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 <[email protected]> Reported-by: Guenter Roeck <[email protected]> --- arch/sparc/mm/iommu.c | 31 ++++++++++--------------------- 1 file changed, 10 insertions(+), 21 deletions(-) diff --git a/arch/sparc/mm/iommu.c b/arch/sparc/mm/iommu.c index 37b5ce7657f6..8fbc08d14836 100644 --- a/arch/sparc/mm/iommu.c +++ b/arch/sparc/mm/iommu.c @@ -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; } -- 2.20.1
