dma-buf: use reservation objects

This allows reservation objects to be used in dma-buf. it's required
for implementing polling support on the fences that belong to a dma-buf.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com> #drivers/media/v4l2-core/
Acked-by: Thomas Hellstrom <thellstrom@vmware.com> #drivers/gpu/drm/ttm
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net> #drivers/gpu/drm/armada/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 840c7fa80983..cd40ca22911f 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -25,10 +25,12 @@
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/dma-buf.h>
+#include <linux/fence.h>
 #include <linux/anon_inodes.h>
 #include <linux/export.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
+#include <linux/reservation.h>
 
 static inline int is_dma_buf_file(struct file *);
 
@@ -56,6 +58,9 @@ static int dma_buf_release(struct inode *inode, struct file *file)
         list_del(&dmabuf->list_node);
         mutex_unlock(&db_list.lock);
 
+        if (dmabuf->resv == (struct reservation_object *)&dmabuf[1])
+                reservation_object_fini(dmabuf->resv);
+
         kfree(dmabuf);
         return 0;
 }
@@ -128,6 +133,7 @@ static inline int is_dma_buf_file(struct file *file)
  * @size:       [in]    Size of the buffer
  * @flags:      [in]    mode flags for the file.
  * @exp_name:   [in]    name of the exporting module - useful for debugging.
+ * @resv:       [in]    reservation-object, NULL to allocate default one.
  *
  * Returns, on success, a newly created dma_buf object, which wraps the
  * supplied private data and operations for dma_buf_ops. On either missing
@@ -135,10 +141,17 @@ static inline int is_dma_buf_file(struct file *file)
  *
  */
 struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
-                                size_t size, int flags, const char *exp_name)
+                                size_t size, int flags, const char *exp_name,
+                                struct reservation_object *resv)
 {
         struct dma_buf *dmabuf;
         struct file *file;
+        size_t alloc_size = sizeof(struct dma_buf);
+        if (!resv)
+                alloc_size += sizeof(struct reservation_object);
+        else
+                /* prevent &dma_buf[1] == dma_buf->resv */
+                alloc_size += 1;
 
         if (WARN_ON(!priv || !ops
                           || !ops->map_dma_buf
@@ -150,7 +163,7 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
                 return ERR_PTR(-EINVAL);
         }
 
-        dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL);
+        dmabuf = kzalloc(alloc_size, GFP_KERNEL);
         if (dmabuf == NULL)
                 return ERR_PTR(-ENOMEM);
 
@@ -158,6 +171,11 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
         dmabuf->ops = ops;
         dmabuf->size = size;
         dmabuf->exp_name = exp_name;
+        if (!resv) {
+                resv = (struct reservation_object *)&dmabuf[1];
+                reservation_object_init(resv);
+        }
+        dmabuf->resv = resv;
 
         file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
         if (IS_ERR(file)) {