mm: Make generic weak get_user_pages_fast and EXPORT_GPL it

Out of line get_user_pages_fast fallback implementation, make it a weak
symbol, get rid of CONFIG_HAVE_GET_USER_PAGES_FAST.

Export the symbol to modules so lguest can use it.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 0 insertions, 20 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 335288bff1b7..fa651609b65d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -834,7 +834,6 @@ extern int mprotect_fixup(struct vm_area_struct *vma,
                           struct vm_area_struct **pprev, unsigned long start,
                           unsigned long end, unsigned long newflags);
 
-#ifdef CONFIG_HAVE_GET_USER_PAGES_FAST
 /*
  * get_user_pages_fast provides equivalent functionality to get_user_pages,
  * operating on current and current->mm (force=0 and doesn't return any vmas).
@@ -848,25 +847,6 @@ extern int mprotect_fixup(struct vm_area_struct *vma,
 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
                         struct page **pages);
 
-#else
-/*
- * Should probably be moved to asm-generic, and architectures can include it if
- * they don't implement their own get_user_pages_fast.
- */
-#define get_user_pages_fast(start, nr_pages, write, pages)      \
-({                                                              \
-        struct mm_struct *mm = current->mm;                     \
-        int ret;                                                \
-                                                                \
-        down_read(&mm->mmap_sem);                               \
-        ret = get_user_pages(current, mm, start, nr_pages,      \
-                                        write, 0, pages, NULL); \
-        up_read(&mm->mmap_sem);                                 \
-                                                                \
-        ret;                                                    \
-})
-#endif
-
 /*
  * A callback you can register to apply pressure to ageable caches.
  *