Re: regression in ath10k dma allocation

[Hillf Danton <hdanton@sina.com>]

On Sat, 17 Aug 2019 00:42:48 +0200 Tobias Klausmann wrote:
>Hi Nicolin,
>
>On 17.08.19 00:25, Nicolin Chen wrote:
>> Hi Tobias
>>
>> On Fri, Aug 16, 2019 at 10:16:45PM +0200, Tobias Klausmann wrote:
>>>> do you have CONFIG_DMA_CMA set in your config?  If not please make sure
>>>> you have this commit in your testing tree, and if the problem still
>>>> persists it would be a little odd and we'd have to dig deeper:
>>>>
>>>> commit dd3dcede9fa0a0b661ac1f24843f4a1b1317fdb6
>>>> Author: Nicolin Chen <nicoleotsuka@gmail.com>
>>>> Date:   Wed May 29 17:54:25 2019 -0700
>>>>
>>>>       dma-contiguous: fix !CONFIG_DMA_CMA version of dma_{alloc, free}_contiguous()
>>> yes CONFIG_DMA_CMA is set (=y, see attached config), the commit you mention
>>> above is included, if you have any hints how to go forward, please let me
>>> know!
>> For CONFIG_DMA_CMA=y, by judging the log with error code -12, I
>> feel this one should work for you. Would you please check if it
>> is included or try it out otherwise?
>>
>> dma-contiguous: do not overwrite align in dma_alloc_contiguous()
>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=c6622a425acd1d2f3a443cd39b490a8777b622d7
>
>
>Thanks for the hint, yet the commit is included and does not fix the 
>problem!
>
Hi Tobias

Two minor diffs below in hope that they might make sense.

1, fallback unless dma coherent ok.

--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -246,6 +246,10 @@ struct page *dma_alloc_contiguous(struct
 		size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT);
 
 		page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN);
+		if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
+			dma_free_contiguous(dev, page, size);
+			page = NULL;
+		}
 	}
 
 	/* Fallback allocation of normal pages */
--

2, cleanup: cma unless contiguous

--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -234,18 +234,13 @@ struct page *dma_alloc_contiguous(struct
 	size_t count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	size_t align = get_order(PAGE_ALIGN(size));
 	struct page *page = NULL;
-	struct cma *cma = NULL;
-
-	if (dev && dev->cma_area)
-		cma = dev->cma_area;
-	else if (count > 1)
-		cma = dma_contiguous_default_area;
 
 	/* CMA can be used only in the context which permits sleeping */
-	if (cma && gfpflags_allow_blocking(gfp)) {
+	if (count > 1 && gfpflags_allow_blocking(gfp)) {
 		size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT);
 
-		page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN);
+		page = cma_alloc(dev_get_cma_area(dev), count, cma_align,
+							gfp & __GFP_NOWARN);
 		if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
 			dma_free_contiguous(dev, page, size);
 			page = NULL;
--

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