From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx129.postini.com [74.125.245.129]) by kanga.kvack.org (Postfix) with SMTP id 24DB46B0039 for ; Wed, 13 Mar 2013 02:33:11 -0400 (EDT) From: Joonsoo Kim Subject: [PATCH v2 3/8] mm, vmalloc: protect va->vm by vmap_area_lock Date: Wed, 13 Mar 2013 15:32:55 +0900 Message-Id: <1363156381-2881-4-git-send-email-iamjoonsoo.kim@lge.com> In-Reply-To: <1363156381-2881-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1363156381-2881-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Anderson , Atsushi Kumagai , Vivek Goyal , Bob Liu , Pekka Enberg , kexec@lists.infradead.org, Joonsoo Kim , Joonsoo Kim From: Joonsoo Kim 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 Signed-off-by: Joonsoo Kim diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 1d9878b..1bf94ad 100644 --- a/mm/vmalloc.c +++ b/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 void *addr) 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; /* -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org