From: Steven Rostedt <rost...@goodmis.org> I'm working on code that will warn when a tracepoint is defined but not used. As the TRACE_EVENT() logic still creates all the code regardless if something calls the trace_<event>() function. It wastes around 5K per trace event (less for tracepoints).
But it seems that the code in drivers/iommu/dma-iommu.c does the opposite. It calls the trace_swiotlb_bounced() tracepoint without it being defined. The tracepoint is defined in kernel/dma/swiotlb.c when CONFIG_SWIOTLB is defined, but this code exists when that config is not defined. This now fails with my work because I have all the callers reference the tracepoint that they will call. Thanks to the kernel test robot, it found this: https://lore.kernel.org/all/202506091015.7zd87ki7-...@intel.com/ Instead of calling trace_swiotlb_bounced() from drivers/iommu/dma-iommu.c where it is useless when CONFIG_SWIOTLB is not defined, move the tracepoint into swiotlb_tbl_map_single(). This also makes it consistent with which memory is being traced (physical as supposed to dma address). Fixes: ed18a46262be4 ("iommu/dma: Factor out a iommu_dma_map_swiotlb helper") Closes: https://lore.kernel.org/all/20250610202457.5a599...@gandalf.local.home/ Suggested-by: Christoph Hellwig <h...@infradead.org> Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org> --- drivers/iommu/dma-iommu.c | 2 -- kernel/dma/swiotlb.c | 2 ++ 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index ea2ef53bd4fe..1935b360cc94 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1153,8 +1153,6 @@ static phys_addr_t iommu_dma_map_swiotlb(struct device *dev, phys_addr_t phys, return (phys_addr_t)DMA_MAPPING_ERROR; } - trace_swiotlb_bounced(dev, phys, size); - phys = swiotlb_tbl_map_single(dev, phys, size, iova_mask(iovad), dir, attrs); diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index abcf3fa63a56..c112f1d98861 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -1379,6 +1379,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr, phys_addr_t tlb_addr; unsigned short pad_slots; + trace_swiotlb_bounced(dev, orig_addr, mapping_size); + if (!mem || !mem->nslabs) { dev_warn_ratelimited(dev, "Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer"); -- 2.47.2
