linux/include
Gustavo A. R. Silva 1c08108f30 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>
2024-05-14 10:51:04 -04:00
..
acpi ACPI: bus: allow _UID matching for integer zero 2024-04-08 16:57:51 +02:00
asm-generic sched: Add missing memory barrier in switch_mm_cid 2024-04-16 13:59:45 +02:00
clocksource
crypto
drm
dt-bindings
keys
kunit
kvm
linux net: revert partially applied PHY topology series 2024-05-13 18:35:02 -07:00
math-emu
media
memory
misc
net Bluetooth: L2CAP: Avoid -Wflex-array-member-not-at-end warnings 2024-05-14 10:51:04 -04:00
pcmcia
ras
rdma
rv
scsi
soc
sound ASoC: Fixes for v6.9 2024-05-01 18:05:13 +02:00
target
trace net/ipv4: add tracepoint for icmp_send 2024-05-08 10:39:26 +01:00
uapi net: revert partially applied PHY topology series 2024-05-13 18:35:02 -07:00
ufs
vdso vdso: Use CONFIG_PAGE_SHIFT in vdso/datapage.h 2024-04-03 21:50:04 +02:00
video
xen