This patch adds a new capable IOMMU_CAP_MERGING to check whether
the IOVA would be contiguous strictly if a device requires and
the IOMMU driver has the capable.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
drivers/iommu/dma-iommu.c | 26 ++++++++++++++++++++++++--
include/linux/iommu.h | 1 +
2 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 034caae..ecf1a04 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -847,11 +847,16 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
dma_addr_t iova;
size_t iova_len = 0;
unsigned long mask = dma_get_seg_boundary(dev);
- int i;
+ int i, ret;
+ bool iova_contiguous = false;
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
iommu_dma_sync_sg_for_device(dev, sg, nents, dir);
+ if (dma_get_iova_contiguous(dev) &&
+ iommu_capable(dev->bus, IOMMU_CAP_MERGING))
+ iova_contiguous = true;
+
/*
* Work out how much IOVA space we need, and align the segments to
* IOVA granules for the IOMMU driver to handle. With some clever
@@ -867,6 +872,13 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
sg_dma_len(s) = s_length;
s->offset -= s_iova_off;
s_length = iova_align(iovad, s_length + s_iova_off);
+ /*
+ * Check whether the IOVA would be contiguous strictly if
+ * a device requires and the IOMMU driver has the capable.
+ */
+ if (iova_contiguous && i > 0 &&
+ (s_iova_off || s->length != s_length))
+ return 0;
s->length = s_length;
/*
@@ -902,8 +914,18 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
if (iommu_map_sg(domain, iova, sg, nents, prot) < iova_len)
goto out_free_iova;
- return __finalise_sg(dev, sg, nents, iova);
+ ret = __finalise_sg(dev, sg, nents, iova);
+ /*
+ * Check whether the sg entry is single if a device requires and
+ * the IOMMU driver has the capable.
+ */
+ if (iova_contiguous && ret != 1)
+ goto out_unmap_sg;
+
+ return ret;
+out_unmap_sg:
+ iommu_dma_unmap_sg(dev, sg, nents, dir, attrs);
out_free_iova:
iommu_dma_free_iova(cookie, iova, iova_len);
out_restore_sg:
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 91af22a..f971dd3 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -104,6 +104,7 @@ enum iommu_cap {
transactions */
IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */
IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */
+ IOMMU_CAP_MERGING, /* IOMMU supports segments merging */
};
/*
--
2.7.4
