[PATCH][next] drm/nouveau: fifo: Avoid -Wflex-array-member-not-at-end warning

[Gustavo A. R. Silva]

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of
a flexible structure where the size of the flexible-array member
is known at compile-time, and refactor the rest of the code,
accordingly.

So, with these changes, fix the following warning:

drivers/gpu/drm/nouveau/nvif/fifo.c:29:42: 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 <gustavo...@kernel.org>
---
 drivers/gpu/drm/nouveau/nvif/fifo.c | 32 ++++++++++++-----------------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nvif/fifo.c 
b/drivers/gpu/drm/nouveau/nvif/fifo.c
index a463289962b2..f8772340fec4 100644
--- a/drivers/gpu/drm/nouveau/nvif/fifo.c
+++ b/drivers/gpu/drm/nouveau/nvif/fifo.c
@@ -25,33 +25,28 @@ static int
 nvif_fifo_runlists(struct nvif_device *device)
 {
        struct nvif_object *object = &device->object;
-       struct {
-               struct nv_device_info_v1 m;
-               struct {
-                       struct nv_device_info_v1_data runlists;
-                       struct nv_device_info_v1_data runlist[64];
-               } v;
-       } *a;
+       DEFINE_RAW_FLEX(struct nv_device_info_v1, a, data, 65);
+       struct nv_device_info_v1_data *runlists = &a->data[0];
+       struct nv_device_info_v1_data *runlist = &a->data[1];
+       const u8 rl_cnt = (__struct_size(a) - sizeof(*a)) / sizeof(*a->data) - 
1;
        int ret, i;
 
        if (device->runlist)
                return 0;
 
-       if (!(a = kmalloc(sizeof(*a), GFP_KERNEL)))
-               return -ENOMEM;
-       a->m.version = 1;
-       a->m.count = sizeof(a->v) / sizeof(a->v.runlists);
-       a->v.runlists.mthd = NV_DEVICE_HOST_RUNLISTS;
-       for (i = 0; i < ARRAY_SIZE(a->v.runlist); i++) {
-               a->v.runlist[i].mthd = NV_DEVICE_HOST_RUNLIST_ENGINES;
-               a->v.runlist[i].data = i;
+       a->version = 1;
+       a->count = (__struct_size(a) - sizeof(*a)) / sizeof(*a->data);
+       runlists->mthd = NV_DEVICE_HOST_RUNLISTS;
+       for (i = 0; i < rl_cnt; i++) {
+               runlist[i].mthd = NV_DEVICE_HOST_RUNLIST_ENGINES;
+               runlist[i].data = i;
        }
 
        ret = nvif_object_mthd(object, NV_DEVICE_V0_INFO, a, sizeof(*a));
        if (ret)
                goto done;
 
-       device->runlists = fls64(a->v.runlists.data);
+       device->runlists = fls64(runlists->data);
        device->runlist = kcalloc(device->runlists, sizeof(*device->runlist),
                                  GFP_KERNEL);
        if (!device->runlist) {
@@ -60,12 +55,11 @@ nvif_fifo_runlists(struct nvif_device *device)
        }
 
        for (i = 0; i < device->runlists; i++) {
-               if (a->v.runlist[i].mthd != NV_DEVICE_INFO_INVALID)
-                       device->runlist[i].engines = a->v.runlist[i].data;
+               if (runlist[i].mthd != NV_DEVICE_INFO_INVALID)
+                       device->runlist[i].engines = runlist[i].data;
        }
 
 done:
-       kfree(a);
        return ret;
 }
 
-- 
2.43.0