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-rw-r--r--lib/swiotlb.c30
1 files changed, 16 insertions, 14 deletions
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 4bb5a11e18a..025922807e6 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -310,7 +310,9 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
start_dma_addr = virt_to_bus(io_tlb_start) & mask;
offset_slots = ALIGN(start_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
- max_slots = ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ max_slots = mask + 1
+ ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
+ : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
/*
* For mappings greater than a page, we limit the stride (and
@@ -333,16 +335,18 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
index = ALIGN(io_tlb_index, stride);
if (index >= io_tlb_nslabs)
index = 0;
-
- while (is_span_boundary(index, nslots, offset_slots,
- max_slots)) {
- index += stride;
- if (index >= io_tlb_nslabs)
- index = 0;
- }
wrap = index;
do {
+ while (is_span_boundary(index, nslots, offset_slots,
+ max_slots)) {
+ index += stride;
+ if (index >= io_tlb_nslabs)
+ index = 0;
+ if (index == wrap)
+ goto not_found;
+ }
+
/*
* If we find a slot that indicates we have 'nslots'
* number of contiguous buffers, we allocate the
@@ -367,14 +371,12 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
goto found;
}
- do {
- index += stride;
- if (index >= io_tlb_nslabs)
- index = 0;
- } while (is_span_boundary(index, nslots, offset_slots,
- max_slots));
+ index += stride;
+ if (index >= io_tlb_nslabs)
+ index = 0;
} while (index != wrap);
+ not_found:
spin_unlock_irqrestore(&io_tlb_lock, flags);
return NULL;
}