From a61cb6017df0a9be072a35259e6e9ae7aa0ef6b3 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 6 Sep 2021 14:40:00 +0200 Subject: [PATCH 1/3] dma-mapping: fix the kerneldoc for dma_map_sg_attrs Add the missing description for the nents parameter, and fix a trivial misalignment. Fixes: fffe3cc8c219 ("dma-mapping: allow map_sg() ops to return negative error codes") Reported-by: Stephen Rothwell Signed-off-by: Christoph Hellwig --- kernel/dma/mapping.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 7ee5284bff585..06fec5547e7c7 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -206,7 +206,8 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, /** * dma_map_sg_attrs - Map the given buffer for DMA * @dev: The device for which to perform the DMA operation - * @sg: The sg_table object describing the buffer + * @sg: The sg_table object describing the buffer + * @nents: Number of entries to map * @dir: DMA direction * @attrs: Optional DMA attributes for the map operation * From 510e1a724ab1bf38150be2c1acabb303f98d0047 Mon Sep 17 00:00:00 2001 From: Hamza Mahfooz Date: Fri, 10 Sep 2021 19:53:37 -0400 Subject: [PATCH 2/3] dma-debug: prevent an error message from causing runtime problems For some drivers, that use the DMA API. This error message can be reached several millions of times per second, causing spam to the kernel's printk buffer and bringing the CPU usage up to 100% (so, it should be rate limited). However, since there is at least one driver that is in the mainline and suffers from the error condition, it is more useful to err_printk() here instead of just rate limiting the error message (in hopes that it will make it easier for other drivers that suffer from this issue to be spotted). Link: https://lkml.kernel.org/r/fd67fbac-64bf-f0ea-01e1-5938ccfab9d0@arm.com Reported-by: Jeremy Linton Signed-off-by: Hamza Mahfooz Signed-off-by: Christoph Hellwig --- kernel/dma/debug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c index 6c90c69e5311a..95445bd6eb725 100644 --- a/kernel/dma/debug.c +++ b/kernel/dma/debug.c @@ -567,7 +567,8 @@ static void add_dma_entry(struct dma_debug_entry *entry) pr_err("cacheline tracking ENOMEM, dma-debug disabled\n"); global_disable = true; } else if (rc == -EEXIST) { - pr_err("cacheline tracking EEXIST, overlapping mappings aren't supported\n"); + err_printk(entry->dev, entry, + "cacheline tracking EEXIST, overlapping mappings aren't supported\n"); } } From 59583f747664046aaae5588d56d5954fab66cce8 Mon Sep 17 00:00:00 2001 From: Andreas Larsson Date: Wed, 8 Sep 2021 09:48:22 +0200 Subject: [PATCH 3/3] sparc32: page align size in arch_dma_alloc Commit 53b7670e5735 ("sparc: factor the dma coherent mapping into helper") lost the page align for the calls to dma_make_coherent and srmmu_unmapiorange. The latter cannot handle a non page aligned len argument. Signed-off-by: Andreas Larsson Reviewed-by: Sam Ravnborg Signed-off-by: Christoph Hellwig --- arch/sparc/kernel/ioport.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/sparc/kernel/ioport.c b/arch/sparc/kernel/ioport.c index 8e1d72a167594..7ceae24b0ca99 100644 --- a/arch/sparc/kernel/ioport.c +++ b/arch/sparc/kernel/ioport.c @@ -356,7 +356,9 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, void arch_dma_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs) { - if (!sparc_dma_free_resource(cpu_addr, PAGE_ALIGN(size))) + size = PAGE_ALIGN(size); + + if (!sparc_dma_free_resource(cpu_addr, size)) return; dma_make_coherent(dma_addr, size);