From 8088546832aa2c0d8f99dd56edf6384f8a9b63b3 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 12 Apr 2018 10:38:08 +0200 Subject: swiotlb: do not panic on mapping failures All properly written drivers now have error handling in the dma_map_single / dma_map_page callers. As swiotlb_tbl_map_single already prints a useful warning when running out of swiotlb pool space we can also remove swiotlb_full entirely as it serves no purpose now. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy --- kernel/dma/swiotlb.c | 33 +-------------------------------- 1 file changed, 1 insertion(+), 32 deletions(-) (limited to 'kernel/dma/swiotlb.c') diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 26d3af52956f..69bf305ee5f8 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -761,34 +761,6 @@ static bool swiotlb_free_buffer(struct device *dev, size_t size, return true; } -static void -swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir, - int do_panic) -{ - if (swiotlb_force == SWIOTLB_NO_FORCE) - return; - - /* - * Ran out of IOMMU space for this operation. This is very bad. - * Unfortunately the drivers cannot handle this operation properly. - * unless they check for dma_mapping_error (most don't) - * When the mapping is small enough return a static buffer to limit - * the damage, or panic when the transfer is too big. - */ - dev_err_ratelimited(dev, "DMA: Out of SW-IOMMU space for %zu bytes\n", - size); - - if (size <= io_tlb_overflow || !do_panic) - return; - - if (dir == DMA_BIDIRECTIONAL) - panic("DMA: Random memory could be DMA accessed\n"); - if (dir == DMA_FROM_DEVICE) - panic("DMA: Random memory could be DMA written\n"); - if (dir == DMA_TO_DEVICE) - panic("DMA: Random memory could be DMA read\n"); -} - /* * Map a single buffer of the indicated size for DMA in streaming mode. The * physical address to use is returned. @@ -817,10 +789,8 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, /* Oh well, have to allocate and map a bounce buffer. */ map = map_single(dev, phys, size, dir, attrs); - if (map == SWIOTLB_MAP_ERROR) { - swiotlb_full(dev, size, dir, 1); + if (map == SWIOTLB_MAP_ERROR) return __phys_to_dma(dev, io_tlb_overflow_buffer); - } dev_addr = __phys_to_dma(dev, map); @@ -948,7 +918,6 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems, if (map == SWIOTLB_MAP_ERROR) { /* Don't panic here, we expect map_sg users to do proper error handling. */ - swiotlb_full(hwdev, sg->length, dir, 0); attrs |= DMA_ATTR_SKIP_CPU_SYNC; swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, attrs); -- cgit