From 58dfd4ac022037c6a562e92fc6d2a778819b2162 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 3 Dec 2018 07:43:05 +0100 Subject: [PATCH] dma-direct: improve addressability error reporting Only report report a DMA addressability report once to avoid spewing the kernel log with repeated message. Also provide a stack trace to make it easy to find the actual caller that caused the problem. Last but not least move the actual check into the fast path and only leave the error reporting in a helper. Signed-off-by: Christoph Hellwig Acked-by: Jesper Dangaard Brouer Tested-by: Jesper Dangaard Brouer Tested-by: Tony Luck --- kernel/dma/direct.c | 36 +++++++++++++++--------------------- 1 file changed, 15 insertions(+), 21 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 308f88a750c8..edb24f94ea1e 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -30,27 +30,16 @@ static inline bool force_dma_unencrypted(void) return sev_active(); } -static bool -check_addr(struct device *dev, dma_addr_t dma_addr, size_t size, - const char *caller) +static void report_addr(struct device *dev, dma_addr_t dma_addr, size_t size) { - if (unlikely(dev && !dma_capable(dev, dma_addr, size))) { - if (!dev->dma_mask) { - dev_err(dev, - "%s: call on device without dma_mask\n", - caller); - return false; - } - - if (*dev->dma_mask >= DMA_BIT_MASK(32) || dev->bus_dma_mask) { - dev_err(dev, - "%s: overflow %pad+%zu of device mask %llx bus mask %llx\n", - caller, &dma_addr, size, - *dev->dma_mask, dev->bus_dma_mask); - } - return false; + if (!dev->dma_mask) { + dev_err_once(dev, "DMA map on device without dma_mask\n"); + } else if (*dev->dma_mask >= DMA_BIT_MASK(32) || dev->bus_dma_mask) { + dev_err_once(dev, + "overflow %pad+%zu of DMA mask %llx bus mask %llx\n", + &dma_addr, size, *dev->dma_mask, dev->bus_dma_mask); } - return true; + WARN_ON_ONCE(1); } static inline dma_addr_t phys_to_dma_direct(struct device *dev, @@ -288,8 +277,10 @@ dma_addr_t dma_direct_map_page(struct device *dev, struct page *page, phys_addr_t phys = page_to_phys(page) + offset; dma_addr_t dma_addr = phys_to_dma(dev, phys); - if (!check_addr(dev, dma_addr, size, __func__)) + if (unlikely(dev && !dma_capable(dev, dma_addr, size))) { + report_addr(dev, dma_addr, size); return DMA_MAPPING_ERROR; + } if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) dma_direct_sync_single_for_device(dev, dma_addr, size, dir); @@ -306,8 +297,11 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, BUG_ON(!sg_page(sg)); sg_dma_address(sg) = phys_to_dma(dev, sg_phys(sg)); - if (!check_addr(dev, sg_dma_address(sg), sg->length, __func__)) + if (unlikely(dev && !dma_capable(dev, sg_dma_address(sg), + sg->length))) { + report_addr(dev, sg_dma_address(sg), sg->length); return 0; + } sg_dma_len(sg) = sg->length; }