From: <dan.j.williams@intel.com>
To: <dan.j.williams@intel.com>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
Kees Cook <kees@kernel.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>, <nvdimm@lists.linux.dev>,
<linux-acpi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-hardening@vger.kernel.org>
Subject: Re: [PATCH v3][next] acpi: nfit: intel: avoid multiple -Wflex-array-member-not-at-end warnings
Date: Wed, 25 Jun 2025 14:08:10 -0700 [thread overview]
Message-ID: <685c653a6fe42_1608bd100d0@dwillia2-xfh.jf.intel.com.notmuch> (raw)
In-Reply-To: <685c5d0062f2b_1608bd10051@dwillia2-xfh.jf.intel.com.notmuch>
dan.j.williams@ wrote:
> Gustavo A. R. Silva wrote:
> [..]
> > > I think it would be a pretty small and direct replacement:
> > >
> > > TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
> > > struct nd_intel_get_security_state cmd;
> > > ) nd_cmd = {
> > > ...
> >
> > Yes, this works. Hopefully, maintainers will comment on this and let us
> > know what they prefer. :)
>
> Hey Gustavo, apologies for the latency here. I think TRAILING_OVERLAP()
> looks lovely for this if only because I can read that and have an idea
> what it means vs wondering what this _offset_to_fam is about and needing
> to read the comment.
>
> If you can get me that patch on top of the TRAILING_OVERLAP() branch I
> can test it out and ack it to let it do in through the KSPP tree.
Just to move this along, I gave this conversion a try and all looks good
here. So feel free to fold this in and add:
Acked-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
...and take it through the KSPP tree with the TRAILING_OVERLAP() merge.
-- 8< --
diff --git a/drivers/acpi/nfit/intel.c b/drivers/acpi/nfit/intel.c
index 987d427ec2b6..c88647428715 100644
--- a/drivers/acpi/nfit/intel.c
+++ b/drivers/acpi/nfit/intel.c
@@ -55,17 +55,9 @@ static unsigned long intel_security_flags(struct nvdimm *nvdimm,
{
struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
unsigned long security_flags = 0;
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_get_security_state cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_get_security_state cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_INTEL_GET_SECURITY_STATE,
.nd_family = NVDIMM_FAMILY_INTEL,
@@ -127,17 +119,9 @@ static unsigned long intel_security_flags(struct nvdimm *nvdimm,
static int intel_security_freeze(struct nvdimm *nvdimm)
{
struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_freeze_lock cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_freeze_lock cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_INTEL_FREEZE_LOCK,
.nd_family = NVDIMM_FAMILY_INTEL,
@@ -167,17 +151,9 @@ static int intel_security_change_key(struct nvdimm *nvdimm,
unsigned int cmd = ptype == NVDIMM_MASTER ?
NVDIMM_INTEL_SET_MASTER_PASSPHRASE :
NVDIMM_INTEL_SET_PASSPHRASE;
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_set_passphrase cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_set_passphrase cmd;
+ ) nd_cmd = {
.pkg = {
.nd_family = NVDIMM_FAMILY_INTEL,
.nd_size_in = ND_INTEL_PASSPHRASE_SIZE * 2,
@@ -216,17 +192,9 @@ static int __maybe_unused intel_security_unlock(struct nvdimm *nvdimm,
const struct nvdimm_key_data *key_data)
{
struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_unlock_unit cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_unlock_unit cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_INTEL_UNLOCK_UNIT,
.nd_family = NVDIMM_FAMILY_INTEL,
@@ -262,17 +230,9 @@ static int intel_security_disable(struct nvdimm *nvdimm,
{
int rc;
struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_disable_passphrase cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_disable_passphrase cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_INTEL_DISABLE_PASSPHRASE,
.nd_family = NVDIMM_FAMILY_INTEL,
@@ -312,17 +272,9 @@ static int __maybe_unused intel_security_erase(struct nvdimm *nvdimm,
struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
unsigned int cmd = ptype == NVDIMM_MASTER ?
NVDIMM_INTEL_MASTER_SECURE_ERASE : NVDIMM_INTEL_SECURE_ERASE;
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_secure_erase cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_secure_erase cmd;
+ ) nd_cmd = {
.pkg = {
.nd_family = NVDIMM_FAMILY_INTEL,
.nd_size_in = ND_INTEL_PASSPHRASE_SIZE,
@@ -360,17 +312,9 @@ static int __maybe_unused intel_security_query_overwrite(struct nvdimm *nvdimm)
{
int rc;
struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_query_overwrite cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_query_overwrite cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_INTEL_QUERY_OVERWRITE,
.nd_family = NVDIMM_FAMILY_INTEL,
@@ -403,17 +347,9 @@ static int __maybe_unused intel_security_overwrite(struct nvdimm *nvdimm,
{
int rc;
struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_overwrite cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_overwrite cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_INTEL_OVERWRITE,
.nd_family = NVDIMM_FAMILY_INTEL,
@@ -463,17 +399,9 @@ const struct nvdimm_security_ops *intel_security_ops = &__intel_security_ops;
static int intel_bus_fwa_businfo(struct nvdimm_bus_descriptor *nd_desc,
struct nd_intel_bus_fw_activate_businfo *info)
{
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_bus_fw_activate_businfo cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_bus_fw_activate_businfo cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_BUS_INTEL_FW_ACTIVATE_BUSINFO,
.nd_family = NVDIMM_BUS_FAMILY_INTEL,
@@ -581,17 +509,9 @@ static enum nvdimm_fwa_capability intel_bus_fwa_capability(
static int intel_bus_fwa_activate(struct nvdimm_bus_descriptor *nd_desc)
{
struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_bus_fw_activate cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_bus_fw_activate cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_BUS_INTEL_FW_ACTIVATE,
.nd_family = NVDIMM_BUS_FAMILY_INTEL,
@@ -652,17 +572,9 @@ const struct nvdimm_bus_fw_ops *intel_bus_fw_ops = &__intel_bus_fw_ops;
static int intel_fwa_dimminfo(struct nvdimm *nvdimm,
struct nd_intel_fw_activate_dimminfo *info)
{
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_fw_activate_dimminfo cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_fw_activate_dimminfo cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_INTEL_FW_ACTIVATE_DIMMINFO,
.nd_family = NVDIMM_FAMILY_INTEL,
@@ -765,17 +677,9 @@ static int intel_fwa_arm(struct nvdimm *nvdimm, enum nvdimm_fwa_trigger arm)
{
struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
struct acpi_nfit_desc *acpi_desc = nfit_mem->acpi_desc;
- /*
- * This effectively creates a union between the flexible-array member
- * and any members after _offset_to_fam.
- */
- union {
- struct nd_cmd_pkg pkg;
- struct {
- u8 _offset_to_fam[offsetof(struct nd_cmd_pkg, nd_payload)];
- struct nd_intel_fw_activate_arm cmd;
- };
- } nd_cmd = {
+ TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload,
+ struct nd_intel_fw_activate_arm cmd;
+ ) nd_cmd = {
.pkg = {
.nd_command = NVDIMM_INTEL_FW_ACTIVATE_ARM,
.nd_family = NVDIMM_FAMILY_INTEL,
next prev parent reply other threads:[~2025-06-25 21:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-11 19:52 [PATCH v3][next] acpi: nfit: intel: avoid multiple -Wflex-array-member-not-at-end warnings Gustavo A. R. Silva
2025-06-24 19:46 ` Gustavo A. R. Silva
2025-06-25 16:56 ` Kees Cook
2025-06-25 17:31 ` Gustavo A. R. Silva
2025-06-25 20:33 ` dan.j.williams
2025-06-25 21:08 ` dan.j.williams [this message]
2025-06-25 21:43 ` Gustavo A. R. Silva
2025-06-25 22:24 ` dan.j.williams
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