[PATCH 5.18 0877/1095] swiotlb: fail map correctly with failed io_tlb_default_mem

From: Greg Kroah-Hartman
Date: Mon Aug 15 2022 - 18:42:31 EST


From: Robin Murphy <robin.murphy@xxxxxxx>

[ Upstream commit c51ba246cb172c9e947dc6fb8868a1eaf0b2a913 ]

In the failure case of trying to use a buffer which we'd previously
failed to allocate, the "!mem" condition is no longer sufficient since
io_tlb_default_mem became static and assigned by default. Update the
condition to work as intended per the rest of that conversion.

Fixes: 463e862ac63e ("swiotlb: Convert io_default_tlb_mem to static allocation")
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/dma/swiotlb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 73a41cec9e38..90e5f5c92fdc 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -588,7 +588,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
int index;
phys_addr_t tlb_addr;

- if (!mem)
+ if (!mem || !mem->nslabs)
panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");

if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
--
2.35.1