x86: retry allocation if failed
This patch puts in the code to retry allocation in case it fails. By its
own, it does not make much sense but making the code look like x86_64.
But later patches in this series will make we try to allocate from
zones other than DMA first, which will possibly fail.
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 debe911..11f100a 100644
--- a/arch/x86/kernel/pci-dma_32.c
+++ b/arch/x86/kernel/pci-dma_32.c
@@ -76,6 +76,8 @@
struct page *page;
dma_addr_t bus;
int order = get_order(size);
+ unsigned long dma_mask = 0;
+
/* ignore region specifiers */
gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
@@ -85,15 +87,37 @@
if (!dev)
dev = &fallback_dev;
+ dma_mask = dev->coherent_dma_mask;
+ if (dma_mask == 0)
+ dma_mask = DMA_32BIT_MASK;
+
+ again:
page = dma_alloc_pages(dev, gfp, order);
if (page == NULL)
return NULL;
- ret = page_address(page);
- bus = page_to_phys(page);
+ {
+ int high, mmu;
+ bus = page_to_phys(page);
+ ret = page_address(page);
+ high = (bus + size) >= dma_mask;
+ mmu = high;
+ if (force_iommu && !(gfp & GFP_DMA))
+ mmu = 1;
+ else if (high) {
+ free_pages((unsigned long)ret,
+ get_order(size));
- memset(ret, 0, size);
- *dma_handle = bus;
+ /* Don't use the 16MB ZONE_DMA unless absolutely
+ needed. It's better to use remapping first. */
+ if (dma_mask < DMA_32BIT_MASK && !(gfp & GFP_DMA)) {
+ gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
+ goto again;
+ }
+ }
+ memset(ret, 0, size);
+ *dma_handle = bus;
+ }
return ret;
}