Merge branch 'stable/for-linus-5.0' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb

Pull swiotlb fix from Konrad Rzeszutek Wilk:
 "A tiny fix for v5.0-rc2:

  This fixes an issue with GPU cards not working anymore with the DMA
  mapping work Christopher did - as the SWIOTLB is initialized first and
  then free'd (as IOMMU is available) but we forgot to clear our start
  and end entries which are used and BOOM"

* 'stable/for-linus-5.0' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
  swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit

kernel/dma/swiotlb.c

@@ -378,6 +378,8 @@ void __init swiotlb_exit(void)
 		memblock_free_late(io_tlb_start,
 				   PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
 	}
+	io_tlb_start = 0;
+	io_tlb_end = 0;
 	io_tlb_nslabs = 0;
 	max_segment = 0;
 }