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

2 files changed, 16 insertions, 7 deletions

diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index d8fd6f779f79..0e266979728b 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -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;
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index c5da29ad010c..2b2fbb709242 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -277,15 +277,20 @@ 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;
 	}
 
-	WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));
+	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;
 }