x86: use a fallback dev for i386
We can use a fallback dev for cases of a NULL device being passed (mostly ISA)
This comes from x86_64 implementation.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/pci-dma_32.c b/arch/x86/kernel/pci-dma_32.c
index 0d630ae..0600a37 100644
--- a/arch/x86/kernel/pci-dma_32.c
+++ b/arch/x86/kernel/pci-dma_32.c
@@ -14,6 +14,16 @@
#include <linux/module.h>
#include <asm/io.h>
+/* Dummy device used for NULL arguments (normally ISA). Better would
+ be probably a smaller DMA mask, but this is bug-to-bug compatible
+ to i386. */
+struct device fallback_dev = {
+ .bus_id = "fallback device",
+ .coherent_dma_mask = DMA_32BIT_MASK,
+ .dma_mask = &fallback_dev.coherent_dma_mask,
+};
+
+
static int dma_alloc_from_coherent_mem(struct device *dev, ssize_t size,
dma_addr_t *dma_handle, void **ret)
{
@@ -75,6 +85,9 @@
if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
gfp |= GFP_DMA;
+ if (!dev)
+ dev = &fallback_dev;
+
page = dma_alloc_pages(dev, gfp, order);
if (page == NULL)
return NULL;