On Wed, May 22, 2019 at 02:54:50PM -0400, Steven Rostedt wrote:
> 
> From: Steven Rostedt (VMware) <rost...@goodmis.org>
> 
> When testing 32 bit x86, my build failed with:
> 
>   ERROR: "__udivdi3" [drivers/infiniband/hw/mlx5/mlx5_ib.ko] undefined!
> 
> It appears that a few non-ULL roundup() calls were made, which uses a
> normal division against a 64 bit number. This is fine for x86_64, but
> on 32 bit x86, it causes the compiler to look for a helper function
> __udivdi3, which we do not have in the kernel, and thus fails to build.
> 
> Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org>
> ---
...
> diff --git a/drivers/infiniband/hw/mlx5/main.c 
> b/drivers/infiniband/hw/mlx5/main.c
> index abac70ad5c7c..40d4c5f7ea43 100644
> --- a/drivers/infiniband/hw/mlx5/main.c
> +++ b/drivers/infiniband/hw/mlx5/main.c
> @@ -2344,7 +2344,7 @@ static int handle_alloc_dm_sw_icm(struct ib_ucontext 
> *ctx,
>       /* Allocation size must a multiple of the basic block size
>        * and a power of 2.
>        */
> -     act_size = roundup(attr->length, MLX5_SW_ICM_BLOCK_SIZE(dm_db->dev));
> +     act_size = DIV_ROUND_UP_ULL(attr->length, 
> MLX5_SW_ICM_BLOCK_SIZE(dm_db->dev));
>       act_size = roundup_pow_of_two(act_size);
>  
>       dm->size = act_size;

This seems wrong: roundup() rounds up to a multiple of second argument
but DIV_ROUND_UP_ULL() would divide with rounding up.

Michal Kubecek

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