summaryrefslogtreecommitdiff
path: root/kernel/dma
diff options
context:
space:
mode:
authorTianyu Lan <Tianyu.Lan@microsoft.com>2022-05-10 10:21:09 -0400
committerChristoph Hellwig <hch@lst.de>2022-05-17 11:21:52 +0200
commit82806744fd7dde603b64c151eeddaa4ee62193fd (patch)
tree6c786e6c1cc169caa1ada407b9b2c5d03a443cba /kernel/dma
parent1b8e5d1a53696d92374acce2b19a649427f1ec1e (diff)
swiotlb: max mapping size takes min align mask into account
swiotlb_find_slots() skips slots according to io tlb aligned mask calculated from min aligned mask and original physical address offset. This affects max mapping size. The mapping size can't achieve the IO_TLB_SEGSIZE * IO_TLB_SIZE when original offset is non-zero. This will cause system boot up failure in Hyper-V Isolation VM where swiotlb force is enabled. Scsi layer use return value of dma_max_mapping_size() to set max segment size and it finally calls swiotlb_max_mapping_size(). Hyper-V storage driver sets min align mask to 4k - 1. Scsi layer may pass 256k length of request buffer with 0~4k offset and Hyper-V storage driver can't get swiotlb bounce buffer via DMA API. Swiotlb_find_slots() can't find 256k length bounce buffer with offset. Make swiotlb_max_mapping _size() take min align mask into account. Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma')
-rw-r--r--kernel/dma/swiotlb.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index d6e62a6a42ce..dfa1de89dc94 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -736,7 +736,18 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
size_t swiotlb_max_mapping_size(struct device *dev)
{
- return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE;
+ int min_align_mask = dma_get_min_align_mask(dev);
+ int min_align = 0;
+
+ /*
+ * swiotlb_find_slots() skips slots according to
+ * min align mask. This affects max mapping size.
+ * Take it into acount here.
+ */
+ if (min_align_mask)
+ min_align = roundup(min_align_mask, IO_TLB_SIZE);
+
+ return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE - min_align;
}
bool is_swiotlb_active(struct device *dev)