Revert "futex: Restore one of the fast paths eliminated by 38d47c1b7075bd7ec3881141bb...

This reverts commit 8d4c42afa543eda97ce1bc88f160ac1e0379ec52.

diff --git a/kernel/futex.c b/kernel/futex.c
index 546e13300d3b9317609f88fa647d949fd6885dfb..fb65e822fc41ae698c282aeadc6933b411aa8a78 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -222,7 +222,6 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
        struct mm_struct *mm = current->mm;
        struct page *page;
        int err;
-       struct vm_area_struct *vma;
 
        /*
         * The futex address must be "naturally" aligned.
@@ -248,37 +247,6 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
                return 0;
        }
 
-       /*
-        * The futex is hashed differently depending on whether
-        * it's in a shared or private mapping.  So check vma first.
-        */
-       vma = find_extend_vma(mm, address);
-       if (unlikely(!vma))
-               return -EFAULT;
-
-       /*
-        * Permissions.
-        */
-       if (unlikely((vma->vm_flags & (VM_IO|VM_READ)) != VM_READ))
-               return (vma->vm_flags & VM_IO) ? -EPERM : -EACCES;
-
-       /*
-        * Private mappings are handled in a simple way.
-        *
-        * NOTE: When userspace waits on a MAP_SHARED mapping, even if
-        * it's a read-only handle, it's expected that futexes attach to
-        * the object not the particular process.  Therefore we use
-        * VM_MAYSHARE here, not VM_SHARED which is restricted to shared
-        * mappings of _writable_ handles.
-        */
-       if (likely(!(vma->vm_flags & VM_MAYSHARE))) {
-               key->both.offset |= FUT_OFF_MMSHARED; /* reference taken on mm */
-               key->private.mm = mm;
-               key->private.address = address;
-               get_futex_key_refs(key);
-               return 0;
-       }
-
 again:
        err = get_user_pages_fast(address, 1, rw == VERIFY_WRITE, &page);
        if (err < 0)