ARM: DMA-Mapping: print warning when atomic coherent allocation fails

Print a loud warning when system runs out of memory from atomic DMA
coherent pool to let users notice the potential problem.

Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index d1cc9c1d3566..acced9332109 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -461,6 +461,10 @@ static void *__alloc_from_pool(size_t size, struct page **ret_page)
                 bitmap_set(pool->bitmap, pageno, count);
                 ptr = pool->vaddr + PAGE_SIZE * pageno;
                 *ret_page = pool->page + pageno;
+        } else {
+                pr_err_once("ERROR: %u KiB atomic DMA coherent pool is too small!\n"
+                            "Please increase it with coherent_pool= kernel parameter!\n",
+                            (unsigned)pool->size / 1024);
         }
         spin_unlock_irqrestore(&pool->lock, flags);