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

Peter Zijlstra
2018-12-03T17:14:48Z

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) <peterz@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;
}