ALSA: pcm: potential uninitialized return values

[pandora-kernel.git] / mm / internal.h

diff --git a/mm/internal.h b/mm/internal.h
index d071d38..0c26b5e 100644 (file)
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -37,6 +37,52 @@ static inline void __put_page(struct page *page)
        atomic_dec(&page->_count);
 }
 
+static inline void __get_page_tail_foll(struct page *page,
+                                       bool get_page_head)
+{
+       /*
+        * If we're getting a tail page, the elevated page->_count is
+        * required only in the head page and we will elevate the head
+        * page->_count and tail page->_mapcount.
+        *
+        * We elevate page_tail->_mapcount for tail pages to force
+        * page_tail->_count to be zero at all times to avoid getting
+        * false positives from get_page_unless_zero() with
+        * speculative page access (like in
+        * page_cache_get_speculative()) on tail pages.
+        */
+       VM_BUG_ON(atomic_read(&page->first_page->_count) <= 0);
+       VM_BUG_ON(atomic_read(&page->_count) != 0);
+       VM_BUG_ON(page_mapcount(page) < 0);
+       if (get_page_head)
+               atomic_inc(&page->first_page->_count);
+       atomic_inc(&page->_mapcount);
+}
+
+/*
+ * This is meant to be called as the FOLL_GET operation of
+ * follow_page() and it must be called while holding the proper PT
+ * lock while the pte (or pmd_trans_huge) is still mapping the page.
+ */
+static inline void get_page_foll(struct page *page)
+{
+       if (unlikely(PageTail(page)))
+               /*
+                * This is safe only because
+                * __split_huge_page_refcount() can't run under
+                * get_page_foll() because we hold the proper PT lock.
+                */
+               __get_page_tail_foll(page, true);
+       else {
+               /*
+                * Getting a normal page or the head of a compound page
+                * requires to already have an elevated page->_count.
+                */
+               VM_BUG_ON(atomic_read(&page->_count) <= 0);
+               atomic_inc(&page->_count);
+       }
+}
+
 extern unsigned long highest_memmap_pfn;
 
 /*
@@ -263,3 +309,5 @@ extern u64 hwpoison_filter_flags_mask;
 extern u64 hwpoison_filter_flags_value;
 extern u64 hwpoison_filter_memcg;
 extern u32 hwpoison_filter_enable;
+
+extern void set_pageblock_order(void);