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| author | Oleg Nesterov <oleg@redhat.com> | 2013-09-11 14:20:20 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-11 15:57:07 -0700 |
| commit | e86867720e617774b560dfbc169b7f3d0d490950 (patch) | |
| tree | b28f617ed448da3906131b9a67def196e0ce76c4 /mm/mmap.c | |
| parent | 077bf22b5cf233863826afbfa4af9b18650a832d (diff) | |
| download | linux-e86867720e617774b560dfbc169b7f3d0d490950.tar.gz linux-e86867720e617774b560dfbc169b7f3d0d490950.tar.bz2 linux-e86867720e617774b560dfbc169b7f3d0d490950.zip | |
mm: mmap_region: kill correct_wcount/inode, use allow_write_access()
correct_wcount and inode in mmap_region() just complicate the code. This
boolean was needed previously, when deny_write_access() was called before
vma_merge(), now we can simply check VM_DENYWRITE and do
allow_write_access() if it is set.
allow_write_access() checks file != NULL, so this is safe even if it was
possible to use VM_DENYWRITE && !file. Just we need to ensure we use the
same file which was deny_write_access()'ed, so the patch also moves "file
= vma->vm_file" down after allow_write_access().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Colin Cross <ccross@android.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 14 |
1 files changed, 5 insertions, 9 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 1e7a3ea23f1a..13926a5a6901 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1479,11 +1479,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr, { struct mm_struct *mm = current->mm; struct vm_area_struct *vma, *prev; - int correct_wcount = 0; int error; struct rb_node **rb_link, *rb_parent; unsigned long charged = 0; - struct inode *inode = file ? file_inode(file) : NULL; /* Check against address space limit. */ if (!may_expand_vm(mm, len >> PAGE_SHIFT)) { @@ -1552,7 +1550,6 @@ munmap_back: error = deny_write_access(file); if (error) goto free_vma; - correct_wcount = 1; } vma->vm_file = get_file(file); error = file->f_op->mmap(file, vma); @@ -1593,11 +1590,10 @@ munmap_back: } vma_link(mm, vma, prev, rb_link, rb_parent); - file = vma->vm_file; - /* Once vma denies write, undo our temporary denial count */ - if (correct_wcount) - atomic_inc(&inode->i_writecount); + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); + file = vma->vm_file; out: perf_event_mmap(vma); @@ -1616,8 +1612,8 @@ out: return addr; unmap_and_free_vma: - if (correct_wcount) - atomic_inc(&inode->i_writecount); + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); vma->vm_file = NULL; fput(file); |