[PATCH 6/8] swiotlb: lift the double initialization protection from xen-swiotlb
From: Christoph Hellwig <hch@lst.de>
Date: 2021-02-07 16:19:34
Also in:
linux-iommu, xen-devel
Subsystem:
dma mapping helpers, the rest, xen hypervisor interface, xen swiotlb subsystem · Maintainers:
Marek Szyprowski, Linus Torvalds, Juergen Gross, Stefano Stabellini
Lift the double initialization protection from xen-swiotlb to the core code to avoid exposing too many swiotlb internals. Also upgrade the check to a warning as it should not happen. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/xen/swiotlb-xen.c | 7 ------- kernel/dma/swiotlb.c | 8 ++++++++ 2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 6e0f2c5ecd1a2f..e6c8556e879ee6 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c@@ -172,12 +172,6 @@ int __ref xen_swiotlb_init(int verbose, bool early) bytes = nslabs << IO_TLB_SHIFT; order = get_order(bytes); - /* - * IO TLB memory already allocated. Just use it. - */ - if (io_tlb_start != 0) - goto end; - /* * Get IO TLB memory from any location. */
@@ -232,7 +226,6 @@ int __ref xen_swiotlb_init(int verbose, bool early) } else rc = swiotlb_late_init_with_tbl(start, nslabs); -end: if (!rc) swiotlb_set_max_segment(PAGE_SIZE);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index adcc3c87e10078..a3737961ae5769 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c@@ -224,6 +224,10 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) unsigned long i, bytes; size_t alloc_size; + /* protect against double initialization */ + if (WARN_ON_ONCE(io_tlb_start)) + return -ENOMEM; + bytes = nslabs << IO_TLB_SHIFT; io_tlb_nslabs = nslabs;
@@ -355,6 +359,10 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) { unsigned long i, bytes; + /* protect against double initialization */ + if (WARN_ON_ONCE(io_tlb_start)) + return -ENOMEM; + bytes = nslabs << IO_TLB_SHIFT; io_tlb_nslabs = nslabs;
--
2.29.2