2 files changed, 55 insertions, 6 deletions

diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c
index fbb087b728dc..268ccbec88f9 100644
--- a/drivers/usb/core/buffer.c
+++ b/drivers/usb/core/buffer.c
@@ -172,3 +172,44 @@ void hcd_buffer_free(
 	}
 	dma_free_coherent(hcd->self.sysdev, size, addr, dma);
 }
+
+void *hcd_buffer_alloc_pages(struct usb_hcd *hcd,
+		size_t size, gfp_t mem_flags, dma_addr_t *dma)
+{
+	if (size == 0)
+		return NULL;
+
+	if (hcd->localmem_pool)
+		return gen_pool_dma_alloc_align(hcd->localmem_pool,
+				size, dma, PAGE_SIZE);
+
+	/* some USB hosts just use PIO */
+	if (!hcd_uses_dma(hcd)) {
+		*dma = DMA_MAPPING_ERROR;
+		return (void *)__get_free_pages(mem_flags,
+				get_order(size));
+	}
+
+	return dma_alloc_coherent(hcd->self.sysdev,
+			size, dma, mem_flags);
+}
+
+void hcd_buffer_free_pages(struct usb_hcd *hcd,
+		size_t size, void *addr, dma_addr_t dma)
+{
+	if (!addr)
+		return;
+
+	if (hcd->localmem_pool) {
+		gen_pool_free(hcd->localmem_pool,
+				(unsigned long)addr, size);
+		return;
+	}
+
+	if (!hcd_uses_dma(hcd)) {
+		free_pages((unsigned long)addr, get_order(size));
+		return;
+	}
+
+	dma_free_coherent(hcd->self.sysdev, size, addr, dma);
+}
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index e501a03d6c70..fcf68818e999 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -186,6 +186,7 @@ static int connected(struct usb_dev_state *ps)
 static void dec_usb_memory_use_count(struct usb_memory *usbm, int *count)
 {
 	struct usb_dev_state *ps = usbm->ps;
+	struct usb_hcd *hcd = bus_to_hcd(ps->dev->bus);
 	unsigned long flags;
 
 	spin_lock_irqsave(&ps->lock, flags);
@@ -194,8 +195,8 @@ static void dec_usb_memory_use_count(struct usb_memory *usbm, int *count)
 		list_del(&usbm->memlist);
 		spin_unlock_irqrestore(&ps->lock, flags);
 
-		usb_free_coherent(ps->dev, usbm->size, usbm->mem,
-				usbm->dma_handle);
+		hcd_buffer_free_pages(hcd, usbm->size,
+				usbm->mem, usbm->dma_handle);
 		usbfs_decrease_memory_usage(
 			usbm->size + sizeof(struct usb_memory));
 		kfree(usbm);
@@ -234,7 +235,7 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
 	size_t size = vma->vm_end - vma->vm_start;
 	void *mem;
 	unsigned long flags;
-	dma_addr_t dma_handle;
+	dma_addr_t dma_handle = DMA_MAPPING_ERROR;
 	int ret;
 
 	ret = usbfs_increase_memory_usage(size + sizeof(struct usb_memory));
@@ -247,8 +248,8 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
 		goto error_decrease_mem;
 	}
 
-	mem = usb_alloc_coherent(ps->dev, size, GFP_USER | __GFP_NOWARN,
-			&dma_handle);
+	mem = hcd_buffer_alloc_pages(hcd,
+			size, GFP_USER | __GFP_NOWARN, &dma_handle);
 	if (!mem) {
 		ret = -ENOMEM;
 		goto error_free_usbm;
@@ -264,7 +265,14 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
 	usbm->vma_use_count = 1;
 	INIT_LIST_HEAD(&usbm->memlist);
 
-	if (hcd->localmem_pool || !hcd_uses_dma(hcd)) {
+	/*
+	 * In DMA-unavailable cases, hcd_buffer_alloc_pages allocates
+	 * normal pages and assigns DMA_MAPPING_ERROR to dma_handle. Check
+	 * whether we are in such cases, and then use remap_pfn_range (or
+	 * dma_mmap_coherent) to map normal (or DMA) pages into the user
+	 * space, respectively.
+	 */
+	if (dma_handle == DMA_MAPPING_ERROR) {
 		if (remap_pfn_range(vma, vma->vm_start,
 				    virt_to_phys(usbm->mem) >> PAGE_SHIFT,
 				    size, vma->vm_page_prot) < 0) {