From: Christoph Hellwig <hch@lst.de>
Date: Mon, 14 Jan 2019 20:14:08 +0000 (+0100)
Subject: swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit
X-Git-Tag: v5.0-rc3~33^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=227a76b64718888c1687cc237463aa000ae6fb2b;p=thirdparty%2Flinux.git

swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit

Otherwise is_swiotlb_buffer will return false positives when
we first initialize a swiotlb buffer, but then free it because
we have an IOMMU available.

Fixes: 55897af63091 ("dma-direct: merge swiotlb_dma_ops into the dma_direct code")
Reported-by: Sibren Vasse <sibren@sibrenvasse.nl>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Sibren Vasse <sibren@sibrenvasse.nl>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index d6361776dc5ce..1fb6fd68b9c7e 100644
--- a/kernel/dma/swiotlb.c
+++ b/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;
 }