On 7/14/20 11:13 AM, Vlastimil Babka wrote: > On 7/14/20 9:34 AM, Wei Yang wrote: >> The second parameter of for_each_node_mask_to_[alloc|free] is a loop >> variant, which is not used outside of loop iteration. >> >> Let's hide this. >> >> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx> >> --- >> mm/hugetlb.c | 38 ++++++++++++++++++++------------------ >> 1 file changed, 20 insertions(+), 18 deletions(-) >> >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index 57ece74e3aae..9c3d15fb317e 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -1196,17 +1196,19 @@ static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) >> return nid; >> } >> >> -#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ >> - for (nr_nodes = nodes_weight(*mask); \ >> - nr_nodes > 0 && \ >> +#define for_each_node_mask_to_alloc(hs, node, mask) \ >> + int __nr_nodes; \ >> + for (__nr_nodes = nodes_weight(*mask); \ > > The problem with this is that if I use the macro twice in the same block, this > will redefine __nr_nodes and fail to compile, no? > In that case it's better to avoid setting up this trap, IMHO. Ah, and it will also generate the following warning, if the use of for_each* macro is not the first thing after variable declarations, but there's another statement before: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] Instead we should switch to C99 and declare it as "for (int __nr_nodes" :P
