mm: percpu: use kmemleak_ignore_phys() instead of kmemleak_free()

Kmemleak recently added a rbtree to store the objects allocted with
physical address. Those objects can't be freed with kmemleak_free().

According to the comments, percpu allocations are tracked by kmemleak
separately. Kmemleak_free() was used to avoid the unnecessary
tracking. If kmemleak_free() fails, those objects would be scanned by
kmemleak, which is unnecessary but shouldn't lead to other effects.

Use kmemleak_ignore_phys() instead of kmemleak_free() for those
objects.

Link: https://lkml.kernel.org/r/[e-mail]
Fixes: 0c24e061196c ("mm: kmemleak: add rbtree and store physical address for objects allocated with PA")
Signed-off-by: Patrick Wang <[e-mail]>
Cc: Dennis Zhou <[e-mail]>
Cc: Tejun Heo <[e-mail]>
Cc: Christoph Lameter <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

mm/percpu.c

···
 			goto out_free_areas;
 		}
 		/* kmemleak tracks the percpu allocations separately */
-		kmemleak_free(ptr);
+		kmemleak_ignore_phys(__pa(ptr));
 		areas[group] = ptr;
 
 		base = min(ptr, base);
···
 				goto enomem;
 			}
 			/* kmemleak tracks the percpu allocations separately */
-			kmemleak_free(ptr);
+			kmemleak_ignore_phys(__pa(ptr));
 			pages[j++] = virt_to_page(ptr);
 		}
 	}
···
 	if (!ai || !fc)
 		panic("Failed to allocate memory for percpu areas.");
 	/* kmemleak tracks the percpu allocations separately */
-	kmemleak_free(fc);
+	kmemleak_ignore_phys(__pa(fc));
 
 	ai->dyn_size = unit_size;
 	ai->unit_size = unit_size;