block: uapi: fix comment about block device ioctl

[linux-2.6-microblaze.git] / include / linux / hugetlb.h

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index e97498a..cccd1aa 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -139,7 +139,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
                                unsigned long dst_addr,
                                unsigned long src_addr,
                                struct page **pagep);
-int hugetlb_reserve_pages(struct inode *inode, long from, long to,
+bool hugetlb_reserve_pages(struct inode *inode, long from, long to,
                                                struct vm_area_struct *vma,
                                                vm_flags_t vm_flags);
 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
@@ -480,18 +480,30 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  * HPG_restore_reserve - Set when a hugetlb page consumes a reservation at
  *     allocation time.  Cleared when page is fully instantiated.  Free
  *     routine checks flag to restore a reservation on error paths.
+ *     Synchronization:  Examined or modified by code that knows it has
+ *     the only reference to page.  i.e. After allocation but before use
+ *     or when the page is being freed.
  * HPG_migratable  - Set after a newly allocated page is added to the page
  *     cache and/or page tables.  Indicates the page is a candidate for
  *     migration.
+ *     Synchronization:  Initially set after new page allocation with no
+ *     locking.  When examined and modified during migration processing
+ *     (isolate, migrate, putback) the hugetlb_lock is held.
  * HPG_temporary - - Set on a page that is temporarily allocated from the buddy
  *     allocator.  Typically used for migration target pages when no pages
  *     are available in the pool.  The hugetlb free page path will
  *     immediately free pages with this flag set to the buddy allocator.
+ *     Synchronization: Can be set after huge page allocation from buddy when
+ *     code knows it has only reference.  All other examinations and
+ *     modifications require hugetlb_lock.
+ * HPG_freed - Set when page is on the free lists.
+ *     Synchronization: hugetlb_lock held for examination and modification.
  */
 enum hugetlb_page_flags {
        HPG_restore_reserve = 0,
        HPG_migratable,
        HPG_temporary,
+       HPG_freed,
        __NR_HPAGEFLAGS,
 };
 
@@ -536,6 +548,7 @@ static inline void ClearHPage##uname(struct page *page)             \
 HPAGEFLAG(RestoreReserve, restore_reserve)
 HPAGEFLAG(Migratable, migratable)
 HPAGEFLAG(Temporary, temporary)
+HPAGEFLAG(Freed, freed)
 
 #ifdef CONFIG_HUGETLB_PAGE