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sparc/iommu: use __sbus_iommu_map_page to implement the map_sg path 

This means we handle > PAGE_SIZE offsets fine, and grow the size check
so far only performed in the map_page path.  We lose the optimization
to not double flush a page if it apears in multiple consecutive SG list
entries.  But at least for block I/O those don't happen anymore since
we properly merge in higher layers anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Christoph Hellwig 2019-04-16 20:23:46 +02:00 committed by David S. Miller
parent 7e996890b8
commit edb1f07203
1 changed files with 10 additions and 21 deletions
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31
arch/sparc/mm/iommu.c
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@ -217,6 +217,11 @@ static dma_addr_t __sbus_iommu_map_page(struct device *dev, struct page *page,
if (!len || len > 256 * 1024)
return DMA_MAPPING_ERROR;
/*
* We expect unmapped highmem pages to be not in the cache.
* XXX Is this a good assumption?
* XXX What if someone else unmaps it here and races us?
*/
if (per_page_flush && !PageHighMem(page)) {
unsigned long vaddr, p;
@ -247,30 +252,14 @@ static int __sbus_iommu_map_sg(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir, unsigned long attrs,
bool per_page_flush)
{
unsigned long page, oldpage = 0;
struct scatterlist *sg;
int i, j, n;
int j;
for_each_sg(sgl, sg, nents, j) {
n = (sg->length + sg->offset + PAGE_SIZE-1) >> PAGE_SHIFT;
/*
* We expect unmapped highmem pages to be not in the cache.
* XXX Is this a good assumption?
* XXX What if someone else unmaps it here and races us?
*/
if (per_page_flush && !PageHighMem(sg_page(sg))) {
page = (unsigned long)page_address(sg_page(sg));
for (i = 0; i < n; i++) {
if (page != oldpage) { /* Already flushed? */
flush_page_for_dma(page);
oldpage = page;
}
page += PAGE_SIZE;
}
}
sg->dma_address = iommu_get_one(dev, sg_phys(sg), n) + sg->offset;
sg->dma_address =__sbus_iommu_map_page(dev, sg_page(sg),
sg->offset, sg->length, per_page_flush);
if (sg->dma_address == DMA_MAPPING_ERROR)
return 0;
sg->dma_length = sg->length;
}