@@ -307,6 +307,25 @@ bool dma_fence_begin_signalling(void)
}
EXPORT_SYMBOL(dma_fence_begin_signalling);
+/**
+ * dma_fence_assert_in_signalling_section - check fence signalling annotations
+ *
+ * Since dma_fence_begin_signalling() and dma_fence_end_signalling() are built
+ * using lockdep annotations they have limitations on how freely they can be
+ * nested. Specifically, they cannot be on both inside and outside of locked
+ * sections, which in practice means the annotations often have to be pushed out
+ * to the top level callers.
+ *
+ * To ensure low-level functions are only called with the correction
+ * annotations, this function can be used to check for that.
+ */
+void dma_fence_assert_in_signalling_section(void)
+{
+ if (!in_atomic())
+ lockdep_assert(lock_is_held(&dma_fence_lockdep_map));
+}
+EXPORT_SYMBOL(dma_fence_assert_in_signalling_section);
+
/**
* dma_fence_end_signalling - end a critical DMA fence signalling section
* @cookie: opaque cookie from dma_fence_begin_signalling()
@@ -356,6 +356,7 @@ dma_fence_get_rcu_safe(struct dma_fence __rcu **fencep)
#ifdef CONFIG_LOCKDEP
bool dma_fence_begin_signalling(void);
+void dma_fence_assert_in_signalling_section(void);
void dma_fence_end_signalling(bool cookie);
void __dma_fence_might_wait(void);
#else
@@ -363,6 +364,7 @@ static inline bool dma_fence_begin_signalling(void)
{
return true;
}
+static inline void dma_fence_assert_in_signalling_section(void) {}
static inline void dma_fence_end_signalling(bool cookie) {}
static inline void __dma_fence_might_wait(void) {}
#endif
Useful for checking for dma-fence signalling annotations since they don't quite nest as freely as we'd like to. Cc: Matthew Brost <matthew.brost@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org --- drivers/dma-buf/dma-fence.c | 19 +++++++++++++++++++ include/linux/dma-fence.h | 2 ++ 2 files changed, 21 insertions(+)