summaryrefslogtreecommitdiff
path: root/drivers/base/dma-buf.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-25 09:37:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-25 09:37:26 -0700
commitda89fb165e5e51a2ec1ff8a0ff6bc052d1068184 (patch)
tree1f15b6177a886ceef83d60c3b5a7af926442f581 /drivers/base/dma-buf.c
parentd5adf235adc8d8d67c10afd43922c92753f6be3c (diff)
parentb25b086d23eb852bf3cfdeb60409b4967ebb3c0c (diff)
Merge tag 'tag-for-linus-3.5' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf
Pull dma-buf updates from Sumit Semwal: "Here's the first signed-tag pull request for dma-buf framework. It includes the following key items: - mmap support - vmap support - related documentation updates These are needed by various drivers to allow mmap/vmap of dma-buf shared buffers. Dave Airlie has some prime patches dependent on the vmap pull as well." * tag 'tag-for-linus-3.5' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf: dma-buf: add initial vmap documentation dma-buf: minor documentation fixes. dma-buf: add vmap interface dma-buf: mmap support
Diffstat (limited to 'drivers/base/dma-buf.c')
-rw-r--r--drivers/base/dma-buf.c99
1 files changed, 98 insertions, 1 deletions
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 05c64c11bad2..24e88fe29ec1 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -44,8 +44,26 @@ static int dma_buf_release(struct inode *inode, struct file *file)
return 0;
}
+static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
+{
+ struct dma_buf *dmabuf;
+
+ if (!is_dma_buf_file(file))
+ return -EINVAL;
+
+ dmabuf = file->private_data;
+
+ /* check for overflowing the buffer's size */
+ if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
+ dmabuf->size >> PAGE_SHIFT)
+ return -EINVAL;
+
+ return dmabuf->ops->mmap(dmabuf, vma);
+}
+
static const struct file_operations dma_buf_fops = {
.release = dma_buf_release,
+ .mmap = dma_buf_mmap_internal,
};
/*
@@ -82,7 +100,8 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
|| !ops->unmap_dma_buf
|| !ops->release
|| !ops->kmap_atomic
- || !ops->kmap)) {
+ || !ops->kmap
+ || !ops->mmap)) {
return ERR_PTR(-EINVAL);
}
@@ -406,3 +425,81 @@ void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
}
EXPORT_SYMBOL_GPL(dma_buf_kunmap);
+
+
+/**
+ * dma_buf_mmap - Setup up a userspace mmap with the given vma
+ * @dmabuf: [in] buffer that should back the vma
+ * @vma: [in] vma for the mmap
+ * @pgoff: [in] offset in pages where this mmap should start within the
+ * dma-buf buffer.
+ *
+ * This function adjusts the passed in vma so that it points at the file of the
+ * dma_buf operation. It alsog adjusts the starting pgoff and does bounds
+ * checking on the size of the vma. Then it calls the exporters mmap function to
+ * set up the mapping.
+ *
+ * Can return negative error values, returns 0 on success.
+ */
+int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
+ unsigned long pgoff)
+{
+ if (WARN_ON(!dmabuf || !vma))
+ return -EINVAL;
+
+ /* check for offset overflow */
+ if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
+ return -EOVERFLOW;
+
+ /* check for overflowing the buffer's size */
+ if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
+ dmabuf->size >> PAGE_SHIFT)
+ return -EINVAL;
+
+ /* readjust the vma */
+ if (vma->vm_file)
+ fput(vma->vm_file);
+
+ vma->vm_file = dmabuf->file;
+ get_file(vma->vm_file);
+
+ vma->vm_pgoff = pgoff;
+
+ return dmabuf->ops->mmap(dmabuf, vma);
+}
+EXPORT_SYMBOL_GPL(dma_buf_mmap);
+
+/**
+ * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
+ * address space. Same restrictions as for vmap and friends apply.
+ * @dmabuf: [in] buffer to vmap
+ *
+ * This call may fail due to lack of virtual mapping address space.
+ * These calls are optional in drivers. The intended use for them
+ * is for mapping objects linear in kernel space for high use objects.
+ * Please attempt to use kmap/kunmap before thinking about these interfaces.
+ */
+void *dma_buf_vmap(struct dma_buf *dmabuf)
+{
+ if (WARN_ON(!dmabuf))
+ return NULL;
+
+ if (dmabuf->ops->vmap)
+ return dmabuf->ops->vmap(dmabuf);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(dma_buf_vmap);
+
+/**
+ * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
+ * @dmabuf: [in] buffer to vunmap
+ */
+void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
+{
+ if (WARN_ON(!dmabuf))
+ return;
+
+ if (dmabuf->ops->vunmap)
+ dmabuf->ops->vunmap(dmabuf, vaddr);
+}
+EXPORT_SYMBOL_GPL(dma_buf_vunmap);