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'

From: Paul E. McKenney
Date: Wed Mar 27 2019 - 15:57:33 EST


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;