nfp: Avoid -Wflex-array-member-not-at-end warnings

Browse source

-Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
ready to enable it globally.

There is currently an object (`tl`), at the beginning of multiple
structures, that contains a flexible structure (`struct nfp_dump_tl`),
for example:

struct nfp_dumpspec_csr {
        struct nfp_dump_tl tl;

        ...

        __be32 register_width;  /* in bits */
};

So, in order to avoid ending up with flexible-array members in the
middle of multiple other structs, we use the `struct_group_tagged()`
helper to separate the flexible array from the rest of the members
in the flexible structure:

struct nfp_dump_tl {
	struct_group_tagged(nfp_dump_tl_hdr, hdr,

	... the rest of members

	);
        char data[];
};

With the change described above, we now declare objects of the type of
the tagged struct, in this case `struct nfp_dump_tl_hdr`, without
embedding flexible arrays in the middle of another struct:

struct nfp_dumpspec_csr {
        struct nfp_dump_tl_hdr tl;

	...

        __be32 register_width;  /* in bits */
};

Also, use `container_of()` whenever we need to retrieve a pointer to
the flexible structure, through which we can access the flexible
array if needed.

So, with these changes, fix 33 of the following warnings:
drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c:58:28: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c:64:28: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c:70:28: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c:78:28: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c:87:28: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c:92:28: 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>
Link: https://lore.kernel.org/r/ZgYWlkxdrrieDYIu@neat
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

This commit is contained in:

Gustavo A. R. Silva 2024-03-28 19:17:10 -06:00 • committed by Jakub Kicinski

parent c278ec6443

commit d88cabfd9a

1 changed files with 25 additions and 16 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

41

drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c

View file