4 files changed, 7 insertions, 1 deletions

diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index cc7a8c39fb6f..b939ebb62871 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -68,6 +68,9 @@ size and dma_handle must all be the same as those passed into the
 consistent allocate.  cpu_addr must be the virtual address returned by
 the consistent allocate.
 
+Note that unlike their sibling allocation calls, these routines
+may only be called with IRQs enabled.
+
 
 Part Ib - Using small dma-coherent buffers
 ------------------------------------------
diff --git a/arch/x86/kernel/pci-dma_32.c b/arch/x86/kernel/pci-dma_32.c
index 048f09b62553..0aae2f3847a5 100644
--- a/arch/x86/kernel/pci-dma_32.c
+++ b/arch/x86/kernel/pci-dma_32.c
@@ -63,7 +63,8 @@ void dma_free_coherent(struct device *dev, size_t size,
 {
         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
         int order = get_order(size);
-        
+
+        WARN_ON(irqs_disabled());       /* for portability */
         if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
                 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
 
diff --git a/arch/x86/kernel/pci-dma_64.c b/arch/x86/kernel/pci-dma_64.c
index 29711445c818..9576a2eb375e 100644
--- a/arch/x86/kernel/pci-dma_64.c
+++ b/arch/x86/kernel/pci-dma_64.c
@@ -167,6 +167,7 @@ EXPORT_SYMBOL(dma_alloc_coherent);
 void dma_free_coherent(struct device *dev, size_t size,
                          void *vaddr, dma_addr_t bus)
 {
+        WARN_ON(irqs_disabled());       /* for portability */
         if (dma_ops->unmap_single)
                 dma_ops->unmap_single(dev, bus, size, 0);
         free_pages((unsigned long)vaddr, get_order(size));
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index a7381d55663a..30c1400e749e 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -497,6 +497,7 @@ void
 swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
                       dma_addr_t dma_handle)
 {
+        WARN_ON(irqs_disabled());
         if (!(vaddr >= (void *)io_tlb_start
                     && vaddr < (void *)io_tlb_end))
                 free_pages((unsigned long) vaddr, get_order(size));