Re: [PATCH][next] smb: smb2pdu.h: Avoid -Wflex-array-member-not-at-end warnings

From: Gustavo A. R. Silva
Date: Tue Apr 23 2024 - 14:58:58 EST


Hi all,

Friendly ping: who can take this, please?

Thanks
--
Gustavo

On 11/04/24 09:35, Gustavo A. R. Silva wrote:
-Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
ready to enable it globally.

So, in order to avoid ending up with a flexible-array member in the
middle of multiple other structs, we use the `__struct_group()` helper
to separate the flexible array from the rest of the members in the
flexible structure, and use the tagged `struct create_context_hdr`
instead of `struct create_context`.

So, with these changes, fix 51 of the following warnings[1]:

fs/smb/client/../common/smb2pdu.h:1225:31: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Link: https://gist.github.com/GustavoARSilva/772526a39be3dd4db39e71497f0a9893 [1]
Link: https://github.com/KSPP/linux/issues/202
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
fs/smb/client/smb2pdu.h | 12 ++++++------
fs/smb/common/smb2pdu.h | 33 ++++++++++++++++++---------------
fs/smb/server/smb2pdu.h | 18 +++++++++---------
3 files changed, 33 insertions(+), 30 deletions(-)

diff --git a/fs/smb/client/smb2pdu.h b/fs/smb/client/smb2pdu.h
index c72a3b2886b7..1a02bd9e0c00 100644
--- a/fs/smb/client/smb2pdu.h
+++ b/fs/smb/client/smb2pdu.h
@@ -145,7 +145,7 @@ struct durable_context_v2 {
} __packed;
struct create_durable_v2 {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
struct durable_context_v2 dcontext;
} __packed;
@@ -167,7 +167,7 @@ struct durable_reconnect_context_v2_rsp {
} __packed;
struct create_durable_handle_reconnect_v2 {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
struct durable_reconnect_context_v2 dcontext;
__u8 Pad[4];
@@ -175,7 +175,7 @@ struct create_durable_handle_reconnect_v2 {
/* See MS-SMB2 2.2.13.2.5 */
struct crt_twarp_ctxt {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
__le64 Timestamp;
@@ -183,12 +183,12 @@ struct crt_twarp_ctxt {
/* See MS-SMB2 2.2.13.2.9 */
struct crt_query_id_ctxt {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
} __packed;
struct crt_sd_ctxt {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
struct smb3_sd sd;
} __packed;
@@ -415,7 +415,7 @@ struct smb2_posix_info_parsed {
};
struct smb2_create_ea_ctx {
- struct create_context ctx;
+ struct create_context_hdr ctx;
__u8 name[8];
struct smb2_file_full_ea_info ea;
} __packed;
diff --git a/fs/smb/common/smb2pdu.h b/fs/smb/common/smb2pdu.h
index 1b594307c9d5..eab9d49c63ba 100644
--- a/fs/smb/common/smb2pdu.h
+++ b/fs/smb/common/smb2pdu.h
@@ -1171,12 +1171,15 @@ struct smb2_server_client_notification {
#define SMB2_CREATE_FLAG_REPARSEPOINT 0x01
struct create_context {
- __le32 Next;
- __le16 NameOffset;
- __le16 NameLength;
- __le16 Reserved;
- __le16 DataOffset;
- __le32 DataLength;
+ /* New members must be added within the struct_group() macro below. */
+ __struct_group(create_context_hdr, hdr, __packed,
+ __le32 Next;
+ __le16 NameOffset;
+ __le16 NameLength;
+ __le16 Reserved;
+ __le16 DataOffset;
+ __le32 DataLength;
+ );
__u8 Buffer[];
} __packed;
@@ -1222,7 +1225,7 @@ struct smb2_create_rsp {
} __packed;
struct create_posix {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[16];
__le32 Mode;
__u32 Reserved;
@@ -1230,7 +1233,7 @@ struct create_posix {
/* See MS-SMB2 2.2.13.2.3 and MS-SMB2 2.2.13.2.4 */
struct create_durable {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
union {
__u8 Reserved[16];
@@ -1243,14 +1246,14 @@ struct create_durable {
/* See MS-SMB2 2.2.13.2.5 */
struct create_mxac_req {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
__le64 Timestamp;
} __packed;
/* See MS-SMB2 2.2.14.2.5 */
struct create_mxac_rsp {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
__le32 QueryStatus;
__le32 MaximalAccess;
@@ -1286,13 +1289,13 @@ struct lease_context_v2 {
} __packed;
struct create_lease {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
struct lease_context lcontext;
} __packed;
struct create_lease_v2 {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
struct lease_context_v2 lcontext;
__u8 Pad[4];
@@ -1300,7 +1303,7 @@ struct create_lease_v2 {
/* See MS-SMB2 2.2.14.2.9 */
struct create_disk_id_rsp {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
__le64 DiskFileId;
__le64 VolumeId;
@@ -1309,7 +1312,7 @@ struct create_disk_id_rsp {
/* See MS-SMB2 2.2.13.2.13 */
struct create_app_inst_id {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[16];
__le32 StructureSize; /* Must be 20 */
__u16 Reserved;
@@ -1318,7 +1321,7 @@ struct create_app_inst_id {
/* See MS-SMB2 2.2.13.2.15 */
struct create_app_inst_id_vers {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[16];
__le32 StructureSize; /* Must be 24 */
__u16 Reserved;
diff --git a/fs/smb/server/smb2pdu.h b/fs/smb/server/smb2pdu.h
index bd1d2a0e9203..643f5e1cfe35 100644
--- a/fs/smb/server/smb2pdu.h
+++ b/fs/smb/server/smb2pdu.h
@@ -64,7 +64,7 @@ struct preauth_integrity_info {
#define SMB2_SESSION_TIMEOUT (10 * HZ)
struct create_durable_req_v2 {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
__le32 Timeout;
__le32 Flags;
@@ -73,7 +73,7 @@ struct create_durable_req_v2 {
} __packed;
struct create_durable_reconn_req {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
union {
__u8 Reserved[16];
@@ -85,7 +85,7 @@ struct create_durable_reconn_req {
} __packed;
struct create_durable_reconn_v2_req {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
struct {
__u64 PersistentFileId;
@@ -96,13 +96,13 @@ struct create_durable_reconn_v2_req {
} __packed;
struct create_alloc_size_req {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
__le64 AllocationSize;
} __packed;
struct create_durable_rsp {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
union {
__u8 Reserved[8];
@@ -114,7 +114,7 @@ struct create_durable_rsp {
/* Flags */
#define SMB2_DHANDLE_FLAG_PERSISTENT 0x00000002
struct create_durable_v2_rsp {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
__le32 Timeout;
__le32 Flags;
@@ -122,7 +122,7 @@ struct create_durable_v2_rsp {
/* equivalent of the contents of SMB3.1.1 POSIX open context response */
struct create_posix_rsp {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[16];
__le32 nlink;
__le32 reparse_tag;
@@ -381,13 +381,13 @@ struct smb2_ea_info {
} __packed; /* level 15 Query */
struct create_ea_buf_req {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
struct smb2_ea_info ea;
} __packed;
struct create_sd_buf_req {
- struct create_context ccontext;
+ struct create_context_hdr ccontext;
__u8 Name[8];
struct smb_ntsd ntsd;
} __packed;