| Message ID | ZrVBuiqFHAORpFxE@cute (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 0a3e6939d4b33d68bce89477b9db01d68b744749 |
| Headers | show |
| Series | [next] net/smc: Use static_assert() to check struct sizes | expand |
On 09/08/2024 00:07, Gustavo A. R. Silva wrote: > Commit 9748dbc9f265 ("net/smc: Avoid -Wflex-array-member-not-at-end > warnings") introduced tagged `struct smc_clc_v2_extension_fixed` and > `struct smc_clc_smcd_v2_extension_fixed`. We want to ensure that when > new members need to be added to the flexible structures, they are > always included within these tagged structs. > > So, we use `static_assert()` to ensure that the memory layout for > both the flexible structure and the tagged struct is the same after > any changes. Hi Gustavo, good catch. By reviewing it, it makes sense to me. Please let me give it a run with our test-suite before adding a r-b. Thanks - J > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> > --- > net/smc/smc_clc.h | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h > index 467effb50cd6..5625fda2960b 100644 > --- a/net/smc/smc_clc.h > +++ b/net/smc/smc_clc.h > @@ -145,6 +145,8 @@ struct smc_clc_v2_extension { > ); > u8 user_eids[][SMC_MAX_EID_LEN]; > }; > +static_assert(offsetof(struct smc_clc_v2_extension, user_eids) == sizeof(struct smc_clc_v2_extension_fixed), > + "struct member likely outside of struct_group_tagged()"); > > struct smc_clc_msg_proposal_prefix { /* prefix part of clc proposal message*/ > __be32 outgoing_subnet; /* subnet mask */ > @@ -169,6 +171,8 @@ struct smc_clc_smcd_v2_extension { > ); > struct smc_clc_smcd_gid_chid gidchid[]; > }; > +static_assert(offsetof(struct smc_clc_smcd_v2_extension, gidchid) == sizeof(struct smc_clc_smcd_v2_extension_fixed), > + "struct member likely outside of struct_group_tagged()"); > > struct smc_clc_msg_proposal { /* clc proposal message sent by Linux */ > struct smc_clc_msg_hdr hdr;
On 09/08/2024 00:07, Gustavo A. R. Silva wrote: > Commit 9748dbc9f265 ("net/smc: Avoid -Wflex-array-member-not-at-end > warnings") introduced tagged `struct smc_clc_v2_extension_fixed` and > `struct smc_clc_smcd_v2_extension_fixed`. We want to ensure that when > new members need to be added to the flexible structures, they are > always included within these tagged structs. > > So, we use `static_assert()` to ensure that the memory layout for > both the flexible structure and the tagged struct is the same after > any changes. Read up what the macro does. I like it. Compile tested on s390. Reviewed-by: Jan Karcher <jaka@linux.ibm.com> > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> > --- > net/smc/smc_clc.h | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h > index 467effb50cd6..5625fda2960b 100644 > --- a/net/smc/smc_clc.h > +++ b/net/smc/smc_clc.h > @@ -145,6 +145,8 @@ struct smc_clc_v2_extension { > ); > u8 user_eids[][SMC_MAX_EID_LEN]; > }; > +static_assert(offsetof(struct smc_clc_v2_extension, user_eids) == sizeof(struct smc_clc_v2_extension_fixed), > + "struct member likely outside of struct_group_tagged()"); > > struct smc_clc_msg_proposal_prefix { /* prefix part of clc proposal message*/ > __be32 outgoing_subnet; /* subnet mask */ > @@ -169,6 +171,8 @@ struct smc_clc_smcd_v2_extension { > ); > struct smc_clc_smcd_gid_chid gidchid[]; > }; > +static_assert(offsetof(struct smc_clc_smcd_v2_extension, gidchid) == sizeof(struct smc_clc_smcd_v2_extension_fixed), > + "struct member likely outside of struct_group_tagged()"); > > struct smc_clc_msg_proposal { /* clc proposal message sent by Linux */ > struct smc_clc_msg_hdr hdr;
Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski <kuba@kernel.org>: On Thu, 8 Aug 2024 16:07:54 -0600 you wrote: > Commit 9748dbc9f265 ("net/smc: Avoid -Wflex-array-member-not-at-end > warnings") introduced tagged `struct smc_clc_v2_extension_fixed` and > `struct smc_clc_smcd_v2_extension_fixed`. We want to ensure that when > new members need to be added to the flexible structures, they are > always included within these tagged structs. > > So, we use `static_assert()` to ensure that the memory layout for > both the flexible structure and the tagged struct is the same after > any changes. > > [...] Here is the summary with links: - [next] net/smc: Use static_assert() to check struct sizes https://git.kernel.org/netdev/net-next/c/0a3e6939d4b3 You are awesome, thank you!
diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h index 467effb50cd6..5625fda2960b 100644 --- a/net/smc/smc_clc.h +++ b/net/smc/smc_clc.h @@ -145,6 +145,8 @@ struct smc_clc_v2_extension { ); u8 user_eids[][SMC_MAX_EID_LEN]; }; +static_assert(offsetof(struct smc_clc_v2_extension, user_eids) == sizeof(struct smc_clc_v2_extension_fixed), + "struct member likely outside of struct_group_tagged()"); struct smc_clc_msg_proposal_prefix { /* prefix part of clc proposal message*/ __be32 outgoing_subnet; /* subnet mask */ @@ -169,6 +171,8 @@ struct smc_clc_smcd_v2_extension { ); struct smc_clc_smcd_gid_chid gidchid[]; }; +static_assert(offsetof(struct smc_clc_smcd_v2_extension, gidchid) == sizeof(struct smc_clc_smcd_v2_extension_fixed), + "struct member likely outside of struct_group_tagged()"); struct smc_clc_msg_proposal { /* clc proposal message sent by Linux */ struct smc_clc_msg_hdr hdr;
Commit 9748dbc9f265 ("net/smc: Avoid -Wflex-array-member-not-at-end warnings") introduced tagged `struct smc_clc_v2_extension_fixed` and `struct smc_clc_smcd_v2_extension_fixed`. We want to ensure that when new members need to be added to the flexible structures, they are always included within these tagged structs. So, we use `static_assert()` to ensure that the memory layout for both the flexible structure and the tagged struct is the same after any changes. Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- net/smc/smc_clc.h | 4 ++++ 1 file changed, 4 insertions(+)