From 4d3d5b41a72b52555d43efbfc4ccde6ba6e5444f Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 28 Apr 2008 02:12:10 -0700 Subject: [PATCH] mmap_region: cleanup the final vma_merge() related code It is not easy to actually understand the "if (!file || !vma_merge())" code, turn it into "if (file && vma_merge())". This makes immediately obvious that the subsequent "if (file)" is superfluous. As Hugh Dickins pointed out, we can also factor out the ->i_writecount corrections, and add a small comment about that. Signed-off-by: Oleg Nesterov Cc: Miklos Szeredi Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index a32d28ce31c..6aaf657adb8 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1068,7 +1068,6 @@ int vma_wants_writenotify(struct vm_area_struct *vma) mapping_cap_account_dirty(vma->vm_file->f_mapping); } - unsigned long mmap_region(struct file *file, unsigned long addr, unsigned long len, unsigned long flags, unsigned int vm_flags, unsigned long pgoff, @@ -1181,22 +1180,20 @@ munmap_back: if (vma_wants_writenotify(vma)) vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); - if (!file || !vma_merge(mm, prev, addr, vma->vm_end, + if (file && vma_merge(mm, prev, addr, vma->vm_end, vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) { - file = vma->vm_file; - vma_link(mm, vma, prev, rb_link, rb_parent); - if (correct_wcount) - atomic_inc(&inode->i_writecount); - } else { - if (file) { - if (correct_wcount) - atomic_inc(&inode->i_writecount); - fput(file); - } mpol_free(vma_policy(vma)); kmem_cache_free(vm_area_cachep, vma); + fput(file); + } else { + vma_link(mm, vma, prev, rb_link, rb_parent); + file = vma->vm_file; } -out: + + /* Once vma denies write, undo our temporary denial count */ + if (correct_wcount) + atomic_inc(&inode->i_writecount); +out: mm->total_vm += len >> PAGE_SHIFT; vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); if (vm_flags & VM_LOCKED) { -- 2.20.1