mm/vmalloc: explicitly identify vm_map_ram area when shown in /proc/vmcoreinfo

Now, by marking VMAP_RAM in vmap_area->flags for vm_map_ram area, we can
clearly differentiate it with other vmalloc areas.  So identify
vm_map_area area by checking VMAP_RAM of vmap_area->flags when shown in
/proc/vmcoreinfo.

Meanwhile, the code comment above vm_map_ram area checking in s_show() is
not needed any more, remove it here.

Link: https://lkml.kernel.org/r/20230206084020.174506-5-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 7188a47..87d71c7 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4152,14 +4152,11 @@ static int s_show(struct seq_file *m, void *p)
 
        va = list_entry(p, struct vmap_area, list);
 
-       /*
-        * s_show can encounter race with remove_vm_area, !vm on behalf
-        * of vmap area is being tear down or vm_map_ram allocation.
-        */
        if (!va->vm) {
-               seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n",
-                       (void *)va->va_start, (void *)va->va_end,
-                       va->va_end - va->va_start);
+               if (va->flags & VMAP_RAM)
+                       seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n",
+                               (void *)va->va_start, (void *)va->va_end,
+                               va->va_end - va->va_start);
 
                goto final;
        }