Gustavo A. R. Silva
2025-Apr-07 19:57 UTC
[PATCH][next] drm/nouveau: chan: Avoid -Wflex-array-member-not-at-end warnings
On 07/04/25 13:50, Kees Cook wrote:> On Thu, Apr 03, 2025 at 10:45:18AM -0600, Gustavo A. R. Silva wrote: >> -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 a few on-stack definitions >> 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 warnings: >> >> drivers/gpu/drm/nouveau/nouveau_chan.c:274:37: 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_chan.c:371:46: 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_chan.c:524:42: 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 <gustavoars at kernel.org> >> --- >> drivers/gpu/drm/nouveau/nouveau_chan.c | 115 ++++++++++++------------- >> 1 file changed, 56 insertions(+), 59 deletions(-) >> >> diff --git a/drivers/gpu/drm/nouveau/nouveau_chan.c b/drivers/gpu/drm/nouveau/nouveau_chan.c >> index cd659b9fd1d9..a7e70517b7cd 100644 >> --- a/drivers/gpu/drm/nouveau/nouveau_chan.c >> +++ b/drivers/gpu/drm/nouveau/nouveau_chan.c >> @@ -270,10 +270,7 @@ nouveau_channel_ctor(struct nouveau_cli *cli, bool priv, u64 runm, >> { NV03_CHANNEL_DMA , 0 }, >> {} >> }; >> - struct { >> - struct nvif_chan_v0 chan; >> - char name[TASK_COMM_LEN+16]; >> - } args; >> + DEFINE_RAW_FLEX(struct nvif_chan_v0, args, name, TASK_COMM_LEN + 16); >> struct nvif_device *device = &cli->device; >> struct nouveau_channel *chan; >> const u64 plength = 0x10000; >> @@ -298,28 +295,28 @@ nouveau_channel_ctor(struct nouveau_cli *cli, bool priv, u64 runm, >> return ret; >> >> /* create channel object */ >> - args.chan.version = 0; >> - args.chan.namelen = sizeof(args.name); >> - args.chan.runlist = __ffs64(runm); >> - args.chan.runq = 0; >> - args.chan.priv = priv; >> - args.chan.devm = BIT(0); >> + args->version = 0; >> + args->namelen = __struct_size(args) - sizeof(*args); > > Does __struct_size(args->name) work here (and later)?Why not? I mean, this should be equivalent to `TASK_COMM_LEN+16`, I could use the latter if people prefer it (see my comments below).> >> + args->runlist = __ffs64(runm); >> + args->runq = 0; >> + args->priv = priv; >> + args->devm = BIT(0); >> if (hosts[cid].oclass < NV50_CHANNEL_GPFIFO) { >> - args.chan.vmm = 0; >> - args.chan.ctxdma = nvif_handle(&chan->push.ctxdma); >> - args.chan.offset = chan->push.addr; >> - args.chan.length = 0; >> + args->vmm = 0; >> + args->ctxdma = nvif_handle(&chan->push.ctxdma); >> + args->offset = chan->push.addr; >> + args->length = 0; >> } else { >> - args.chan.vmm = nvif_handle(&chan->vmm->vmm.object); >> + args->vmm = nvif_handle(&chan->vmm->vmm.object); >> if (hosts[cid].oclass < FERMI_CHANNEL_GPFIFO) >> - args.chan.ctxdma = nvif_handle(&chan->push.ctxdma); >> + args->ctxdma = nvif_handle(&chan->push.ctxdma); >> else >> - args.chan.ctxdma = 0; >> - args.chan.offset = ioffset + chan->push.addr; >> - args.chan.length = ilength; >> + args->ctxdma = 0; >> + args->offset = ioffset + chan->push.addr; >> + args->length = ilength; >> } >> - args.chan.huserd = 0; >> - args.chan.ouserd = 0; >> + args->huserd = 0; >> + args->ouserd = 0; >> >> /* allocate userd */ >> if (hosts[cid].oclass >= VOLTA_CHANNEL_GPFIFO_A) { >> @@ -329,27 +326,28 @@ nouveau_channel_ctor(struct nouveau_cli *cli, bool priv, u64 runm, >> if (ret) >> return ret; >> >> - args.chan.huserd = nvif_handle(&chan->mem_userd.object); >> - args.chan.ouserd = 0; >> + args->huserd = nvif_handle(&chan->mem_userd.object); >> + args->ouserd = 0; >> >> chan->userd = &chan->mem_userd.object; >> } else { >> chan->userd = &chan->user; >> } >> >> - snprintf(args.name, sizeof(args.name), "%s[%d]", current->comm, task_pid_nr(current)); >> + snprintf(args->name, __struct_size(args) - sizeof(*args), "%s[%d]", >> + current->comm, task_pid_nr(current)); >> >> ret = nvif_object_ctor(&device->object, "abi16ChanUser", 0, hosts[cid].oclass, >> - &args, sizeof(args), &chan->user); >> + args, __struct_size(args), &chan->user); >> if (ret) { >> nouveau_channel_del(pchan); >> return ret; >> } >> >> - chan->runlist = args.chan.runlist; >> - chan->chid = args.chan.chid; >> - chan->inst = args.chan.inst; >> - chan->token = args.chan.token; >> + chan->runlist = args->runlist; >> + chan->chid = args->chid; >> + chan->inst = args->inst; >> + chan->token = args->token; >> return 0; >> } >> >> @@ -367,17 +365,17 @@ nouveau_channel_init(struct nouveau_channel *chan, u32 vram, u32 gart) >> return ret; >> >> if (chan->user.oclass >= FERMI_CHANNEL_GPFIFO) { >> - struct { >> - struct nvif_event_v0 base; >> - struct nvif_chan_event_v0 host; >> - } args; >> + DEFINE_RAW_FLEX(struct nvif_event_v0, args, data, >> + sizeof(struct nvif_chan_event_v0)); >> + struct nvif_chan_event_v0 *host >> + (struct nvif_chan_event_v0 *)args->data; >> >> - args.host.version = 0; >> - args.host.type = NVIF_CHAN_EVENT_V0_KILLED; >> + host->version = 0; >> + host->type = NVIF_CHAN_EVENT_V0_KILLED; >> >> ret = nvif_event_ctor(&chan->user, "abi16ChanKilled", chan->chid, >> nouveau_channel_killed, false, >> - &args.base, sizeof(args), &chan->kill); >> + args, __struct_size(args), &chan->kill); >> if (ret == 0) >> ret = nvif_event_allow(&chan->kill); >> if (ret) { >> @@ -520,46 +518,45 @@ nouveau_channels_fini(struct nouveau_drm *drm) >> int >> nouveau_channels_init(struct nouveau_drm *drm) >> { >> - struct { >> - struct nv_device_info_v1 m; >> - struct { >> - struct nv_device_info_v1_data channels; >> - struct nv_device_info_v1_data runlists; >> - } v; >> - } args = { >> - .m.version = 1, >> - .m.count = sizeof(args.v) / sizeof(args.v.channels), > > sizeof(args.v) == sizeof(struct nv_device_info_v1_data) * 2 > > and sizeof(args.v.channels) == sizeof(struct nv_device_info_v1_data). > > Isn't this just "2"? i.e. isn't struct nv_device_info_v1::count the > counted_by for struct nv_device_info_v1::data?Yes, it's just `2`. However, I didn't want to explicitly use the magic number, in case people don't like it, as in other similar patches (in other subsystems). But, yeah, it's `2`. :) Thanks -- Gustavo> >> - .v.channels.mthd = NV_DEVICE_HOST_CHANNELS, >> - .v.runlists.mthd = NV_DEVICE_HOST_RUNLISTS, >> - }; >> + DEFINE_RAW_FLEX(struct nv_device_info_v1, args, data, 2); >> + struct nv_device_info_v1_data *channels = &args->data[0]; >> + struct nv_device_info_v1_data *runlists = &args->data[1]; >> struct nvif_object *device = &drm->client.device.object; >> int ret, i; >> >> - ret = nvif_object_mthd(device, NV_DEVICE_V0_INFO, &args, sizeof(args)); >> + args->version = 1; >> + args->count = (__struct_size(args) - sizeof(*args)) / >> + sizeof(*args->data); >> + channels->mthd = NV_DEVICE_HOST_CHANNELS; >> + runlists->mthd = NV_DEVICE_HOST_RUNLISTS; >> + >> + ret = nvif_object_mthd(device, NV_DEVICE_V0_INFO, args, >> + __struct_size(args)); >> if (ret || >> - args.v.runlists.mthd == NV_DEVICE_INFO_INVALID || !args.v.runlists.data || >> - args.v.channels.mthd == NV_DEVICE_INFO_INVALID) >> + runlists->mthd == NV_DEVICE_INFO_INVALID || !runlists->data || >> + channels->mthd == NV_DEVICE_INFO_INVALID) >> return -ENODEV; >> >> - drm->chan_nr = drm->chan_total = args.v.channels.data; >> - drm->runl_nr = fls64(args.v.runlists.data); >> + drm->chan_nr = drm->chan_total = channels->data; >> + drm->runl_nr = fls64(runlists->data); >> drm->runl = kcalloc(drm->runl_nr, sizeof(*drm->runl), GFP_KERNEL); >> if (!drm->runl) >> return -ENOMEM; >> >> if (drm->chan_nr == 0) { >> for (i = 0; i < drm->runl_nr; i++) { >> - if (!(args.v.runlists.data & BIT(i))) >> + if (!(runlists->data & BIT(i))) >> continue; >> >> - args.v.channels.mthd = NV_DEVICE_HOST_RUNLIST_CHANNELS; >> - args.v.channels.data = i; >> + channels->mthd = NV_DEVICE_HOST_RUNLIST_CHANNELS; >> + channels->data = i; >> >> - ret = nvif_object_mthd(device, NV_DEVICE_V0_INFO, &args, sizeof(args)); >> - if (ret || args.v.channels.mthd == NV_DEVICE_INFO_INVALID) >> + ret = nvif_object_mthd(device, NV_DEVICE_V0_INFO, args, >> + __struct_size(args)); >> + if (ret || channels->mthd == NV_DEVICE_INFO_INVALID) >> return -ENODEV; >> >> - drm->runl[i].chan_nr = args.v.channels.data; >> + drm->runl[i].chan_nr = channels->data; >> drm->runl[i].chan_id_base = drm->chan_total; >> drm->runl[i].context_base = dma_fence_context_alloc(drm->runl[i].chan_nr); >> > > Otherwise looks good. > > -Kees >
Kees Cook
2025-Apr-07 20:39 UTC
[PATCH][next] drm/nouveau: chan: Avoid -Wflex-array-member-not-at-end warnings
On Mon, Apr 07, 2025 at 01:57:48PM -0600, Gustavo A. R. Silva wrote:> > > On 07/04/25 13:50, Kees Cook wrote: > > On Thu, Apr 03, 2025 at 10:45:18AM -0600, Gustavo A. R. Silva wrote: > > > -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 a few on-stack definitions > > > 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 warnings: > > > > > > drivers/gpu/drm/nouveau/nouveau_chan.c:274:37: 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_chan.c:371:46: 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_chan.c:524:42: 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 <gustavoars at kernel.org> > > > --- > > > drivers/gpu/drm/nouveau/nouveau_chan.c | 115 ++++++++++++------------- > > > 1 file changed, 56 insertions(+), 59 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/nouveau/nouveau_chan.c b/drivers/gpu/drm/nouveau/nouveau_chan.c > > > index cd659b9fd1d9..a7e70517b7cd 100644 > > > --- a/drivers/gpu/drm/nouveau/nouveau_chan.c > > > +++ b/drivers/gpu/drm/nouveau/nouveau_chan.c > > > @@ -270,10 +270,7 @@ nouveau_channel_ctor(struct nouveau_cli *cli, bool priv, u64 runm, > > > { NV03_CHANNEL_DMA , 0 }, > > > {} > > > }; > > > - struct { > > > - struct nvif_chan_v0 chan; > > > - char name[TASK_COMM_LEN+16]; > > > - } args; > > > + DEFINE_RAW_FLEX(struct nvif_chan_v0, args, name, TASK_COMM_LEN + 16); > > > struct nvif_device *device = &cli->device; > > > struct nouveau_channel *chan; > > > const u64 plength = 0x10000; > > > @@ -298,28 +295,28 @@ nouveau_channel_ctor(struct nouveau_cli *cli, bool priv, u64 runm, > > > return ret; > > > /* create channel object */ > > > - args.chan.version = 0; > > > - args.chan.namelen = sizeof(args.name); > > > - args.chan.runlist = __ffs64(runm); > > > - args.chan.runq = 0; > > > - args.chan.priv = priv; > > > - args.chan.devm = BIT(0); > > > + args->version = 0; > > > + args->namelen = __struct_size(args) - sizeof(*args); > > > > Does __struct_size(args->name) work here (and later)? > > Why not?Uhm, I'm genuinely curious. I *think* it will work, but because it's within the struct, not outside of it, I'm unclear if it'll DTRT for finding the size (since __builtin_object_size() can be touchy).> I mean, this should be equivalent to `TASK_COMM_LEN+16`, I could > use the latter if people prefer it (see my comments below).Right, it should be the same. I think __struct_size(args->name) would be much more readable ... if it works. :)> > > > > > + args->runlist = __ffs64(runm); > > > + args->runq = 0; > > > + args->priv = priv; > > > + args->devm = BIT(0); > > > if (hosts[cid].oclass < NV50_CHANNEL_GPFIFO) { > > > - args.chan.vmm = 0; > > > - args.chan.ctxdma = nvif_handle(&chan->push.ctxdma); > > > - args.chan.offset = chan->push.addr; > > > - args.chan.length = 0; > > > + args->vmm = 0; > > > + args->ctxdma = nvif_handle(&chan->push.ctxdma); > > > + args->offset = chan->push.addr; > > > + args->length = 0; > > > } else { > > > - args.chan.vmm = nvif_handle(&chan->vmm->vmm.object); > > > + args->vmm = nvif_handle(&chan->vmm->vmm.object); > > > if (hosts[cid].oclass < FERMI_CHANNEL_GPFIFO) > > > - args.chan.ctxdma = nvif_handle(&chan->push.ctxdma); > > > + args->ctxdma = nvif_handle(&chan->push.ctxdma); > > > else > > > - args.chan.ctxdma = 0; > > > - args.chan.offset = ioffset + chan->push.addr; > > > - args.chan.length = ilength; > > > + args->ctxdma = 0; > > > + args->offset = ioffset + chan->push.addr; > > > + args->length = ilength; > > > } > > > - args.chan.huserd = 0; > > > - args.chan.ouserd = 0; > > > + args->huserd = 0; > > > + args->ouserd = 0; > > > /* allocate userd */ > > > if (hosts[cid].oclass >= VOLTA_CHANNEL_GPFIFO_A) { > > > @@ -329,27 +326,28 @@ nouveau_channel_ctor(struct nouveau_cli *cli, bool priv, u64 runm, > > > if (ret) > > > return ret; > > > - args.chan.huserd = nvif_handle(&chan->mem_userd.object); > > > - args.chan.ouserd = 0; > > > + args->huserd = nvif_handle(&chan->mem_userd.object); > > > + args->ouserd = 0; > > > chan->userd = &chan->mem_userd.object; > > > } else { > > > chan->userd = &chan->user; > > > } > > > - snprintf(args.name, sizeof(args.name), "%s[%d]", current->comm, task_pid_nr(current)); > > > + snprintf(args->name, __struct_size(args) - sizeof(*args), "%s[%d]", > > > + current->comm, task_pid_nr(current)); > > > ret = nvif_object_ctor(&device->object, "abi16ChanUser", 0, hosts[cid].oclass, > > > - &args, sizeof(args), &chan->user); > > > + args, __struct_size(args), &chan->user); > > > if (ret) { > > > nouveau_channel_del(pchan); > > > return ret; > > > } > > > - chan->runlist = args.chan.runlist; > > > - chan->chid = args.chan.chid; > > > - chan->inst = args.chan.inst; > > > - chan->token = args.chan.token; > > > + chan->runlist = args->runlist; > > > + chan->chid = args->chid; > > > + chan->inst = args->inst; > > > + chan->token = args->token; > > > return 0; > > > } > > > @@ -367,17 +365,17 @@ nouveau_channel_init(struct nouveau_channel *chan, u32 vram, u32 gart) > > > return ret; > > > if (chan->user.oclass >= FERMI_CHANNEL_GPFIFO) { > > > - struct { > > > - struct nvif_event_v0 base; > > > - struct nvif_chan_event_v0 host; > > > - } args; > > > + DEFINE_RAW_FLEX(struct nvif_event_v0, args, data, > > > + sizeof(struct nvif_chan_event_v0)); > > > + struct nvif_chan_event_v0 *host > > > + (struct nvif_chan_event_v0 *)args->data; > > > - args.host.version = 0; > > > - args.host.type = NVIF_CHAN_EVENT_V0_KILLED; > > > + host->version = 0; > > > + host->type = NVIF_CHAN_EVENT_V0_KILLED; > > > ret = nvif_event_ctor(&chan->user, "abi16ChanKilled", chan->chid, > > > nouveau_channel_killed, false, > > > - &args.base, sizeof(args), &chan->kill); > > > + args, __struct_size(args), &chan->kill); > > > if (ret == 0) > > > ret = nvif_event_allow(&chan->kill); > > > if (ret) { > > > @@ -520,46 +518,45 @@ nouveau_channels_fini(struct nouveau_drm *drm) > > > int > > > nouveau_channels_init(struct nouveau_drm *drm) > > > { > > > - struct { > > > - struct nv_device_info_v1 m; > > > - struct { > > > - struct nv_device_info_v1_data channels; > > > - struct nv_device_info_v1_data runlists; > > > - } v; > > > - } args = { > > > - .m.version = 1, > > > - .m.count = sizeof(args.v) / sizeof(args.v.channels), > > > > sizeof(args.v) == sizeof(struct nv_device_info_v1_data) * 2 > > > > and sizeof(args.v.channels) == sizeof(struct nv_device_info_v1_data). > > > > Isn't this just "2"? i.e. isn't struct nv_device_info_v1::count the > > counted_by for struct nv_device_info_v1::data? > > Yes, it's just `2`. However, I didn't want to explicitly use the magic > number, in case people don't like it, as in other similar patches (in > other subsystems). > > But, yeah, it's `2`. :)Okay. So if "count" is set up as a counted_by, the assignment will happen automatically (in DEFINE_FLEX -- no longer "RAW").> > Thanks > -- > Gustavo > > > > > > - .v.channels.mthd = NV_DEVICE_HOST_CHANNELS, > > > - .v.runlists.mthd = NV_DEVICE_HOST_RUNLISTS, > > > - }; > > > + DEFINE_RAW_FLEX(struct nv_device_info_v1, args, data, 2); > > > + struct nv_device_info_v1_data *channels = &args->data[0]; > > > + struct nv_device_info_v1_data *runlists = &args->data[1]; > > > struct nvif_object *device = &drm->client.device.object; > > > int ret, i; > > > - ret = nvif_object_mthd(device, NV_DEVICE_V0_INFO, &args, sizeof(args)); > > > + args->version = 1; > > > + args->count = (__struct_size(args) - sizeof(*args)) / > > > + sizeof(*args->data); > > > + channels->mthd = NV_DEVICE_HOST_CHANNELS; > > > + runlists->mthd = NV_DEVICE_HOST_RUNLISTS; > > > + > > > + ret = nvif_object_mthd(device, NV_DEVICE_V0_INFO, args, > > > + __struct_size(args)); > > > if (ret || > > > - args.v.runlists.mthd == NV_DEVICE_INFO_INVALID || !args.v.runlists.data || > > > - args.v.channels.mthd == NV_DEVICE_INFO_INVALID) > > > + runlists->mthd == NV_DEVICE_INFO_INVALID || !runlists->data || > > > + channels->mthd == NV_DEVICE_INFO_INVALID) > > > return -ENODEV; > > > - drm->chan_nr = drm->chan_total = args.v.channels.data; > > > - drm->runl_nr = fls64(args.v.runlists.data); > > > + drm->chan_nr = drm->chan_total = channels->data; > > > + drm->runl_nr = fls64(runlists->data); > > > drm->runl = kcalloc(drm->runl_nr, sizeof(*drm->runl), GFP_KERNEL); > > > if (!drm->runl) > > > return -ENOMEM; > > > if (drm->chan_nr == 0) { > > > for (i = 0; i < drm->runl_nr; i++) { > > > - if (!(args.v.runlists.data & BIT(i))) > > > + if (!(runlists->data & BIT(i))) > > > continue; > > > - args.v.channels.mthd = NV_DEVICE_HOST_RUNLIST_CHANNELS; > > > - args.v.channels.data = i; > > > + channels->mthd = NV_DEVICE_HOST_RUNLIST_CHANNELS; > > > + channels->data = i; > > > - ret = nvif_object_mthd(device, NV_DEVICE_V0_INFO, &args, sizeof(args)); > > > - if (ret || args.v.channels.mthd == NV_DEVICE_INFO_INVALID) > > > + ret = nvif_object_mthd(device, NV_DEVICE_V0_INFO, args, > > > + __struct_size(args)); > > > + if (ret || channels->mthd == NV_DEVICE_INFO_INVALID) > > > return -ENODEV; > > > - drm->runl[i].chan_nr = args.v.channels.data; > > > + drm->runl[i].chan_nr = channels->data; > > > drm->runl[i].chan_id_base = drm->chan_total; > > > drm->runl[i].context_base = dma_fence_context_alloc(drm->runl[i].chan_nr); > > > > Otherwise looks good. > > > > -Kees > > >-- Kees Cook