1 files changed, 14 insertions, 49 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index 8a310e240cda..eed92a8a4c49 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -469,7 +469,8 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
 {
         unsigned long address = (unsigned long)uaddr;
         struct mm_struct *mm = current->mm;
-        struct page *page, *page_head;
+        struct page *page;
+        struct address_space *mapping;
         int err, ro = 0;
 
         /*
@@ -519,46 +520,9 @@ again:
         else
                 err = 0;
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-        page_head = page;
-        if (unlikely(PageTail(page))) {
-                put_page(page);
-                /* serialize against __split_huge_page_splitting() */
-                local_irq_disable();
-                if (likely(__get_user_pages_fast(address, 1, !ro, &page) == 1)) {
-                        page_head = compound_head(page);
-                        /*
-                         * page_head is valid pointer but we must pin
-                         * it before taking the PG_lock and/or
-                         * PG_compound_lock. The moment we re-enable
-                         * irqs __split_huge_page_splitting() can
-                         * return and the head page can be freed from
-                         * under us. We can't take the PG_lock and/or
-                         * PG_compound_lock on a page that could be
-                         * freed from under us.
-                         */
-                        if (page != page_head) {
-                                get_page(page_head);
-                                put_page(page);
-                        }
-                        local_irq_enable();
-                } else {
-                        local_irq_enable();
-                        goto again;
-                }
-        }
-#else
-        page_head = compound_head(page);
-        if (page != page_head) {
-                get_page(page_head);
-                put_page(page);
-        }
-#endif
-
-        lock_page(page_head);
-
+        lock_page(page);
         /*
-         * If page_head->mapping is NULL, then it cannot be a PageAnon
+         * If page->mapping is NULL, then it cannot be a PageAnon
          * page; but it might be the ZERO_PAGE or in the gate area or
          * in a special mapping (all cases which we are happy to fail);
          * or it may have been a good file page when get_user_pages_fast
@@ -570,12 +534,13 @@ again:
          *
          * The case we do have to guard against is when memory pressure made
          * shmem_writepage move it from filecache to swapcache beneath us:
-         * an unlikely race, but we do need to retry for page_head->mapping.
+         * an unlikely race, but we do need to retry for page->mapping.
          */
-        if (!page_head->mapping) {
-                int shmem_swizzled = PageSwapCache(page_head);
-                unlock_page(page_head);
-                put_page(page_head);
+        mapping = compound_head(page)->mapping;
+        if (!mapping) {
+                int shmem_swizzled = PageSwapCache(page);
+                unlock_page(page);
+                put_page(page);
                 if (shmem_swizzled)
                         goto again;
                 return -EFAULT;
@@ -588,7 +553,7 @@ again:
          * it's a read-only handle, it's expected that futexes attach to
          * the object not the particular process.
          */
-        if (PageAnon(page_head)) {
+        if (PageAnon(page)) {
                 /*
                  * A RO anonymous page will never change and thus doesn't make
                  * sense for futex operations.
@@ -603,15 +568,15 @@ again:
                 key->private.address = address;
         } else {
                 key->both.offset |= FUT_OFF_INODE; /* inode-based key */
-                key->shared.inode = page_head->mapping->host;
+                key->shared.inode = mapping->host;
                 key->shared.pgoff = basepage_index(page);
         }
 
         get_futex_key_refs(key); /* implies MB (B) */
 
 out:
-        unlock_page(page_head);
-        put_page(page_head);
+        unlock_page(page);
+        put_page(page);
         return err;
 }