[PATCH v1 6/6] dma-buf: Remove internal lock

[Dmitry Osipenko]

The internal dma-buf lock isn't needed anymore because the updated
locking specification claims that dma-buf reservation must be locked
by importers, and thus, the internal data is already protected by the
reservation lock. Remove the obsoleted internal lock.

Signed-off-by: Dmitry Osipenko <dmitry.osipe...@collabora.com>
---
 drivers/dma-buf/dma-buf.c | 5 -----
 include/linux/dma-buf.h   | 9 ---------
 2 files changed, 14 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 37545ecb845a..4cc739537ebd 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -656,7 +656,6 @@ struct dma_buf *dma_buf_export(const struct 
dma_buf_export_info *exp_info)
 
        dmabuf->file = file;
 
-       mutex_init(&dmabuf->lock);
        INIT_LIST_HEAD(&dmabuf->attachments);
 
        mutex_lock(&db_list.lock);
@@ -1459,7 +1458,6 @@ int dma_buf_vmap_unlocked(struct dma_buf *dmabuf, struct 
iosys_map *map)
                return -EINVAL;
 
        dma_resv_lock(dmabuf->resv, NULL);
-       mutex_lock(&dmabuf->lock);
        if (dmabuf->vmapping_counter) {
                dmabuf->vmapping_counter++;
                BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr));
@@ -1479,7 +1477,6 @@ int dma_buf_vmap_unlocked(struct dma_buf *dmabuf, struct 
iosys_map *map)
        *map = dmabuf->vmap_ptr;
 
 out_unlock:
-       mutex_unlock(&dmabuf->lock);
        dma_resv_unlock(dmabuf->resv);
        return ret;
 }
@@ -1500,13 +1497,11 @@ void dma_buf_vunmap_unlocked(struct dma_buf *dmabuf, 
struct iosys_map *map)
        BUG_ON(!iosys_map_is_equal(&dmabuf->vmap_ptr, map));
 
        dma_resv_lock(dmabuf->resv, NULL);
-       mutex_lock(&dmabuf->lock);
        if (--dmabuf->vmapping_counter == 0) {
                if (dmabuf->ops->vunmap)
                        dmabuf->ops->vunmap(dmabuf, map);
                iosys_map_clear(&dmabuf->vmap_ptr);
        }
-       mutex_unlock(&dmabuf->lock);
        dma_resv_unlock(dmabuf->resv);
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap_unlocked, DMA_BUF);
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index da924a56d58f..abdd99042c77 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -326,15 +326,6 @@ struct dma_buf {
        /** @ops: dma_buf_ops associated with this buffer object. */
        const struct dma_buf_ops *ops;
 
-       /**
-        * @lock:
-        *
-        * Used internally to serialize list manipulation, attach/detach and
-        * vmap/unmap. Note that in many cases this is superseeded by
-        * dma_resv_lock() on @resv.
-        */
-       struct mutex lock;
-
        /**
         * @vmapping_counter:
         *
-- 
2.36.1