[PATCH 3/4] page-flags: make page flag helpers accept struct head_page

[Kirill A. Shutemov]

This patch makes all generated page flag helpers to accept pointer to
struct head_page as well as struct page.

In case if pointer to struct head_page is passed, we assume that it's
head page and bypass policy constrain checks.

Note, to get get inteface consistent we would need to make non-generated
page flag helper to accept struct head_page as well.

Not-yet-signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 scripts/mkpageflags.sh | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/scripts/mkpageflags.sh b/scripts/mkpageflags.sh
index 29d46bccaea4..272aab4ad1a3 100755
--- a/scripts/mkpageflags.sh
+++ b/scripts/mkpageflags.sh
@@ -6,23 +6,23 @@ fatal() {
 }
 
 any() {
-       echo "(__p)"
+       echo "((struct page *)(__p))"
 }
 
 head() {
-       echo "compound_head(__p)"
+       echo "compound_head((struct page *)(__p))"
 }
 
 no_tail() {
        local enforce="${1:+VM_BUG_ON_PGFLAGS(PageTail(__p), __p);}"
 
-       echo "({$enforce compound_head(__p);})"
+       echo "({$enforce compound_head((struct page *)(__p));})"
 }
 
 no_compound() {
        local enforce="${1:+VM_BUG_ON_PGFLAGS(PageCompound(__p), __p);}"
 
-       echo "({$enforce __p;})"
+       echo "({$enforce ((struct page *)(__p));})"
 }
 
 generate_test() {
@@ -34,7 +34,9 @@ generate_test() {
        cat <<EOF
 #define $uname(__p) ({                                                         
\\
        int ret;                                                                
\\
-       if (__builtin_types_compatible_p(typeof(*(__p)), struct page))          
\\
+       if (__builtin_types_compatible_p(typeof(*(__p)), struct head_page))     
\\
+               ret = $op(PG_$lname, &((struct head_page *)(__p))->page.flags); 
\\
+       else if (__builtin_types_compatible_p(typeof(*(__p)), struct page))     
\\
                ret = $op(PG_$lname, &$page->flags);                            
\\
        else                                                                    
\\
                BUILD_BUG();                                                    
\\
@@ -52,7 +54,9 @@ generate_mod() {
 
        cat <<EOF
 #define $uname(__p) do {                                                       
\\
-       if (__builtin_types_compatible_p(typeof(*(__p)), struct page))          
\\
+       if (__builtin_types_compatible_p(typeof(*(__p)), struct head_page))     
\\
+               $op(PG_$lname, &((struct head_page *)(__p))->page.flags);       
\\
+       else if (__builtin_types_compatible_p(typeof(*(__p)), struct page))     
\\
                $op(PG_$lname, &$page->flags);                                  
\\
        else                                                                    
\\
                BUILD_BUG();                                                    
\\
-- 
2.8.0.rc3