vmalloc: use for_each_vmap_node() in purge-vmap-area

Update a __purge_vmap_area_lazy() to use introduced helper.  This is last
place in vmalloc code.  Also this patch introduces an extra function which
is node_to_id() that converts a vmap_node pointer to an index in array.

__purge_vmap_area_lazy() requires that extra function.

Link: https://lkml.kernel.org/r/20250408151549.77937-3-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Christop Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index e80783fa4d2c5c35a75c63ae2dc172390c193fb0..9eb3880887b679b1cdf8e79903a531e875a8411b 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -923,6 +923,19 @@ id_to_node(unsigned int id)
        return &vmap_nodes[id % nr_vmap_nodes];
 }
 
+static inline unsigned int
+node_to_id(struct vmap_node *node)
+{
+       /* Pointer arithmetic. */
+       unsigned int id = node - vmap_nodes;
+
+       if (likely(id < nr_vmap_nodes))
+               return id;
+
+       WARN_ONCE(1, "An address 0x%p is out-of-bounds.\n", node);
+       return 0;
+}
+
 /*
  * We use the value 0 to represent "no node", that is why
  * an encoded value will be the node-id incremented by 1.
@@ -2259,9 +2272,7 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end,
         */
        purge_nodes = CPU_MASK_NONE;
 
-       for (i = 0; i < nr_vmap_nodes; i++) {
-               vn = &vmap_nodes[i];
-
+       for_each_vmap_node(vn) {
                INIT_LIST_HEAD(&vn->purge_list);
                vn->skip_populate = full_pool_decay;
                decay_va_pool_node(vn, full_pool_decay);
@@ -2280,7 +2291,7 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end,
                end = max(end, list_last_entry(&vn->purge_list,
                        struct vmap_area, list)->va_end);
 
-               cpumask_set_cpu(i, &purge_nodes);
+               cpumask_set_cpu(node_to_id(vn), &purge_nodes);
        }
 
        nr_purge_nodes = cpumask_weight(&purge_nodes);