Bluetooth: L2CAP: Avoid -Wflex-array-member-not-at-end warnings
-Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
ready to enable it globally.
There are currently a couple of objects (`req` and `rsp`), in a couple
of structures, that contain flexible structures (`struct l2cap_ecred_conn_req`
and `struct l2cap_ecred_conn_rsp`), for example:
struct l2cap_ecred_rsp_data {
struct {
struct l2cap_ecred_conn_rsp rsp;
__le16 scid[L2CAP_ECRED_MAX_CID];
} __packed pdu;
int count;
};
in the struct above, `struct l2cap_ecred_conn_rsp` is a flexible
structure:
struct l2cap_ecred_conn_rsp {
__le16 mtu;
__le16 mps;
__le16 credits;
__le16 result;
__le16 dcid[];
};
So, in order to avoid ending up with a flexible-array member in the
middle of another structure, we use the `struct_group_tagged()` (and
`__struct_group()` when the flexible structure is `__packed`) helper
to separate the flexible array from the rest of the members in the
flexible structure:
struct l2cap_ecred_conn_rsp {
struct_group_tagged(l2cap_ecred_conn_rsp_hdr, hdr,
... the rest of members
);
__le16 dcid[];
};
With the change described above, we now declare objects of the type of
the tagged struct, in this example `struct l2cap_ecred_conn_rsp_hdr`,
without embedding flexible arrays in the middle of other structures:
struct l2cap_ecred_rsp_data {
struct {
struct l2cap_ecred_conn_rsp_hdr rsp;
__le16 scid[L2CAP_ECRED_MAX_CID];
} __packed pdu;
int count;
};
Also, when the flexible-array member needs to be accessed, we use
`container_of()` to retrieve a pointer to the flexible structure.
We also use the `DEFINE_RAW_FLEX()` helper for a couple of on-stack
definitions of a flexible structure where the size of the flexible-array
member is known at compile-time.
So, with these changes, fix the following warnings:
net/bluetooth/l2cap_core.c:1260:45: warning: structure containing a
flexible array member is not at the end of another structure
[-Wflex-array-member-not-at-end]
net/bluetooth/l2cap_core.c:3740:45: warning: structure containing a
flexible array member is not at the end of another structure
[-Wflex-array-member-not-at-end]
net/bluetooth/l2cap_core.c:4999:45: warning: structure containing a
flexible array member is not at the end of another structure
[-Wflex-array-member-not-at-end]
net/bluetooth/l2cap_core.c:7116:47: warning: structure containing a
flexible array member is not at the end of another structure
[-Wflex-array-member-not-at-end]
Link: https://github.com/KSPP/linux/issues/202
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2 files changed
