From 53b29c336830db48ad3dc737f88b8c065b1f0851 Mon Sep 17 00:00:00 2001 From: Dongli Zhang Date: Fri, 12 Apr 2019 19:38:26 +0800 Subject: [PATCH] swiotlb: save io_tlb_used to local variable before leaving critical section MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Dongli Zhang Signed-off-by: Konrad Rzeszutek Wilk --- 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 82c767374c70..38d57218809c 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -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;