When swiotlb is full, the kernel would print io_tlb_used. However, the
result might be inaccurate at that time because we have left the critical
section protected by spinlock.
Therefore, we backup the io_tlb_used into local variable before leaving
critical section.
Fixes: 83ca25948940 ("swiotlb: dump used and total slots when swiotlb buffer is
full")
Suggested-by: Håkon Bugge <haakon.bu...@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zh...@oracle.com>
---
kernel/dma/swiotlb.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 857e823..6f7619c 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -452,6 +452,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
unsigned long mask;
unsigned long offset_slots;
unsigned long max_slots;
+ unsigned long tmp_io_tlb_used;
if (no_iotlb_memory)
panic("Can not allocate SWIOTLB buffer earlier and can't now
provide you with the DMA bounce buffer");
@@ -538,10 +539,12 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
} while (index != wrap);
not_found:
+ tmp_io_tlb_used = io_tlb_used;
+
spin_unlock_irqrestore(&io_tlb_lock, flags);
if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
- dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total
%lu, used %lu\n",
- size, io_tlb_nslabs, io_tlb_used);
+ dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total
%lu (slots), used %lu (slots)\n",
+ size, io_tlb_nslabs, tmp_io_tlb_used);
return DMA_MAPPING_ERROR;
found:
io_tlb_used += nslots;
--
2.7.4
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