[PATCH][next] drm/nouveau: Avoid multiple -Wflex-array-member-not-at-end warnings
Gustavo A. R. Silva
gustavoars at kernel.org
Wed Feb 12 09:01:26 UTC 2025
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.
So, in order to avoid ending up with flexible-array members in the
middle of other structs, we use the `struct_group_tagged()` helper
to separate the flexible arrays from the rest of the members in the
flexible structures. We then use the newly created tagged `struct
nvif_ioctl_v0_hdr` and `struct nvif_ioctl_mthd_v0_hdr` to replace the
type of the objects causing trouble in multiple structures.
We also want to ensure that when new members need to be added to the
flexible structures, they are always included within the newly created
tagged structs. For this, we use `static_assert()`. This ensures that the
memory layout for both the flexible structure and the new tagged struct
is the same after any changes.
So, with these changes, fix the following warnings:
drivers/gpu/drm/nouveau/nvif/object.c:60:38: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/gpu/drm/nouveau/nvif/object.c:233:38: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/gpu/drm/nouveau/nvif/object.c:214:38: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/gpu/drm/nouveau/nvif/object.c:152:38: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/gpu/drm/nouveau/nvif/object.c:138:38: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/gpu/drm/nouveau/nvif/object.c:104:38: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/gpu/drm/nouveau/nouveau_svm.c:83:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/gpu/drm/nouveau/nouveau_svm.c:82:30: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
Signed-off-by: Gustavo A. R. Silva <gustavoars at kernel.org>
---
drivers/gpu/drm/nouveau/include/nvif/ioctl.h | 32 +++++++++++++-------
drivers/gpu/drm/nouveau/nouveau_svm.c | 4 +--
drivers/gpu/drm/nouveau/nvif/object.c | 12 ++++----
3 files changed, 29 insertions(+), 19 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/include/nvif/ioctl.h b/drivers/gpu/drm/nouveau/include/nvif/ioctl.h
index e825c8a1d9ca..00015412cb3e 100644
--- a/drivers/gpu/drm/nouveau/include/nvif/ioctl.h
+++ b/drivers/gpu/drm/nouveau/include/nvif/ioctl.h
@@ -3,25 +3,30 @@
#define __NVIF_IOCTL_H__
struct nvif_ioctl_v0 {
- __u8 version;
+ /* New members MUST be added within the struct_group() macro below. */
+ struct_group_tagged(nvif_ioctl_v0_hdr, __hdr,
+ __u8 version;
#define NVIF_IOCTL_V0_SCLASS 0x01
#define NVIF_IOCTL_V0_NEW 0x02
#define NVIF_IOCTL_V0_DEL 0x03
#define NVIF_IOCTL_V0_MTHD 0x04
#define NVIF_IOCTL_V0_MAP 0x07
#define NVIF_IOCTL_V0_UNMAP 0x08
- __u8 type;
- __u8 pad02[4];
+ __u8 type;
+ __u8 pad02[4];
#define NVIF_IOCTL_V0_OWNER_NVIF 0x00
#define NVIF_IOCTL_V0_OWNER_ANY 0xff
- __u8 owner;
+ __u8 owner;
#define NVIF_IOCTL_V0_ROUTE_NVIF 0x00
#define NVIF_IOCTL_V0_ROUTE_HIDDEN 0xff
- __u8 route;
- __u64 token;
- __u64 object;
+ __u8 route;
+ __u64 token;
+ __u64 object;
+ );
__u8 data[]; /* ioctl data (below) */
};
+static_assert(offsetof(struct nvif_ioctl_v0, data) == sizeof(struct nvif_ioctl_v0_hdr),
+ "struct member likely outside of struct_group()");
struct nvif_ioctl_sclass_v0 {
/* nvif_ioctl ... */
@@ -51,12 +56,17 @@ struct nvif_ioctl_del {
};
struct nvif_ioctl_mthd_v0 {
- /* nvif_ioctl ... */
- __u8 version;
- __u8 method;
- __u8 pad02[6];
+ /* New members MUST be added within the struct_group() macro below. */
+ struct_group_tagged(nvif_ioctl_mthd_v0_hdr, __hdr,
+ /* nvif_ioctl ... */
+ __u8 version;
+ __u8 method;
+ __u8 pad02[6];
+ );
__u8 data[]; /* method data (class.h) */
};
+static_assert(offsetof(struct nvif_ioctl_mthd_v0, data) == sizeof(struct nvif_ioctl_mthd_v0_hdr),
+ "struct member likely outside of struct_group()");
struct nvif_ioctl_map_v0 {
/* nvif_ioctl ... */
diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
index b4da82ddbb6b..fc64c3d3169e 100644
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -79,8 +79,8 @@ struct nouveau_svm {
#define SVM_ERR(s,f,a...) NV_WARN((s)->drm, "svm: "f"\n", ##a)
struct nouveau_pfnmap_args {
- struct nvif_ioctl_v0 i;
- struct nvif_ioctl_mthd_v0 m;
+ struct nvif_ioctl_v0_hdr i;
+ struct nvif_ioctl_mthd_v0_hdr m;
struct nvif_vmm_pfnmap_v0 p;
};
diff --git a/drivers/gpu/drm/nouveau/nvif/object.c b/drivers/gpu/drm/nouveau/nvif/object.c
index 0b87278ac0f8..70af63d70976 100644
--- a/drivers/gpu/drm/nouveau/nvif/object.c
+++ b/drivers/gpu/drm/nouveau/nvif/object.c
@@ -57,7 +57,7 @@ int
nvif_object_sclass_get(struct nvif_object *object, struct nvif_sclass **psclass)
{
struct {
- struct nvif_ioctl_v0 ioctl;
+ struct nvif_ioctl_v0_hdr ioctl;
struct nvif_ioctl_sclass_v0 sclass;
} *args = NULL;
int ret, cnt = 0, i;
@@ -101,7 +101,7 @@ int
nvif_object_mthd(struct nvif_object *object, u32 mthd, void *data, u32 size)
{
struct {
- struct nvif_ioctl_v0 ioctl;
+ struct nvif_ioctl_v0_hdr ioctl;
struct nvif_ioctl_mthd_v0 mthd;
} *args;
u32 args_size;
@@ -135,7 +135,7 @@ void
nvif_object_unmap_handle(struct nvif_object *object)
{
struct {
- struct nvif_ioctl_v0 ioctl;
+ struct nvif_ioctl_v0_hdr ioctl;
struct nvif_ioctl_unmap unmap;
} args = {
.ioctl.type = NVIF_IOCTL_V0_UNMAP,
@@ -149,7 +149,7 @@ nvif_object_map_handle(struct nvif_object *object, void *argv, u32 argc,
u64 *handle, u64 *length)
{
struct {
- struct nvif_ioctl_v0 ioctl;
+ struct nvif_ioctl_v0_hdr ioctl;
struct nvif_ioctl_map_v0 map;
} *args;
u32 argn = sizeof(*args) + argc;
@@ -211,7 +211,7 @@ void
nvif_object_dtor(struct nvif_object *object)
{
struct {
- struct nvif_ioctl_v0 ioctl;
+ struct nvif_ioctl_v0_hdr ioctl;
struct nvif_ioctl_del del;
} args = {
.ioctl.type = NVIF_IOCTL_V0_DEL,
@@ -230,7 +230,7 @@ nvif_object_ctor(struct nvif_object *parent, const char *name, u32 handle,
s32 oclass, void *data, u32 size, struct nvif_object *object)
{
struct {
- struct nvif_ioctl_v0 ioctl;
+ struct nvif_ioctl_v0_hdr ioctl;
struct nvif_ioctl_new_v0 new;
} *args;
int ret = 0;
--
2.43.0
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