Re: [PATCH 1/1] net/mlx4: Fix build error use array_size() helper in copy_to_user()

[Jason Gunthorpe <jgg@ziepe.ca>]

On Sat, Jan 07, 2023 at 03:27:25PM +0800, Yupeng Li wrote:
> When CONFIG_64BIT was disabled, check_copy_size() was declared with
> attribute error: copy source size is too small, array_size() for 32BIT
> was wrong size, some compiled msg with error like:
> 
>   CALL    scripts/checksyscalls.sh
>   CC [M]  drivers/net/ethernet/mellanox/mlx4/cq.o
> In file included from ./arch/x86/include/asm/preempt.h:7,
>                  from ./include/linux/preempt.h:78,
>                  from ./include/linux/percpu.h:6,
>                  from ./include/linux/context_tracking_state.h:5,
>                  from ./include/linux/hardirq.h:5,
>                  from drivers/net/ethernet/mellanox/mlx4/cq.c:37:
> In function ‘check_copy_size’,
>     inlined from ‘copy_to_user’ at ./include/linux/uaccess.h:168:6,
>     inlined from ‘mlx4_init_user_cqes’ at drivers/net/ethernet/mellanox/mlx4/cq.c:317:9,
>     inlined from ‘mlx4_cq_alloc’ at drivers/net/ethernet/mellanox/mlx4/cq.c:394:10:
> ./include/linux/thread_info.h:228:4: error: call to ‘__bad_copy_from’ declared with attribute error: copy source size is too small
>   228 |    __bad_copy_from();
>       |    ^~~~~~~~~~~~~~~~~
> make[6]: *** [scripts/Makefile.build:250：drivers/net/ethernet/mellanox/mlx4/cq.o] 错误 1
> make[5]: *** [scripts/Makefile.build:500：drivers/net/ethernet/mellanox/mlx4] 错误 2
> make[5]: *** 正在等待未完成的任务....
> make[4]: *** [scripts/Makefile.build:500：drivers/net/ethernet/mellanox] 错误 2
> make[3]: *** [scripts/Makefile.build:500：drivers/net/ethernet] 错误 2
> make[3]: *** 正在等待未完成的任务....
> make[2]: *** [scripts/Makefile.build:500：drivers/net] 错误 2
> make[2]: *** 正在等待未完成的任务....
> make[1]: *** [scripts/Makefile.build:500：drivers] 错误 2
> make: *** [Makefile:1992：.] 错误 2
> 
> Signed-off-by: Yupeng Li <liyupeng@zbhlos.com>
> Reviewed-by: Caicai <caizp2008@163.com>
> ---
>  drivers/net/ethernet/mellanox/mlx4/cq.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/cq.c b/drivers/net/ethernet/mellanox/mlx4/cq.c
> index 4d4f9cf9facb..7dadd7227480 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/cq.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/cq.c
> @@ -315,7 +315,11 @@ static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
>  		}
>  	} else {
>  		err = copy_to_user((void __user *)buf, init_ents,
> +#ifdef CONFIG_64BIT
>  				   array_size(entries, cqe_size)) ?
> +#else
> +				   entries * cqe_size) ?
> +#endif
>  			-EFAULT : 0;

This can't possibly make sense, Kees?

Jason