3 files changed, 52 insertions, 7 deletions

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 9b21469482ae..08b4c5209384 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -196,6 +196,7 @@ config CMA
 	bool "Contiguous Memory Allocator (EXPERIMENTAL)"
 	depends on HAVE_DMA_CONTIGUOUS && HAVE_MEMBLOCK && EXPERIMENTAL
 	select MIGRATION
+	select MEMORY_ISOLATION
 	help
 	  This enables the Contiguous Memory Allocator which allows drivers
 	  to allocate big physically-contiguous blocks of memory for use with
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index d91a3a0b2325..deb4a456cf83 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -156,9 +156,7 @@ static int dev_mkdir(const char *name, umode_t mode)
 	if (!err)
 		/* mark as kernel-created inode */
 		dentry->d_inode->i_private = &thread;
-	dput(dentry);
-	mutex_unlock(&path.dentry->d_inode->i_mutex);
-	path_put(&path);
+	done_path_create(&path, dentry);
 	return err;
 }
 
@@ -218,10 +216,7 @@ static int handle_create(const char *nodename, umode_t mode, struct device *dev)
 		/* mark as kernel-created inode */
 		dentry->d_inode->i_private = &thread;
 	}
-	dput(dentry);
-
-	mutex_unlock(&path.dentry->d_inode->i_mutex);
-	path_put(&path);
+	done_path_create(&path, dentry);
 	return err;
 }
 
diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index 6f3676f1559f..3fbedc75e7c5 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -10,6 +10,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
 #include <linux/gfp.h>
+#include <asm-generic/dma-coherent.h>
 
 /*
  * Managed DMA API
@@ -217,4 +218,52 @@ void dmam_release_declared_memory(struct device *dev)
 }
 EXPORT_SYMBOL(dmam_release_declared_memory);
 
+/*
+ * Create scatter-list for the already allocated DMA buffer.
+ */
+int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
+		 void *cpu_addr, dma_addr_t handle, size_t size)
+{
+	struct page *page = virt_to_page(cpu_addr);
+	int ret;
+
+	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+	if (unlikely(ret))
+		return ret;
+
+	sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
+	return 0;
+}
+EXPORT_SYMBOL(dma_common_get_sgtable);
+
 #endif
+
+/*
+ * Create userspace mapping for the DMA-coherent memory.
+ */
+int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
+		    void *cpu_addr, dma_addr_t dma_addr, size_t size)
+{
+	int ret = -ENXIO;
+#ifdef CONFIG_MMU
+	unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
+	unsigned long off = vma->vm_pgoff;
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
+		return ret;
+
+	if (off < count && user_count <= (count - off)) {
+		ret = remap_pfn_range(vma, vma->vm_start,
+				      pfn + off,
+				      user_count << PAGE_SHIFT,
+				      vma->vm_page_prot);
+	}
+#endif	/* CONFIG_MMU */
+
+	return ret;
+}
+EXPORT_SYMBOL(dma_common_mmap);