unimore/kernel-hacking-2024-linux-steffo
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nfp: Avoid -Wflex-array-member-not-at-end warnings

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-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
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41
drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c
View file

@ -34,8 +34,11 @@ enum nfp_dumpspec_type {
/* generic type plus length */ /* generic type plus length */
struct nfp_dump_tl { struct nfp_dump_tl {
__be32 type; /* New members must be added within the struct_group() macro below. */
__be32 length; /* chunk length to follow, aligned to 8 bytes */ struct_group_tagged(nfp_dump_tl_hdr, hdr,
__be32 type;
__be32 length; /* chunk length to follow, aligned to 8 bytes */
);
char data[]; char data[];
}; };
@ -55,19 +58,19 @@ struct nfp_dump_common_cpp {
/* CSR dumpables */ /* CSR dumpables */
struct nfp_dumpspec_csr { struct nfp_dumpspec_csr {
struct nfp_dump_tl tl; struct nfp_dump_tl_hdr tl;
struct nfp_dump_common_cpp cpp; struct nfp_dump_common_cpp cpp;
__be32 register_width; /* in bits */ __be32 register_width; /* in bits */
}; };
struct nfp_dumpspec_rtsym { struct nfp_dumpspec_rtsym {
struct nfp_dump_tl tl; struct nfp_dump_tl_hdr tl;
char rtsym[]; char rtsym[];
}; };
/* header for register dumpable */ /* header for register dumpable */
struct nfp_dump_csr { struct nfp_dump_csr {
struct nfp_dump_tl tl; struct nfp_dump_tl_hdr tl;
struct nfp_dump_common_cpp cpp; struct nfp_dump_common_cpp cpp;
__be32 register_width; /* in bits */ __be32 register_width; /* in bits */
__be32 error; /* error code encountered while reading */ __be32 error; /* error code encountered while reading */
@ -75,7 +78,7 @@ struct nfp_dump_csr {
}; };
struct nfp_dump_rtsym { struct nfp_dump_rtsym {
struct nfp_dump_tl tl; struct nfp_dump_tl_hdr tl;
struct nfp_dump_common_cpp cpp; struct nfp_dump_common_cpp cpp;
__be32 error; /* error code encountered while reading */ __be32 error; /* error code encountered while reading */
u8 padded_name_length; /* pad so data starts at 8 byte boundary */ u8 padded_name_length; /* pad so data starts at 8 byte boundary */
@ -84,12 +87,12 @@ struct nfp_dump_rtsym {
}; };
struct nfp_dump_prolog { struct nfp_dump_prolog {
struct nfp_dump_tl tl; struct nfp_dump_tl_hdr tl;
__be32 dump_level; __be32 dump_level;
}; };
struct nfp_dump_error { struct nfp_dump_error {
struct nfp_dump_tl tl; struct nfp_dump_tl_hdr tl;
__be32 error; __be32 error;
char padding[4]; char padding[4];
char spec[]; char spec[];
@ -449,6 +452,8 @@ static int
nfp_dump_csr_range(struct nfp_pf *pf, struct nfp_dumpspec_csr *spec_csr, nfp_dump_csr_range(struct nfp_pf *pf, struct nfp_dumpspec_csr *spec_csr,
struct nfp_dump_state *dump) struct nfp_dump_state *dump)
{ {
struct nfp_dump_tl *spec_csr_tl =
container_of(&spec_csr->tl, struct nfp_dump_tl, hdr);
struct nfp_dump_csr *dump_header = dump->p; struct nfp_dump_csr *dump_header = dump->p;
u32 reg_sz, header_size, total_size; u32 reg_sz, header_size, total_size;
u32 cpp_rd_addr, max_rd_addr; u32 cpp_rd_addr, max_rd_addr;
@ -458,7 +463,7 @@ nfp_dump_csr_range(struct nfp_pf *pf, struct nfp_dumpspec_csr *spec_csr,
int err; int err;
if (!nfp_csr_spec_valid(spec_csr)) if (!nfp_csr_spec_valid(spec_csr))
return nfp_dump_error_tlv(&spec_csr->tl, -EINVAL, dump); return nfp_dump_error_tlv(spec_csr_tl, -EINVAL, dump);
reg_sz = be32_to_cpu(spec_csr->register_width) / BITS_PER_BYTE; reg_sz = be32_to_cpu(spec_csr->register_width) / BITS_PER_BYTE;
header_size = ALIGN8(sizeof(*dump_header)); header_size = ALIGN8(sizeof(*dump_header));
@ -466,7 +471,7 @@ nfp_dump_csr_range(struct nfp_pf *pf, struct nfp_dumpspec_csr *spec_csr,
ALIGN8(be32_to_cpu(spec_csr->cpp.dump_length)); ALIGN8(be32_to_cpu(spec_csr->cpp.dump_length));
dest = dump->p + header_size; dest = dump->p + header_size;
err = nfp_add_tlv(be32_to_cpu(spec_csr->tl.type), total_size, dump); err = nfp_add_tlv(be32_to_cpu(spec_csr_tl->type), total_size, dump);
if (err) if (err)
return err; return err;
@ -552,6 +557,8 @@ nfp_dump_indirect_csr_range(struct nfp_pf *pf,
struct nfp_dumpspec_csr *spec_csr, struct nfp_dumpspec_csr *spec_csr,
struct nfp_dump_state *dump) struct nfp_dump_state *dump)
{ {
struct nfp_dump_tl *spec_csr_tl =
container_of(&spec_csr->tl, struct nfp_dump_tl, hdr);
struct nfp_dump_csr *dump_header = dump->p; struct nfp_dump_csr *dump_header = dump->p;
u32 reg_sz, header_size, total_size; u32 reg_sz, header_size, total_size;
u32 cpp_rd_addr, max_rd_addr; u32 cpp_rd_addr, max_rd_addr;
@ -560,7 +567,7 @@ nfp_dump_indirect_csr_range(struct nfp_pf *pf,
int err; int err;
if (!nfp_csr_spec_valid(spec_csr)) if (!nfp_csr_spec_valid(spec_csr))
return nfp_dump_error_tlv(&spec_csr->tl, -EINVAL, dump); return nfp_dump_error_tlv(spec_csr_tl, -EINVAL, dump);
reg_sz = be32_to_cpu(spec_csr->register_width) / BITS_PER_BYTE; reg_sz = be32_to_cpu(spec_csr->register_width) / BITS_PER_BYTE;
header_size = ALIGN8(sizeof(*dump_header)); header_size = ALIGN8(sizeof(*dump_header));
@ -569,7 +576,7 @@ nfp_dump_indirect_csr_range(struct nfp_pf *pf,
total_size = header_size + ALIGN8(reg_data_length); total_size = header_size + ALIGN8(reg_data_length);
dest = dump->p + header_size; dest = dump->p + header_size;
err = nfp_add_tlv(be32_to_cpu(spec_csr->tl.type), total_size, dump); err = nfp_add_tlv(be32_to_cpu(spec_csr_tl->type), total_size, dump);
if (err) if (err)
return err; return err;
@ -597,6 +604,8 @@ static int
nfp_dump_single_rtsym(struct nfp_pf *pf, struct nfp_dumpspec_rtsym *spec, nfp_dump_single_rtsym(struct nfp_pf *pf, struct nfp_dumpspec_rtsym *spec,
struct nfp_dump_state *dump) struct nfp_dump_state *dump)
{ {
struct nfp_dump_tl *spec_tl =
container_of(&spec->tl, struct nfp_dump_tl, hdr);
struct nfp_dump_rtsym *dump_header = dump->p; struct nfp_dump_rtsym *dump_header = dump->p;
struct nfp_dumpspec_cpp_isl_id cpp_params; struct nfp_dumpspec_cpp_isl_id cpp_params;
struct nfp_rtsym_table *rtbl = pf->rtbl; struct nfp_rtsym_table *rtbl = pf->rtbl;
@ -607,14 +616,14 @@ nfp_dump_single_rtsym(struct nfp_pf *pf, struct nfp_dumpspec_rtsym *spec,
void *dest; void *dest;
int err; int err;
tl_len = be32_to_cpu(spec->tl.length); tl_len = be32_to_cpu(spec_tl->length);
key_len = strnlen(spec->rtsym, tl_len); key_len = strnlen(spec->rtsym, tl_len);
if (key_len == tl_len) if (key_len == tl_len)
return nfp_dump_error_tlv(&spec->tl, -EINVAL, dump); return nfp_dump_error_tlv(spec_tl, -EINVAL, dump);
sym = nfp_rtsym_lookup(rtbl, spec->rtsym); sym = nfp_rtsym_lookup(rtbl, spec->rtsym);
if (!sym) if (!sym)
return nfp_dump_error_tlv(&spec->tl, -ENOENT, dump); return nfp_dump_error_tlv(spec_tl, -ENOENT, dump);
sym_size = nfp_rtsym_size(sym); sym_size = nfp_rtsym_size(sym);
header_size = header_size =
@ -622,7 +631,7 @@ nfp_dump_single_rtsym(struct nfp_pf *pf, struct nfp_dumpspec_rtsym *spec,
total_size = header_size + ALIGN8(sym_size); total_size = header_size + ALIGN8(sym_size);
dest = dump->p + header_size; dest = dump->p + header_size;
err = nfp_add_tlv(be32_to_cpu(spec->tl.type), total_size, dump); err = nfp_add_tlv(be32_to_cpu(spec_tl->type), total_size, dump);
if (err) if (err)
return err; return err;