On Mon, May 27, 2019 at 03:15:34PM -0300, Jason Gunthorpe wrote: > On Mon, May 20, 2019 at 01:19:02PM +0200, Michal Kubecek wrote: > > diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c > > index abac70ad5c7c..340290b883fe 100644 > > +++ 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 = round_up(attr->length, MLX5_SW_ICM_BLOCK_SIZE(dm_db->dev)); > > act_size = roundup_pow_of_two(act_size); > > It is kind of weird that we have round_up and the bitshift > version.. None of this is performance critical so why not just use > round_up everywhere? > > Ariel, it is true MLX5_SW_ICM_BLOCK_SIZE will always be a power of > two? If it weren't, the requirements from the comment above could never be satisfied as a power of two can only be a multiple of another power of two. Which also means that what the code above does is in fact equivalent to act_size = max_t(u64, roundup_pow_of_two(attr->length), MLX5_SW_ICM_BLOCK_SIZE(dm_db->dev)); or act_size = roundup_pow_of_two(max_t(u64, attr->length, MLX5_SW_ICM_BLOCK_SIZE(dm_db->dev)); Michal Kubecek
