Commit 2b54ac9e authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'dma-mapping-6.19-2026-01-30' of... 

Merge tag 'dma-mapping-6.19-2026-01-30' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux

Pull dma-mapping fixes from Marek Szyprowski:

 - important fix for ARM 32-bit based systems using cma= kernel
   parameter (Oreoluwa Babatunde)

 - a fix for the corner case of the DMA atomic pool based allocations
   (Sai Sree Kartheek Adivi)

* tag 'dma-mapping-6.19-2026-01-30' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
  dma/pool: distinguish between missing and exhausted atomic pools
  of: reserved_mem: Allow reserved_mem framework detect "cma=" kernel param
parents d941a3f6 56c430c7

drivers/of/of_reserved_mem.c

+17 −2
Original line number Diff line number Diff line
@@ -157,13 +157,19 @@ static int __init __reserved_mem_reserve_reg(unsigned long node, 
	phys_addr_t base, size;

	int i, len;

	const __be32 *prop;

	bool nomap;

	bool nomap, default_cma;



	prop = of_flat_dt_get_addr_size_prop(node, "reg", &len);

	if (!prop)

		return -ENOENT;



	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;

	default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);



	if (default_cma && cma_skip_dt_default_reserved_mem()) {

		pr_err("Skipping dt linux,cma-default for \"cma=\" kernel param.\n");

		return -EINVAL;

	}



	for (i = 0; i < len; i++) {

		u64 b, s;
@@ -248,10 +254,13 @@ void __init fdt_scan_reserved_mem_reg_nodes(void) 


	fdt_for_each_subnode(child, fdt, node) {

		const char *uname;

		bool default_cma = of_get_flat_dt_prop(child, "linux,cma-default", NULL);

		u64 b, s;



		if (!of_fdt_device_is_available(fdt, child))

			continue;

		if (default_cma && cma_skip_dt_default_reserved_mem())

			continue;



		if (!of_flat_dt_get_addr_size(child, "reg", &b, &s))

			continue;
@@ -389,7 +398,7 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam 
	phys_addr_t base = 0, align = 0, size;

	int i, len;

	const __be32 *prop;

	bool nomap;

	bool nomap, default_cma;

	int ret;



	prop = of_get_flat_dt_prop(node, "size", &len);
@@ -413,6 +422,12 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam 
	}



	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;

	default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);



	if (default_cma && cma_skip_dt_default_reserved_mem()) {

		pr_err("Skipping dt linux,cma-default for \"cma=\" kernel param.\n");

		return -EINVAL;

	}



	/* Need adjust the alignment to satisfy the CMA requirement */

	if (IS_ENABLED(CONFIG_CMA)

include/linux/cma.h

+9 −0
Original line number Diff line number Diff line
@@ -57,6 +57,15 @@ extern bool cma_intersects(struct cma *cma, unsigned long start, unsigned long e 


extern void cma_reserve_pages_on_error(struct cma *cma);



#ifdef CONFIG_DMA_CMA

extern bool cma_skip_dt_default_reserved_mem(void);

#else

static inline bool cma_skip_dt_default_reserved_mem(void)

{

	return false;

}

#endif



#ifdef CONFIG_CMA

struct folio *cma_alloc_folio(struct cma *cma, int order, gfp_t gfp);

bool cma_free_folio(struct cma *cma, const struct folio *folio);

kernel/dma/contiguous.c

+10 −6
Original line number Diff line number Diff line
@@ -91,6 +91,16 @@ static int __init early_cma(char *p) 
}

early_param("cma", early_cma);



/*

 * cma_skip_dt_default_reserved_mem - This is called from the

 * reserved_mem framework to detect if the default cma region is being

 * set by the "cma=" kernel parameter.

 */

bool __init cma_skip_dt_default_reserved_mem(void)

{

	return size_cmdline != -1;

}



#ifdef CONFIG_DMA_NUMA_CMA



static struct cma *dma_contiguous_numa_area[MAX_NUMNODES];
@@ -470,12 +480,6 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem) 
	struct cma *cma;

	int err;



	if (size_cmdline != -1 && default_cma) {

		pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n",

			rmem->name);

		return -EBUSY;

	}



	if (!of_get_flat_dt_prop(node, "reusable", NULL) ||

	    of_get_flat_dt_prop(node, "no-map", NULL))

		return -EINVAL;

kernel/dma/pool.c

+6 −1
Original line number Diff line number Diff line
@@ -277,14 +277,19 @@ struct page *dma_alloc_from_pool(struct device *dev, size_t size, 
{

	struct gen_pool *pool = NULL;

	struct page *page;

	bool pool_found = false;



	while ((pool = dma_guess_pool(pool, gfp))) {

		pool_found = true;

		page = __dma_alloc_from_pool(dev, size, pool, cpu_addr,

					     phys_addr_ok);

		if (page)

			return page;

	}



	if (pool_found)

		WARN(!(gfp & __GFP_NOWARN), "DMA pool exhausted for %s\n", dev_name(dev));

	else

		WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));

	return NULL;

}