[next] uapi: target: Replace fake flex-array with flexible-array member

  Zero-length arrays as fake flexible arrays are deprecated and we are
moving towards adopting C99 flexible-array members instead.

Address the following warning found with GCC-13 and
-fstrict-flex-arrays=3 enabled:
  CC      drivers/target/target_core_user.o
drivers/target/target_core_user.c: In function ‘queue_cmd_ring’:
drivers/target/target_core_user.c:1096:15: warning: array subscript 0 is outside array bounds of ‘struct iovec[0]’ [-Warray-bounds=]
 1096 |         iov = &entry->req.iov[0];
      |               ^~~~~~~~~~~~~~~~~~
In file included from drivers/target/target_core_user.c:31:
./include/uapi/linux/target_core_user.h:122:38: note: while referencing ‘iov’
  122 |                         struct iovec iov[0];
      |                                      ^~~

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

Link: https://github.com/KSPP/linux/issues/21
Link: https://github.com/KSPP/linux/issues/270
Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 include/uapi/linux/target_core_user.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
  

On 17.03.23 17:59, Gustavo A. R. Silva wrote:
> Zero-length arrays as fake flexible arrays are deprecated and we are
> moving towards adopting C99 flexible-array members instead.
> 
> Address the following warning found with GCC-13 and
> -fstrict-flex-arrays=3 enabled:
>    CC      drivers/target/target_core_user.o
> drivers/target/target_core_user.c: In function ‘queue_cmd_ring’:
> drivers/target/target_core_user.c:1096:15: warning: array subscript 0 is outside array bounds of ‘struct iovec[0]’ [-Warray-bounds=]
>   1096 |         iov = &entry->req.iov[0];
>        |               ^~~~~~~~~~~~~~~~~~
> In file included from drivers/target/target_core_user.c:31:
> ./include/uapi/linux/target_core_user.h:122:38: note: while referencing ‘iov’
>    122 |                         struct iovec iov[0];
>        |                                      ^~~
> 
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
> 
> Link: https://github.com/KSPP/linux/issues/21
> Link: https://github.com/KSPP/linux/issues/270
> Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>   include/uapi/linux/target_core_user.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/uapi/linux/target_core_user.h b/include/uapi/linux/target_core_user.h
> index fbd8ca67e107..f925a77f19ed 100644
> --- a/include/uapi/linux/target_core_user.h
> +++ b/include/uapi/linux/target_core_user.h
> @@ -119,7 +119,7 @@ struct tcmu_cmd_entry {
>   			__u64 cdb_off;
>   			__u64 __pad1;
>   			__u64 __pad2;
> -			struct iovec iov[0];
> +			__DECLARE_FLEX_ARRAY(struct iovec, iov);
>   		} req;
>   		struct {
>   			__u8 scsi_status;

Looks good. Thank you.

Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>
  

On Fri, Mar 17, 2023 at 10:59:48AM -0600, Gustavo A. R. Silva wrote:
> Zero-length arrays as fake flexible arrays are deprecated and we are
> moving towards adopting C99 flexible-array members instead.
> 
> Address the following warning found with GCC-13 and
> -fstrict-flex-arrays=3 enabled:
>   CC      drivers/target/target_core_user.o
> drivers/target/target_core_user.c: In function ‘queue_cmd_ring’:
> drivers/target/target_core_user.c:1096:15: warning: array subscript 0 is outside array bounds of ‘struct iovec[0]’ [-Warray-bounds=]
>  1096 |         iov = &entry->req.iov[0];
>       |               ^~~~~~~~~~~~~~~~~~
> In file included from drivers/target/target_core_user.c:31:
> ./include/uapi/linux/target_core_user.h:122:38: note: while referencing ‘iov’
>   122 |                         struct iovec iov[0];
>       |                                      ^~~
> 
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
> 
> Link: https://github.com/KSPP/linux/issues/21
> Link: https://github.com/KSPP/linux/issues/270
> Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Reviewed-by: Kees Cook <keescook@chromium.org>
  

Gustavo,

> Zero-length arrays as fake flexible arrays are deprecated and we are
> moving towards adopting C99 flexible-array members instead.

Applied to 6.4/scsi-staging, thanks!
  

On Fri, 17 Mar 2023 10:59:48 -0600, Gustavo A. R. Silva wrote:

> Zero-length arrays as fake flexible arrays are deprecated and we are
> moving towards adopting C99 flexible-array members instead.
> 
> Address the following warning found with GCC-13 and
> -fstrict-flex-arrays=3 enabled:
>   CC      drivers/target/target_core_user.o
> drivers/target/target_core_user.c: In function ‘queue_cmd_ring’:
> drivers/target/target_core_user.c:1096:15: warning: array subscript 0 is outside array bounds of ‘struct iovec[0]’ [-Warray-bounds=]
>  1096 |         iov = &entry->req.iov[0];
>       |               ^~~~~~~~~~~~~~~~~~
> In file included from drivers/target/target_core_user.c:31:
> ./include/uapi/linux/target_core_user.h:122:38: note: while referencing ‘iov’
>   122 |                         struct iovec iov[0];
>       |                                      ^~~
> 
> [...]

Applied to 6.4/scsi-queue, thanks!

[1/1] uapi: target: Replace fake flex-array with flexible-array member
      https://git.kernel.org/mkp/scsi/c/5c8c74ef20e7