The dma_fence abstractions added by commit 3282d5916019 ("rust: Add
dma_fence abstractions") are compiled unconditionally, but the C
`dma_fence_*` symbols they reference live in
drivers/dma-buf/dma-fence.c, which is only built when
CONFIG_DMA_SHARED_BUFFER=y. Kernels with CONFIG_RUST=y and
CONFIG_RUST_KERNEL_DOCTESTS=y but CONFIG_DMA_SHARED_BUFFER=n fail
to link:
ld.lld: error: undefined symbol: dma_fence_release
>>> referenced by usercopy_64.c
>>> vmlinux.o:(rust_helper_dma_fence_put)
... dma_fence_signal{,_locked}, dma_fence_context_alloc,
dma_fence_init, dma_fence_{add,remove}_callback ...
Wrap the dma_fence.c helper include in the same
`pub mod dma_buf;` in rust/kernel/lib.rs with a matching #[cfg].
Fixes: 3282d5916019 ("rust: Add dma_fence abstractions")
Signed-off-by: Edwin Peer <[email protected]>
Reviewed-by: John Hubbard <[email protected]>
---
rust/helpers/helpers.c | 2 +-
rust/kernel/lib.rs | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index 609689fba3dd..2c5eecc091c4 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -57,8 +57,8 @@
#include "cred.c"
#include "device.c"
#include "dma.c"
-#include "dma_fence.c"
#ifdef CONFIG_DMA_SHARED_BUFFER
+#include "dma_fence.c"
#include "dma-resv.c"
#endif
#include "drm.c"
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 72f5527ba66c..f9ef36217bb5 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -67,6 +67,7 @@
pub mod device_id;
pub mod devres;
pub mod dma;
+#[cfg(CONFIG_DMA_SHARED_BUFFER)]
pub mod dma_buf;
pub mod driver;
#[cfg(CONFIG_DRM = "y")]
--
2.50.1 (Apple Git-155)
