Merge branch 'for-linus-3.4' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf

Pull dma-buf updates from Sumit Semwal:
 "This includes the following key items:

   - kernel cpu access support,
   - flag-passing to dma_buf_fd,
   - relevant Documentation updates, and
   - some minor cleanups and fixes.

  These changes are needed for the drm prime/dma-buf interface code that
  Dave Airlie plans to submit in this merge window."

* 'for-linus-3.4' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf:
  dma-buf: correct dummy function declarations.
  dma-buf: document fd flags and O_CLOEXEC requirement
  dma_buf: Add documentation for the new cpu access support
  dma-buf: add support for kernel cpu access
  dma-buf: don't hold the mutex around map/unmap calls
  dma-buf: add get_dma_buf()
  dma-buf: pass flags into dma_buf_fd.
  dma-buf: add dma_data_direction to unmap dma_buf_op
  dma-buf: Move code out of mutex-protected section in dma_buf_attach()
  dma-buf: Return error instead of using a goto statement when possible
  dma-buf: Remove unneeded sanity checks
  dma-buf: Constify ops argument to dma_buf_export()

1 files changed, 141 insertions, 24 deletions

diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index e38ad243b4bb..07cbbc6fddb4 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -71,7 +71,7 @@ static inline int is_dma_buf_file(struct file *file)
  * ops, or error in allocating struct dma_buf, will return negative error.
  *
  */
-struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops,
+struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
                                 size_t size, int flags)
 {
         struct dma_buf *dmabuf;
@@ -80,7 +80,9 @@ struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops,
         if (WARN_ON(!priv || !ops
                           || !ops->map_dma_buf
                           || !ops->unmap_dma_buf
-                          || !ops->release)) {
+                          || !ops->release
+                          || !ops->kmap_atomic
+                          || !ops->kmap)) {
                 return ERR_PTR(-EINVAL);
         }
 
@@ -107,17 +109,18 @@ EXPORT_SYMBOL_GPL(dma_buf_export);
 /**
  * dma_buf_fd - returns a file descriptor for the given dma_buf
  * @dmabuf:     [in]    pointer to dma_buf for which fd is required.
+ * @flags:      [in]    flags to give to fd
  *
  * On success, returns an associated 'fd'. Else, returns error.
  */
-int dma_buf_fd(struct dma_buf *dmabuf)
+int dma_buf_fd(struct dma_buf *dmabuf, int flags)
 {
         int error, fd;
 
         if (!dmabuf || !dmabuf->file)
                 return -EINVAL;
 
-        error = get_unused_fd();
+        error = get_unused_fd_flags(flags);
         if (error < 0)
                 return error;
         fd = error;
@@ -185,17 +188,18 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
         struct dma_buf_attachment *attach;
         int ret;
 
-        if (WARN_ON(!dmabuf || !dev || !dmabuf->ops))
+        if (WARN_ON(!dmabuf || !dev))
                 return ERR_PTR(-EINVAL);
 
         attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
         if (attach == NULL)
-                goto err_alloc;
-
-        mutex_lock(&dmabuf->lock);
+                return ERR_PTR(-ENOMEM);
 
         attach->dev = dev;
         attach->dmabuf = dmabuf;
+
+        mutex_lock(&dmabuf->lock);
+
         if (dmabuf->ops->attach) {
                 ret = dmabuf->ops->attach(dmabuf, dev, attach);
                 if (ret)
@@ -206,8 +210,6 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
         mutex_unlock(&dmabuf->lock);
         return attach;
 
-err_alloc:
-        return ERR_PTR(-ENOMEM);
 err_attach:
         kfree(attach);
         mutex_unlock(&dmabuf->lock);
@@ -224,7 +226,7 @@ EXPORT_SYMBOL_GPL(dma_buf_attach);
  */
 void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
 {
-        if (WARN_ON(!dmabuf || !attach || !dmabuf->ops))
+        if (WARN_ON(!dmabuf || !attach))
                 return;
 
         mutex_lock(&dmabuf->lock);
@@ -255,13 +257,10 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
 
         might_sleep();
 
-        if (WARN_ON(!attach || !attach->dmabuf || !attach->dmabuf->ops))
+        if (WARN_ON(!attach || !attach->dmabuf))
                 return ERR_PTR(-EINVAL);
 
-        mutex_lock(&attach->dmabuf->lock);
-        if (attach->dmabuf->ops->map_dma_buf)
-                sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
-        mutex_unlock(&attach->dmabuf->lock);
+        sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
 
         return sg_table;
 }
@@ -273,19 +272,137 @@ EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
  * dma_buf_ops.
  * @attach:     [in]    attachment to unmap buffer from
  * @sg_table:   [in]    scatterlist info of the buffer to unmap
+ * @direction:  [in]    direction of DMA transfer
  *
  */
 void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
-                                struct sg_table *sg_table)
+                                struct sg_table *sg_table,
+                                enum dma_data_direction direction)
 {
-        if (WARN_ON(!attach || !attach->dmabuf || !sg_table
-                            || !attach->dmabuf->ops))
+        if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
                 return;
 
-        mutex_lock(&attach->dmabuf->lock);
-        if (attach->dmabuf->ops->unmap_dma_buf)
-                attach->dmabuf->ops->unmap_dma_buf(attach, sg_table);
-        mutex_unlock(&attach->dmabuf->lock);
-
+        attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
+                                                direction);
 }
 EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
+
+
+/**
+ * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
+ * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
+ * preparations. Coherency is only guaranteed in the specified range for the
+ * specified access direction.
+ * @dma_buf:    [in]    buffer to prepare cpu access for.
+ * @start:      [in]    start of range for cpu access.
+ * @len:        [in]    length of range for cpu access.
+ * @direction:  [in]    length of range for cpu access.
+ *
+ * Can return negative error values, returns 0 on success.
+ */
+int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
+                             enum dma_data_direction direction)
+{
+        int ret = 0;
+
+        if (WARN_ON(!dmabuf))
+                return -EINVAL;
+
+        if (dmabuf->ops->begin_cpu_access)
+                ret = dmabuf->ops->begin_cpu_access(dmabuf, start, len, direction);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
+
+/**
+ * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
+ * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
+ * actions. Coherency is only guaranteed in the specified range for the
+ * specified access direction.
+ * @dma_buf:    [in]    buffer to complete cpu access for.
+ * @start:      [in]    start of range for cpu access.
+ * @len:        [in]    length of range for cpu access.
+ * @direction:  [in]    length of range for cpu access.
+ *
+ * This call must always succeed.
+ */
+void dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
+                            enum dma_data_direction direction)
+{
+        WARN_ON(!dmabuf);
+
+        if (dmabuf->ops->end_cpu_access)
+                dmabuf->ops->end_cpu_access(dmabuf, start, len, direction);
+}
+EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
+
+/**
+ * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
+ * space. The same restrictions as for kmap_atomic and friends apply.
+ * @dma_buf:    [in]    buffer to map page from.
+ * @page_num:   [in]    page in PAGE_SIZE units to map.
+ *
+ * This call must always succeed, any necessary preparations that might fail
+ * need to be done in begin_cpu_access.
+ */
+void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
+{
+        WARN_ON(!dmabuf);
+
+        return dmabuf->ops->kmap_atomic(dmabuf, page_num);
+}
+EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
+
+/**
+ * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
+ * @dma_buf:    [in]    buffer to unmap page from.
+ * @page_num:   [in]    page in PAGE_SIZE units to unmap.
+ * @vaddr:      [in]    kernel space pointer obtained from dma_buf_kmap_atomic.
+ *
+ * This call must always succeed.
+ */
+void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
+                           void *vaddr)
+{
+        WARN_ON(!dmabuf);
+
+        if (dmabuf->ops->kunmap_atomic)
+                dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
+}
+EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
+
+/**
+ * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
+ * same restrictions as for kmap and friends apply.
+ * @dma_buf:    [in]    buffer to map page from.
+ * @page_num:   [in]    page in PAGE_SIZE units to map.
+ *
+ * This call must always succeed, any necessary preparations that might fail
+ * need to be done in begin_cpu_access.
+ */
+void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
+{
+        WARN_ON(!dmabuf);
+
+        return dmabuf->ops->kmap(dmabuf, page_num);
+}
+EXPORT_SYMBOL_GPL(dma_buf_kmap);
+
+/**
+ * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
+ * @dma_buf:    [in]    buffer to unmap page from.
+ * @page_num:   [in]    page in PAGE_SIZE units to unmap.
+ * @vaddr:      [in]    kernel space pointer obtained from dma_buf_kmap.
+ *
+ * This call must always succeed.
+ */
+void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
+                    void *vaddr)
+{
+        WARN_ON(!dmabuf);
+
+        if (dmabuf->ops->kunmap)
+                dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
+}
+EXPORT_SYMBOL_GPL(dma_buf_kunmap);