[PATCH 15/31] sparc32/iommu: handle page-less SG entries

Christoph Hellwig
2015-08-12T07:05:34Z

Pass a PFN to iommu_get_one instad of calculating it locall from a
page structure so that we don't need pages for every address we can
DMA to or from.

Also further restrict the cache flushing as we now have a non-highmem
way of not kernel virtual mapped physical addresses.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/sparc/mm/iommu.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/sparc/mm/iommu.c b/arch/sparc/mm/iommu.c
index 491511d..3ed53d7 100644
--- a/arch/sparc/mm/iommu.c
+++ b/arch/sparc/mm/iommu.c
@@ -174,7 +174,7 @@ static void iommu_flush_iotlb(iopte_t *iopte, unsigned int niopte)
}
}

-static u32 iommu_get_one(struct device *dev, struct page *page, int npages)
+static u32 iommu_get_one(struct device *dev, unsigned long pfn, int npages)
{
struct iommu_struct *iommu = dev->archdata.iommu;
int ioptex;
@@ -183,7 +183,7 @@ static u32 iommu_get_one(struct device *dev, struct page *page, int npages)
int i;

/* page color = pfn of page */
- ioptex = bit_map_string_get(&iommu->usemap, npages, page_to_pfn(page));
+ ioptex = bit_map_string_get(&iommu->usemap, npages, pfn);
if (ioptex < 0)
panic("iommu out");
busa0 = iommu->start + (ioptex << PAGE_SHIFT);
@@ -192,11 +192,11 @@ static u32 iommu_get_one(struct device *dev, struct page *page, int npages)
busa = busa0;
iopte = iopte0;
for (i = 0; i < npages; i++) {
- iopte_val(*iopte) = MKIOPTE(page_to_pfn(page), IOPERM);
+ iopte_val(*iopte) = MKIOPTE(pfn, IOPERM);
iommu_invalidate_page(iommu->regs, busa);
busa += PAGE_SIZE;
iopte++;
- page++;
+ pfn++;
}

iommu_flush_iotlb(iopte0, npages);
@@ -214,7 +214,7 @@ static u32 iommu_get_scsi_one(struct device *dev, char *vaddr, unsigned int len)
off = (unsigned long)vaddr & ~PAGE_MASK;
npages = (off + len + PAGE_SIZE-1) >> PAGE_SHIFT;
page = virt_to_page((unsigned long)vaddr & PAGE_MASK);
- busa = iommu_get_one(dev, page, npages);
+ busa = iommu_get_one(dev, page_to_pfn(page), npages);
return busa + off;
}

@@ -243,7 +243,7 @@ static void iommu_get_scsi_sgl_gflush(struct device *dev, struct scatterlist *sg
while (sz != 0) {
--sz;
n = (sg->length + sg->offset + PAGE_SIZE-1) >> PAGE_SHIFT;
- sg->dma_address = iommu_get_one(dev, sg_page(sg), n) + sg->offset;
+ sg->dma_address = iommu_get_one(dev, sg_pfn(sg), n) + sg->offset;
sg->dma_length = sg->length;
sg = sg_next(sg);
}
@@ -264,7 +264,8 @@ static void iommu_get_scsi_sgl_pflush(struct device *dev, struct scatterlist *sg
* XXX Is this a good assumption?
* XXX What if someone else unmaps it here and races us?
*/
- if ((page = (unsigned long) page_address(sg_page(sg))) != 0) {
+ if (sg_has_page(sg) &&
+ (page = (unsigned long) page_address(sg_page(sg))) != 0) {
for (i = 0; i < n; i++) {
if (page != oldpage) { /* Already flushed? */
flush_page_for_dma(page);
@@ -274,7 +275,7 @@ static void iommu_get_scsi_sgl_pflush(struct device *dev, struct scatterlist *sg
}
}

- sg->dma_address = iommu_get_one(dev, sg_page(sg), n) + sg->offset;
+ sg->dma_address = iommu_get_one(dev, sg_pfn(sg), n) + sg->offset;
sg->dma_length = sg->length;
sg = sg_next(sg);
}
--
1.9.1