From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932348AbWHaVgT (ORCPT ); Thu, 31 Aug 2006 17:36:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932358AbWHaVgS (ORCPT ); Thu, 31 Aug 2006 17:36:18 -0400 Received: from mx1.redhat.com ([66.187.233.31]:2748 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S932338AbWHaVfz (ORCPT ); Thu, 31 Aug 2006 17:35:55 -0400 From: David Howells Subject: [PATCH 2/4] NOMMU: Order the per-mm_struct VMA list Date: Thu, 31 Aug 2006 22:35:35 +0100 To: torvalds@osdl.org, akpm@osdl.org Cc: linux-kernel@vger.kernel.org, uclinux-dev@uclinux.org, dhowells@redhat.com Message-Id: <20060831213535.29363.10894.stgit@warthog.cambridge.redhat.com> In-Reply-To: <20060831213530.29363.6372.stgit@warthog.cambridge.redhat.com> References: <20060831213530.29363.6372.stgit@warthog.cambridge.redhat.com> Content-Type: text/plain; charset=utf-8; format=fixed Content-Transfer-Encoding: 8bit User-Agent: StGIT/0.10 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: David Howells Order the per-mm_struct VMA list by address so that searching it can be cut short when the appropriate address has been exceeded. Signed-Off-By: David Howells --- mm/nommu.c | 105 ++++++++++++++++++++++++++++++++++++++++++------------------ 1 files changed, 73 insertions(+), 32 deletions(-) diff --git a/mm/nommu.c b/mm/nommu.c index 9d57c2a..20da741 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -286,6 +286,49 @@ static void show_process_blocks(void) } #endif /* DEBUG */ +/* + * add a VMA into a process's mm_struct in the appropriate place in the list + * - should be called with mm->mmap_sem held writelocked + */ +static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml) +{ + struct vm_list_struct **ppv; + + for (ppv = ¤t->mm->context.vmlist; *ppv; ppv = &(*ppv)->next) + if ((*ppv)->vma->vm_start > vml->vma->vm_start) + break; + + vml->next = *ppv; + *ppv = vml; +} + +/* + * look up the first VMA in which addr resides, NULL if none + * - should be called with mm->mmap_sem at least held readlocked + */ +struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) +{ + struct vm_list_struct *loop, *vml; + + /* search the vm_start ordered list */ + vml = NULL; + for (loop = mm->context.vmlist; loop; loop = loop->next) { + if (loop->vma->vm_start > addr) + break; + vml = loop; + } + + if (vml && vml->vma->vm_end > addr) + return vml->vma; + + return NULL; +} + +EXPORT_SYMBOL(find_vma); + +/* + * find a VMA in the global tree + */ static inline struct vm_area_struct *find_nommu_vma(unsigned long start) { struct vm_area_struct *vma; @@ -305,6 +348,9 @@ static inline struct vm_area_struct *fin return NULL; } +/* + * add a VMA in the global tree + */ static void add_nommu_vma(struct vm_area_struct *vma) { struct vm_area_struct *pvma; @@ -351,6 +397,9 @@ static void add_nommu_vma(struct vm_area rb_insert_color(&vma->vm_rb, &nommu_vma_tree); } +/* + * delete a VMA from the global list + */ static void delete_nommu_vma(struct vm_area_struct *vma) { struct address_space *mapping; @@ -828,8 +877,7 @@ unsigned long do_mmap_pgoff(struct file realalloc += kobjsize(vml); askedalloc += sizeof(*vml); - vml->next = current->mm->context.vmlist; - current->mm->context.vmlist = vml; + add_vma_to_mm(current->mm, vml); up_write(&nommu_vma_sem); @@ -908,6 +956,11 @@ static void put_vma(struct vm_area_struc } } +/* + * release a mapping + * - under NOMMU conditions the parameters must match exactly to the mapping to + * be removed + */ int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len) { struct vm_list_struct *vml, **parent; @@ -917,10 +970,13 @@ #ifdef DEBUG printk("do_munmap:\n"); #endif - for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) + for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) { + if ((*parent)->vma->vm_start > addr) + break; if ((*parent)->vma->vm_start == addr && ((len == 0) || ((*parent)->vma->vm_end == end))) goto found; + } printk("munmap of non-mmaped memory by process %d (%s): %p\n", current->pid, current->comm, (void *) addr); @@ -946,7 +1002,20 @@ #endif return 0; } -/* Release all mmaps. */ +asmlinkage long sys_munmap(unsigned long addr, size_t len) +{ + int ret; + struct mm_struct *mm = current->mm; + + down_write(&mm->mmap_sem); + ret = do_munmap(mm, addr, len); + up_write(&mm->mmap_sem); + return ret; +} + +/* + * Release all mappings + */ void exit_mmap(struct mm_struct * mm) { struct vm_list_struct *tmp; @@ -973,17 +1042,6 @@ #endif } } -asmlinkage long sys_munmap(unsigned long addr, size_t len) -{ - int ret; - struct mm_struct *mm = current->mm; - - down_write(&mm->mmap_sem); - ret = do_munmap(mm, addr, len); - up_write(&mm->mmap_sem); - return ret; -} - unsigned long do_brk(unsigned long addr, unsigned long len) { return -ENOMEM; @@ -1037,23 +1095,6 @@ unsigned long do_mremap(unsigned long ad return vml->vma->vm_start; } -/* - * Look up the first VMA which satisfies addr < vm_end, NULL if none - * - should be called with mm->mmap_sem at least readlocked - */ -struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) -{ - struct vm_list_struct *vml; - - for (vml = mm->context.vmlist; vml; vml = vml->next) - if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end) - return vml->vma; - - return NULL; -} - -EXPORT_SYMBOL(find_vma); - struct page *follow_page(struct vm_area_struct *vma, unsigned long address, unsigned int foll_flags) {