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Commit 53b29c33 authored by Dongli Zhang's avatar Dongli Zhang Committed by Konrad Rzeszutek Wilk
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swiotlb: save io_tlb_used to local variable before leaving critical section 



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: 83ca2594 ("swiotlb: dump used and total slots when swiotlb buffer is full")
Suggested-by: default avatarHåkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: default avatarDongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 83ca2594

kernel/dma/swiotlb.c

+5 −2
Original line number Diff line number Diff line
@@ -445,6 +445,7 @@ 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");
@@ -531,10 +532,12 @@ 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;