Folio Free function causes build failure on kernel 5.15.206

NVIDIA Open GPU Kernel Modules Version

main/595.71.05

Operating System and Version

Slackware 15.0

Kernel Release

5.15.206

Please confirm you are running a stable release kernel (e.g. not a -rc). We do not accept bug reports for unreleased kernels.

• I am running on a stable kernel release.

Build Command

make modules

Terminal output/Build Log

 CC [M]  /root/nvidia/open-gpu-kernel-modules/kernel-open/nvidia-uvm/uvm_ats.o
/root/nvidia/open-gpu-kernel-modules/kernel-open/nvidia-uvm/uvm_pmm_gpu.c:3282:42: warning: âstruct folioâ declared inside parameter list will not be visible outside of this definition or declaration
 3282 | static void device_p2p_folio_free(struct folio *folio)
      |                                          ^~~~~
/root/nvidia/open-gpu-kernel-modules/kernel-open/nvidia-uvm/uvm_pmm_gpu.c: In function âdevice_p2p_folio_freeâ:
/root/nvidia/open-gpu-kernel-modules/kernel-open/nvidia-uvm/uvm_pmm_gpu.c:3284:32: error: invalid use of undefined type âstruct folioâ
 3284 |     device_p2p_page_free(&folio->page);
      |                                ^~
make[3]: *** [scripts/Makefile.build:289: /root/nvidia/open-gpu-kernel-modules/kernel-open/nvidia-uvm/uvm_pmm_gpu.o] Error 1
make[3]: *** Waiting for unfinished jobs....
make[2]: *** [Makefile:1924: /root/nvidia/open-gpu-kernel-modules/kernel-open] Error 2
make[2]: Leaving directory '/usr/src/linux-5.15.206'
make[1]: *** [Makefile:115: modules] Error 2
make[1]: Leaving directory '/root/nvidia/open-gpu-kernel-modules/kernel-open'
make: *** [Makefile:59: modules] Error 2

More Info

After some digging, I was able to ascertain that the conf test was getting the correct configuration value for the NV_PAGEMAP_OPS_HAS_FOLIO_FREE (#undef) compile time define. Using that knowledge, I was able to make the following change to allow it to build:

diff --git a/kernel-open/nvidia-uvm/uvm_pmm_gpu.c b/kernel-open/nvidia-uvm/uvm_pmm_gpu.c
index 373eca94..e839f648 100644
--- a/kernel-open/nvidia-uvm/uvm_pmm_gpu.c
+++ b/kernel-open/nvidia-uvm/uvm_pmm_gpu.c
@@ -3279,11 +3279,13 @@ static void device_p2p_page_free(struct page *page)
     nv_kref_put(&p2p_mem->refcount, device_p2p_page_free_wake);
 }
 
+#if defined(NV_PAGEMAP_OPS_HAS_FOLIO_FREE)
 static void device_p2p_folio_free(struct folio *folio)
 {
     device_p2p_page_free(&folio->page);
 }
 #endif
+#endif
 
 #if UVM_CDMM_PAGES_SUPPORTED()
 static void device_coherent_page_free(struct page *page)

Start in kernel-open/nvidia-uvm/uvm_pmm_gpu.c at device_p2p_folio_free and review the NV_PAGEMAP_OPS_HAS_FOLIO_FREE configuration result for kernel 5.15.206. Reproduce with make modules, then confirm the build completes on the reported kernel while preserving folio-free support where the configuration enables it.