swiotlb: manipulate orig_addr when tlb_addr has offset
commit 5f89468e upstream. in case of driver wants to sync part of ranges with offset, swiotlb_tbl_sync_single() copies from orig_addr base to tlb_addr with offset and ends up with data mismatch. It was removed from "swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single", but said logic has to be added back in. From Linus's email: "That commit which the removed the offset calculation entirely, because the old (unsigned long)tlb_addr & (IO_TLB_SIZE - 1) was wrong, but instead of removing it, I think it should have just fixed it to be (tlb_addr - mem->start) & (IO_TLB_SIZE - 1); instead. That way the slot offset always matches the slot index calculation." (Unfortunatly that broke NVMe). The use-case that drivers are hitting is as follow: 1. Get dma_addr_t from dma_map_single() dma_addr_t tlb_addr = dma_map_single(dev, vaddr, vsize, DMA_TO_DEVICE); |<---------------vsize------------->| +-----------------------------------+ | | original buffer +-----------------------------------+ vaddr swiotlb_align_offset |<----->|<---------------vsize------------->| +-------+-----------------------------------+ | | | swiotlb buffer +-------+-----------------------------------+ tlb_addr 2. Do something 3. Sync dma_addr_t through dma_sync_single_for_device(..) dma_sync_single_for_device(dev, tlb_addr + offset, size, DMA_TO_DEVICE); Error case. Copy data to original buffer but it is from base addr (instead of base addr + offset) in original buffer: swiotlb_align_offset |<----->|<- offset ->|<- size ->| +-------+-----------------------------------+ | | |##########| | swiotlb buffer +-------+-----------------------------------+ tlb_addr |<- size ->| +-----------------------------------+ |##########| | original buffer +-----------------------------------+ vaddr The fix is to copy the data to the original buffer and take into account the offset, like so: swiotlb_align_offset |<----->|<- offset ->|<- size ->| +-------+-----------------------------------+ | | |##########| | swiotlb buffer +-------+-----------------------------------+ tlb_addr |<- offset ->|<- size ->| +-----------------------------------+ | |##########| | original buffer +-----------------------------------+ vaddr [One fix which was Linus's that made more sense to as it created a symmetry would break NVMe. The reason for that is the: unsigned int offset = (tlb_addr - mem->start) & (IO_TLB_SIZE - 1); would come up with the proper offset, but it would lose the alignment (which this patch contains).] Fixes: 16fc3cef ("swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single") Signed-off-by:Bumyong Lee <bumyong.lee@samsung.com> Signed-off-by:
Chanho Park <chanho61.park@samsung.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Reported-by:
Dominique MARTINET <dominique.martinet@atmark-techno.com> Reported-by:
Horia Geantă <horia.geanta@nxp.com> Tested-by:
Horia Geantă <horia.geanta@nxp.com> CC: stable@vger.kernel.org Signed-off-by:
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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