iommu/dma: Avoid unlikely high-order allocations

[firefly-linux-kernel-4.4.55.git] / drivers / iommu / dma-iommu.c

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 3a20db4f8604f77d7bd374c9b9278f65a8c2cb5c..2e7417f98116a5fde3af403a62d6635f4c600938 100644 (file)
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -21,10 +21,13 @@
 
 #include <linux/device.h>
 #include <linux/dma-iommu.h>
+#include <linux/gfp.h>
 #include <linux/huge_mm.h>
 #include <linux/iommu.h>
 #include <linux/iova.h>
 #include <linux/mm.h>
+#include <linux/scatterlist.h>
+#include <linux/vmalloc.h>
 
 int iommu_dma_init(void)
 {
@@ -191,6 +194,7 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count, gfp_t gfp)
 {
        struct page **pages;
        unsigned int i = 0, array_size = count * sizeof(*pages);
+       unsigned int order = MAX_ORDER;
 
        if (array_size <= PAGE_SIZE)
                pages = kzalloc(array_size, GFP_KERNEL);
@@ -204,14 +208,15 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count, gfp_t gfp)
 
        while (count) {
                struct page *page = NULL;
-               int j, order = __fls(count);
+               int j;
 
                /*
                 * Higher-order allocations are a convenience rather
                 * than a necessity, hence using __GFP_NORETRY until
                 * falling back to single-page allocations.
                 */
-               for (order = min(order, MAX_ORDER); order > 0; order--) {
+               for (order = min_t(unsigned int, order, __fls(count));
+                    order > 0; order--) {
                        page = alloc_pages(gfp | __GFP_NORETRY, order);
                        if (!page)
                                continue;