dma-direct: fix zone selection after an unaddressable CMA allocation

The new dma_alloc_contiguous hides if we allocate CMA or regular
pages, and thus fails to retry a ZONE_NORMAL allocation if the CMA
allocation succeeds but isn't addressable.  That means we either fail
outright or dip into a small zone that might not succeed either.

Thanks to Hillf Danton for debugging this issue.

Fixes: b1d2dc009dec ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers")
Reported-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index d991d40..f68a62c 100644 (file)
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -965,10 +965,13 @@ static void *iommu_dma_alloc_pages(struct device *dev, size_t size,
 {
        bool coherent = dev_is_dma_coherent(dev);
        size_t alloc_size = PAGE_ALIGN(size);
+       int node = dev_to_node(dev);
        struct page *page = NULL;
        void *cpu_addr;
 
        page = dma_alloc_contiguous(dev, alloc_size, gfp);
+       if (!page)
+               page = alloc_pages_node(node, gfp, get_order(alloc_size));
        if (!page)
                return NULL;
 

diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index c05d4e6..03f8e98 100644 (file)
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -160,10 +160,7 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 static inline struct page *dma_alloc_contiguous(struct device *dev, size_t size,
                gfp_t gfp)
 {
-       int node = dev ? dev_to_node(dev) : NUMA_NO_NODE;
-       size_t align = get_order(PAGE_ALIGN(size));
-
-       return alloc_pages_node(node, gfp, align);
+       return NULL;
 }
 
 static inline void dma_free_contiguous(struct device *dev, struct page *page,

diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 2bd410f..69cfb43 100644 (file)
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -230,9 +230,7 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
  */
 struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
 {
-       int node = dev ? dev_to_node(dev) : NUMA_NO_NODE;
-       size_t count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-       size_t align = get_order(PAGE_ALIGN(size));
+       size_t count = size >> PAGE_SHIFT;
        struct page *page = NULL;
        struct cma *cma = NULL;
 
@@ -243,14 +241,12 @@ struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
 
        /* CMA can be used only in the context which permits sleeping */
        if (cma && gfpflags_allow_blocking(gfp)) {
+               size_t align = get_order(size);
                size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT);
 
                page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN);
        }
 
-       /* Fallback allocation of normal pages */
-       if (!page)
-               page = alloc_pages_node(node, gfp, align);
        return page;
 }
 

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 795c9b0..706113c 100644 (file)
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -85,6 +85,8 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
 struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
                dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 {
+       size_t alloc_size = PAGE_ALIGN(size);
+       int node = dev_to_node(dev);
        struct page *page = NULL;
        u64 phys_mask;
 
@@ -95,8 +97,14 @@ struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
        gfp &= ~__GFP_ZERO;
        gfp |= __dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
                        &phys_mask);
+       page = dma_alloc_contiguous(dev, alloc_size, gfp);
+       if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
+               dma_free_contiguous(dev, page, alloc_size);
+               page = NULL;
+       }
 again:
-       page = dma_alloc_contiguous(dev, size, gfp);
+       if (!page)
+               page = alloc_pages_node(node, gfp, get_order(alloc_size));
        if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
                dma_free_contiguous(dev, page, size);
                page = NULL;