[RFC][PATCH 04/10] x86/mm/cpa: Make cpa_data::vaddr invariant

[Peter Zijlstra]

Currently __change_page_attr_set_clr() will modify cpa->vaddr when
!(CPA_ARRAY | CPA_PAGES_ARRAY), whereas in the array cases it will
increment cpa->curpage.

Change __cpa_addr() such that its @idx argument also works in the
!array case and use cpa->curpage increments for all cases.

NOTE: since cpa_data::numpages is 'unsigned long' so should cpa_data::curpage 
be.
NOTE: after this only cpa->numpages is still modified.

Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
 arch/x86/mm/pageattr.c |   18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -35,11 +35,11 @@ struct cpa_data {
        pgprot_t        mask_set;
        pgprot_t        mask_clr;
        unsigned long   numpages;
-       int             flags;
+       unsigned long   curpage;
        unsigned long   pfn;
-       unsigned        force_split             : 1,
+       unsigned int    flags;
+       unsigned int    force_split             : 1,
                        force_static_prot       : 1;
-       int             curpage;
        struct page     **pages;
 };
 
@@ -228,7 +228,7 @@ static bool __cpa_pfn_in_highmap(unsigne
 
 #endif
 
-static unsigned long __cpa_addr(struct cpa_data *cpa, int idx)
+static unsigned long __cpa_addr(struct cpa_data *cpa, unsigned long idx)
 {
        if (cpa->flags & CPA_PAGES_ARRAY) {
                struct page *page = cpa->pages[idx];
@@ -242,7 +242,7 @@ static unsigned long __cpa_addr(struct c
        if (cpa->flags & CPA_ARRAY)
                return cpa->vaddr[idx];
 
-       return *cpa->vaddr;
+       return *cpa->vaddr + idx * PAGE_SIZE;
 }
 
 /*
@@ -1581,6 +1581,7 @@ static int cpa_process_alias(struct cpa_
                alias_cpa = *cpa;
                alias_cpa.vaddr = &laddr;
                alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);
+               alias_cpa.curpage = 0;
 
                ret = __change_page_attr_set_clr(&alias_cpa, 0);
                if (ret)
@@ -1600,6 +1601,7 @@ static int cpa_process_alias(struct cpa_
                alias_cpa = *cpa;
                alias_cpa.vaddr = &temp_cpa_vaddr;
                alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);
+               alias_cpa.curpage = 0;
 
                /*
                 * The high mapping range is imprecise, so ignore the
@@ -1648,11 +1650,7 @@ static int __change_page_attr_set_clr(st
                 */
                BUG_ON(cpa->numpages > numpages || !cpa->numpages);
                numpages -= cpa->numpages;
-               if (cpa->flags & (CPA_PAGES_ARRAY | CPA_ARRAY))
-                       cpa->curpage++;
-               else
-                       *cpa->vaddr += cpa->numpages * PAGE_SIZE;
-
+               cpa->curpage += cpa->numpages;
        }
        return 0;
 }