crypto: qat - Use static_assert() to check struct sizes

[PATCH][next] crypto: qat - Use static_assert() to check struct sizes

Posted by Gustavo A. R. Silva 1 year, 6 months ago

Commit 140e4c85d540 ("crypto: qat - Avoid -Wflex-array-member-not-at-end
warnings") introduced tagged `struct qat_alg_buf_list_hdr`. We want to
ensure that when new members need to be added to the flexible structure,
they are always included within this tagged struct.

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>
---
 drivers/crypto/intel/qat/qat_common/qat_bl.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/crypto/intel/qat/qat_common/qat_bl.h b/drivers/crypto/intel/qat/qat_common/qat_bl.h
index 85bc32a9ec0e..3f5b79015400 100644
--- a/drivers/crypto/intel/qat/qat_common/qat_bl.h
+++ b/drivers/crypto/intel/qat/qat_common/qat_bl.h
@@ -23,6 +23,8 @@ struct qat_alg_buf_list {
 	);
 	struct qat_alg_buf buffers[];
 } __packed;
+static_assert(offsetof(struct qat_alg_buf_list, buffers) == sizeof(struct qat_alg_buf_list_hdr),
+	      "struct member likely outside of __struct_group()");
 
 struct qat_alg_fixed_buf_list {
 	struct qat_alg_buf_list_hdr sgl_hdr;
-- 
2.34.1

Re: [PATCH][next] crypto: qat - Use static_assert() to check struct sizes

Posted by Herbert Xu 1 year, 5 months ago

On Thu, Aug 08, 2024 at 04:05:26PM -0600, Gustavo A. R. Silva wrote:
> Commit 140e4c85d540 ("crypto: qat - Avoid -Wflex-array-member-not-at-end
> warnings") introduced tagged `struct qat_alg_buf_list_hdr`. We want to
> ensure that when new members need to be added to the flexible structure,
> they are always included within this tagged struct.
> 
> 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>
> ---
>  drivers/crypto/intel/qat/qat_common/qat_bl.h | 2 ++
>  1 file changed, 2 insertions(+)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH][next] crypto: qat - Use static_assert() to check struct sizes

Posted by Cabiddu, Giovanni 1 year, 5 months ago

On Thu, Aug 08, 2024 at 04:05:26PM -0600, Gustavo A. R. Silva wrote:
> Commit 140e4c85d540 ("crypto: qat - Avoid -Wflex-array-member-not-at-end
> warnings") introduced tagged `struct qat_alg_buf_list_hdr`. We want to
> ensure that when new members need to be added to the flexible structure,
> they are always included within this tagged struct.
> 
> 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>
Acked-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>