The patch titled
Subject: mm, vmalloc: protect va->vm by vmap_area_lock
has been added to the -mm tree. Its filename is
mm-vmalloc-protect-va-vm-by-vmap_area_lock.patch
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------------------------------------------------------
From: Joonsoo Kim <js1304@xxxxxxxxx>
Subject: mm, vmalloc: protect va->vm by vmap_area_lock
Inserting and removing an entry to vmlist is linear time complexity, so it
is inefficient. Following patches will try to remove vmlist entirely.
This patch is preparing step for it.
For removing vmlist, iterating vmlist codes should be changed to iterating
a vmap_area_list. Before implementing that, we should make sure that when
we iterate a vmap_area_list, accessing to va->vm doesn't cause a race
condition. This patch ensure that when iterating a vmap_area_list, there
is no race condition for accessing to vm_struct.
Signed-off-by: Joonsoo Kim <js1304@xxxxxxxxx>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Atsushi Kumagai <kumagai-atsushi@xxxxxxxxxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Dave Anderson <anderson@xxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Guan Xuetao <gxt@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 7 +++++++
1 file changed, 7 insertions(+)
diff -puN mm/vmalloc.c~mm-vmalloc-protect-va-vm-by-vmap_area_lock mm/vmalloc.c
--- a/mm/vmalloc.c~mm-vmalloc-protect-va-vm-by-vmap_area_lock
+++ a/mm/vmalloc.c
@@ -1290,12 +1290,14 @@ struct vm_struct *vmlist;
static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
unsigned long flags, const void *caller)
{
+ spin_lock(&vmap_area_lock);
vm->flags = flags;
vm->addr = (void *)va->va_start;
vm->size = va->va_end - va->va_start;
vm->caller = caller;
va->vm = vm;
va->flags |= VM_VM_AREA;
+ spin_unlock(&vmap_area_lock);
}
static void insert_vmalloc_vmlist(struct vm_struct *vm)
@@ -1447,6 +1449,11 @@ struct vm_struct *remove_vm_area(const v
if (va && va->flags & VM_VM_AREA) {
struct vm_struct *vm = va->vm;
+ spin_lock(&vmap_area_lock);
+ va->vm = NULL;
+ va->flags &= ~VM_VM_AREA;
+ spin_unlock(&vmap_area_lock);
+
if (!(vm->flags & VM_UNLIST)) {
struct vm_struct *tmp, **p;
/*
_
Patches currently in -mm which might be from js1304@xxxxxxxxx are
linux-next.patch
mm-vmalloc-change-iterating-a-vmlist-to-find_vm_area.patch
mm-vmalloc-move-get_vmalloc_info-to-vmallocc.patch
mm-vmalloc-protect-va-vm-by-vmap_area_lock.patch
mm-vmalloc-iterate-vmap_area_list-instead-of-vmlist-in-vread-vwrite.patch
mm-vmalloc-iterate-vmap_area_list-in-get_vmalloc_info.patch
mm-vmalloc-iterate-vmap_area_list-instead-of-vmlist-in-vmallocinfo.patch
mm-vmalloc-export-vmap_area_list-instead-of-vmlist.patch
mm-vmalloc-remove-list-management-of-vmlist-after-initializing-vmalloc.patch
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