Re: [PATCH v4 1/2] memblock: drop for_each_memblock_type() and open code its users

[Mike Rapoport]

Hi Tarun,

Please for the next time add the cover-letter when sending more than one
patch.

On Thu, Oct 08, 2026 at 07:08:27PM +0000, Tarun Sahu wrote:
> for_each_memblock_type() always starts the iteration at index 0 and its
> body is a trivial 'for' loop, so it hides very little. It also gets in
> the way of iterating from an arbitrary index, which the next patch
> needs.
> 
> Remove the macro and open code its three users: memblock_add_range(),
> memblock_isolate_range() and memblock_dump(). While at it, move the
> region pointer into the loop body scope.
> 
> No functional change.
> 
> Reviewed-by: Pratyush Yadav <pratyush@xxxxxxxxxx>
> Signed-off-by: Tarun Sahu <tarunsahu@xxxxxxxxxx>
> ---
>  mm/memblock.c | 17 ++++++-----------
>  1 file changed, 6 insertions(+), 11 deletions(-)
> 
> diff --git a/mm/memblock.c b/mm/memblock.c
> index f5aaa38cfa31..59dda7d085f3 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -155,11 +155,6 @@ struct memblock_type physmem = {
>   */
>  static __refdata struct memblock_type *memblock_memory = &memblock.memory;
>  
> -#define for_each_memblock_type(i, memblock_type, rgn)			\
> -	for (i = 0, rgn = &memblock_type->regions[0];			\
> -	     i < memblock_type->cnt;					\
> -	     i++, rgn = &memblock_type->regions[i])
> -
>  #define memblock_dbg(fmt, ...)						\
>  	do {								\
>  		if (memblock_debug)					\
> @@ -615,7 +610,6 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>  	phys_addr_t obase = base;
>  	phys_addr_t end = base + memblock_cap_size(base, &size);
>  	int idx, nr_new, start_rgn = -1, end_rgn;
> -	struct memblock_region *rgn;
>  
>  	if (!size)
>  		return 0;
> @@ -651,7 +645,8 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>  	base = obase;
>  	nr_new = 0;
>  
> -	for_each_memblock_type(idx, type, rgn) {
> +	for (idx = 0; idx < type->cnt; idx++) {
> +		struct memblock_region *rgn = &type->regions[idx];
>  		phys_addr_t rbase = rgn->base;
>  		phys_addr_t rend = rbase + rgn->size;
>  
> @@ -815,7 +810,6 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
>  {
>  	phys_addr_t end = base + memblock_cap_size(base, &size);
>  	int idx;
> -	struct memblock_region *rgn;
>  
>  	*start_rgn = *end_rgn = 0;
>  
> @@ -827,7 +821,8 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
>  		if (memblock_double_array(type, base, size) < 0)
>  			return -ENOMEM;
>  
> -	for_each_memblock_type(idx, type, rgn) {
> +	for (idx = 0; idx < type->cnt; idx++) {
> +		struct memblock_region *rgn = &type->regions[idx];
>  		phys_addr_t rbase = rgn->base;
>  		phys_addr_t rend = rbase + rgn->size;
>  
> @@ -2194,11 +2189,11 @@ static void __init_memblock memblock_dump(struct memblock_type *type)
>  	phys_addr_t base, end, size;
>  	enum memblock_flags flags;
>  	int idx;
> -	struct memblock_region *rgn;
>  
>  	pr_info(" %s.cnt  = 0x%lx\n", type->name, type->cnt);
>  
> -	for_each_memblock_type(idx, type, rgn) {
> +	for (idx = 0; idx < type->cnt; idx++) {
> +		struct memblock_region *rgn = &type->regions[idx];
>  		char nid_buf[32] = "";
>  
>  		base = rgn->base;
> -- 
> 2.56.0.385.gd3acb90ef8-goog
> 

-- 
Sincerely yours,
Mike.