| Message ID | Zed5RIGqPgxUt/9T@neat (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | [next] crypto/nx: Avoid -Wflex-array-member-not-at-end warning | expand |
On Tue, Mar 05, 2024 at 01:57:56PM -0600, 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, we are deprecating flexible-array > members in the middle of another structure. > > There is currently an object (`header`) in `struct nx842_crypto_ctx` > that contains a flexible structure (`struct nx842_crypto_header`): > > struct nx842_crypto_ctx { > ... > struct nx842_crypto_header header; > struct nx842_crypto_header_group group[NX842_CRYPTO_GROUP_MAX]; > ... > }; > > So, in order to avoid ending up with a flexible-array member in the > middle of another struct, we use the `struct_group_tagged()` helper to > separate the flexible array from the rest of the members in the flexible > structure: > > struct nx842_crypto_header { > struct_group_tagged(nx842_crypto_header_hdr, hdr, > > ... the rest of the members > > ); > struct nx842_crypto_header_group group[]; > } __packed; > > With the change described above, we can now declare an object of the > type of the tagged struct, without embedding the flexible array in the > middle of another struct: > > struct nx842_crypto_ctx { > ... > struct nx842_crypto_header_hdr header; > struct nx842_crypto_header_group group[NX842_CRYPTO_GROUP_MAX]; > ... > } __packed; > > We 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 the following warning: > > In file included from drivers/crypto/nx/nx-842.c:55: > drivers/crypto/nx/nx-842.h:174:36: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] > 174 | struct nx842_crypto_header header; > | ^~~~~~ > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> > --- > drivers/crypto/nx/nx-842.c | 6 ++++-- > drivers/crypto/nx/nx-842.h | 10 ++++++---- > 2 files changed, 10 insertions(+), 6 deletions(-) Patch applied. Thanks.
diff --git a/drivers/crypto/nx/nx-842.c b/drivers/crypto/nx/nx-842.c index 2ab90ec10e61..82214cde2bcd 100644 --- a/drivers/crypto/nx/nx-842.c +++ b/drivers/crypto/nx/nx-842.c @@ -251,7 +251,9 @@ int nx842_crypto_compress(struct crypto_tfm *tfm, u8 *dst, unsigned int *dlen) { struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm); - struct nx842_crypto_header *hdr = &ctx->header; + struct nx842_crypto_header *hdr = + container_of(&ctx->header, + struct nx842_crypto_header, hdr); struct nx842_crypto_param p; struct nx842_constraints c = *ctx->driver->constraints; unsigned int groups, hdrsize, h; @@ -490,7 +492,7 @@ int nx842_crypto_decompress(struct crypto_tfm *tfm, } memcpy(&ctx->header, src, hdr_len); - hdr = &ctx->header; + hdr = container_of(&ctx->header, struct nx842_crypto_header, hdr); for (n = 0; n < hdr->groups; n++) { /* ignore applies to last group */ diff --git a/drivers/crypto/nx/nx-842.h b/drivers/crypto/nx/nx-842.h index 7590bfb24d79..25fa70b2112c 100644 --- a/drivers/crypto/nx/nx-842.h +++ b/drivers/crypto/nx/nx-842.h @@ -157,9 +157,11 @@ struct nx842_crypto_header_group { } __packed; struct nx842_crypto_header { - __be16 magic; /* NX842_CRYPTO_MAGIC */ - __be16 ignore; /* decompressed end bytes to ignore */ - u8 groups; /* total groups in this header */ + struct_group_tagged(nx842_crypto_header_hdr, hdr, + __be16 magic; /* NX842_CRYPTO_MAGIC */ + __be16 ignore; /* decompressed end bytes to ignore */ + u8 groups; /* total groups in this header */ + ); struct nx842_crypto_header_group group[]; } __packed; @@ -171,7 +173,7 @@ struct nx842_crypto_ctx { u8 *wmem; u8 *sbounce, *dbounce; - struct nx842_crypto_header header; + struct nx842_crypto_header_hdr header; struct nx842_crypto_header_group group[NX842_CRYPTO_GROUP_MAX]; struct nx842_driver *driver;
-Wflex-array-member-not-at-end is coming in GCC-14, and we are getting ready to enable it globally. So, we are deprecating flexible-array members in the middle of another structure. There is currently an object (`header`) in `struct nx842_crypto_ctx` that contains a flexible structure (`struct nx842_crypto_header`): struct nx842_crypto_ctx { ... struct nx842_crypto_header header; struct nx842_crypto_header_group group[NX842_CRYPTO_GROUP_MAX]; ... }; So, in order to avoid ending up with a flexible-array member in the middle of another struct, we use the `struct_group_tagged()` helper to separate the flexible array from the rest of the members in the flexible structure: struct nx842_crypto_header { struct_group_tagged(nx842_crypto_header_hdr, hdr, ... the rest of the members ); struct nx842_crypto_header_group group[]; } __packed; With the change described above, we can now declare an object of the type of the tagged struct, without embedding the flexible array in the middle of another struct: struct nx842_crypto_ctx { ... struct nx842_crypto_header_hdr header; struct nx842_crypto_header_group group[NX842_CRYPTO_GROUP_MAX]; ... } __packed; We 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 the following warning: In file included from drivers/crypto/nx/nx-842.c:55: drivers/crypto/nx/nx-842.h:174:36: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] 174 | struct nx842_crypto_header header; | ^~~~~~ Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- drivers/crypto/nx/nx-842.c | 6 ++++-- drivers/crypto/nx/nx-842.h | 10 ++++++---- 2 files changed, 10 insertions(+), 6 deletions(-)