(textually depends on procfs-task-exe-symlink.patch)
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 <[EMAIL PROTECTED]>
--- 25/mm/mmap.c~1_MMAP 2008-02-15 17:48:48.000000000 +0300
+++ 25/mm/mmap.c 2008-02-15 18:23:26.000000000 +0300
@@ -1070,7 +1070,6 @@ int vma_wants_writenotify(struct vm_area
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,
@@ -1185,24 +1184,22 @@ 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);
- if (vm_flags & VM_EXECUTABLE)
- removed_exe_file_vma(mm);
- }
mpol_free(vma_policy(vma));
kmem_cache_free(vm_area_cachep, vma);
+ fput(file);
+ if (vm_flags & VM_EXECUTABLE)
+ removed_exe_file_vma(mm);
+ } 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) {
--
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