Merge remote-tracking branch 'asoc/topic/ep93xx' into asoc-next

[karo-tx-linux.git] / drivers / base / dma-buf.c

diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 2d5ac1a1842ea528d9dfd7d1cad48c42fab8cf8c..1e16cbd61da27877bf372cc90f1323d950676db2 100644 (file)
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -77,9 +77,36 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
        return dmabuf->ops->mmap(dmabuf, vma);
 }
 
+static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
+{
+       struct dma_buf *dmabuf;
+       loff_t base;
+
+       if (!is_dma_buf_file(file))
+               return -EBADF;
+
+       dmabuf = file->private_data;
+
+       /* only support discovering the end of the buffer,
+          but also allow SEEK_SET to maintain the idiomatic
+          SEEK_END(0), SEEK_CUR(0) pattern */
+       if (whence == SEEK_END)
+               base = dmabuf->size;
+       else if (whence == SEEK_SET)
+               base = 0;
+       else
+               return -EINVAL;
+
+       if (offset != 0)
+               return -EINVAL;
+
+       return base + offset;
+}
+
 static const struct file_operations dma_buf_fops = {
        .release        = dma_buf_release,
        .mmap           = dma_buf_mmap_internal,
+       .llseek         = dma_buf_llseek,
 };
 
 /*
@@ -137,6 +164,8 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
                kfree(dmabuf);
                return ERR_CAST(file);
        }
+
+       file->f_mode |= FMODE_LSEEK;
        dmabuf->file = file;
 
        mutex_init(&dmabuf->lock);