_t size = SIZE_MAX;
+
+ if (dma_is_direct(ops))
+ size = dma_direct_max_mapping_size(dev);
+ else if (ops && ops->max_mapping_size)
+ size = ops->max_mapping_size(dev);
+
+ return size;
+}
+
void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
gfp_t flag, unsigned long attrs);
void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..84917e1003c4 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -380,3 +380,13 @@ int dma_direct_supported(struct device *dev, u64 mask)
*/
return mask >= __phys_to_dma(dev, min_mask);
}
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+ /*
+ * Return the minimum of the direct DMA limit and the SWIOTLB limit.
+ * Since direct DMA has no limit, it is fine to just return the SWIOTLB
+ * limit.
+ */
+ return swiotlb_max_mapping_size(dev);
+}
--
2.17.1
next prev parent reply other threads:[~2019-01-15 13:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-15 13:22 [PATCH 0/3 v2] Fix virtio-blk issue with SWIOTLB Joerg Roedel
2019-01-15 13:22 ` [PATCH 1/3] swiotlb: Introduce swiotlb_max_mapping_size() Joerg Roedel
2019-01-15 13:22 ` Joerg Roedel [this message]
2019-01-15 13:37 ` [PATCH 2/3] dma: Introduce dma_max_mapping_size() Christoph Hellwig
2019-01-15 16:23 ` Joerg Roedel
2019-01-15 17:54 ` Christoph Hellwig
2019-01-15 13:22 ` [PATCH 3/3] virtio-blk: Consider dma_max_mapping_size() for maximum segment size Joerg Roedel
2019-01-16 14:05 ` Michael S. Tsirkin
2019-01-16 14:10 ` Joerg Roedel
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