Re: [rcu:dev.2019.03.20b 54/83] drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c:50:1: error: type defaults to 'int' in declaration of 'DEFINE_SRCU'

[Paul E. McKenney]

On Mon, Mar 25, 2019 at 02:34:27AM +0800, kbuild test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2019.03.20b
> head:   6d4434b4b4df791620743178e1419de882b44c7b
> commit: eb89abcb30733e3a2343dda23cb6d81cc17c60b3 [54/83] rcu: Forbid DEFINE{,_STATIC}_SRCU() from modules
> config: x86_64-randconfig-b0-03250021 (attached as .config)
> compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
> reproduce:
>         git checkout eb89abcb30733e3a2343dda23cb6d81cc17c60b3
>         # save the attached .config to linux build tree
>         make ARCH=x86_64 
> 
> All errors (new ones prefixed by >>):
> 
>    drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c:50:1: warning: data definition has no type or storage class
>     DEFINE_SRCU(kfd_processes_srcu);
>     ^~~~~~~~~~~
> >> drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c:50:1: error: type defaults to 'int' in declaration of 'DEFINE_SRCU' [-Werror=implicit-int]
>    drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c:50:1: warning: parameter names (without types) in function declaration
>    cc1: some warnings being treated as errors

I don't have that hardware, but does the following help?  (It at least
builds for me, but your mileage may vary.)

							Thanx, Paul

------------------------------------------------------------------------

commit b30be5a76070402912437fa23b43de11cb1973f4
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
Date:   Wed Mar 27 12:53:36 2019 -0700

    drivers/gpu/drm/amd: Dynamically allocate kfd_processes_srcu
    
    Having DEFINE_SRCU() or DEFINE_STATIC_SRCU() in a loadable module
    requires that the size of the reserved region be increased, which is
    not something we really want to be doing.  This commit therefore removes
    the DEFINE_STATIC_SRCU() from drivers/gpu/drm/amd/amdkfd/kfd_process.c in
    favor of defining kfd_processes_srcu as a simple srcu_struct, initializing
    it in amdgpu_amdkfd_init(), and cleaning it up in amdgpu_amdkfd_fini().
    
    Reported-by: kbuild test robot <lkp@xxxxxxxxx>
    Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
    Cc: Oded Gabbay <oded.gabbay@xxxxxxxxx>
    Cc: Alex Deucher <alexander.deucher@xxxxxxx>
    Cc: "Christian König" <christian.koenig@xxxxxxx
    Cc: "David (ChunMing) Zhou" <David1.Zhou@xxxxxxx>
    Cc: David Airlie <airlied@xxxxxxxx>
    Cc: Daniel Vetter <daniel@xxxxxxxx>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
index fe1d7368c1e6..eadb20dee867 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
@@ -28,6 +28,8 @@
 #include <linux/module.h>
 #include <linux/dma-buf.h>
 
+extern struct srcu_struct kfd_processes_srcu;
+
 static const unsigned int compute_vmid_bitmap = 0xFF00;
 
 /* Total memory size in system memory and all GPU VRAM. Used to
@@ -40,6 +42,8 @@ int amdgpu_amdkfd_init(void)
 	struct sysinfo si;
 	int ret;
 
+	ret = init_srcu_struct(&kfd_processes_srcu);
+	WARN_ON(ret);
 	si_meminfo(&si);
 	amdgpu_amdkfd_total_mem_size = si.totalram - si.totalhigh;
 	amdgpu_amdkfd_total_mem_size *= si.mem_unit;
@@ -57,6 +61,7 @@ int amdgpu_amdkfd_init(void)
 void amdgpu_amdkfd_fini(void)
 {
 	kgd2kfd_exit();
+	cleanup_srcu_struct(&kfd_processes_srcu);
 }
 
 void amdgpu_amdkfd_device_probe(struct amdgpu_device *adev)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index 4bdae78bab8e..98b694068b8a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -47,7 +47,7 @@ struct mm_struct;
 DEFINE_HASHTABLE(kfd_processes_table, KFD_PROCESS_TABLE_SIZE);
 static DEFINE_MUTEX(kfd_processes_mutex);
 
-DEFINE_SRCU(kfd_processes_srcu);
+struct srcu_struct kfd_processes_srcu;
 
 /* For process termination handling */
 static struct workqueue_struct *kfd_process_wq;