From 869176a096068056b338b5cc1b0af93106007f5d Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Mon, 6 Feb 2023 16:40:15 +0800 Subject: mm/vmalloc.c: add flags to mark vm_map_ram area Through vmalloc API, a virtual kernel area is reserved for physical address mapping. And vmap_area is used to track them, while vm_struct is allocated to associate with the vmap_area to store more information and passed out. However, area reserved via vm_map_ram() is an exception. It doesn't have vm_struct to associate with vmap_area. And we can't recognize the vmap_area with '->vm == NULL' as a vm_map_ram() area because the normal freeing path will set va->vm = NULL before unmapping, please see function remove_vm_area(). Meanwhile, there are two kinds of handling for vm_map_ram area. One is the whole vmap_area being reserved and mapped at one time through vm_map_area() interface; the other is the whole vmap_area with VMAP_BLOCK_SIZE size being reserved, while mapped into split regions with smaller size via vb_alloc(). To mark the area reserved through vm_map_ram(), add flags field into struct vmap_area. Bit 0 indicates this is vm_map_ram area created through vm_map_ram() interface, while bit 1 marks out the type of vm_map_ram area which makes use of vmap_block to manage split regions via vb_alloc/free(). This is a preparation for later use. Link: https://lkml.kernel.org/r/20230206084020.174506-3-bhe@redhat.com Signed-off-by: Baoquan He Reviewed-by: Lorenzo Stoakes Reviewed-by: Uladzislau Rezki (Sony) Cc: Dan Carpenter Cc: Stephen Brennan Signed-off-by: Andrew Morton --- include/linux/vmalloc.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/vmalloc.h') diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 096d48aa3437..69250efa03d1 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -76,6 +76,7 @@ struct vmap_area { unsigned long subtree_max_size; /* in "free" tree */ struct vm_struct *vm; /* in "busy" tree */ }; + unsigned long flags; /* mark type of vm_map_ram area */ }; /* archs that select HAVE_ARCH_HUGE_VMAP should override one or more of these */ -- cgit v1.2.3