[PATCH 2/4] x86: simplify cpa_process_alias()

Tejun Heo
2009-05-14T12:51:31Z

The two existing alias conditions in cpa_process_alias() are mutually
exclusive and future ones are likely to be exclusive too. Simplify
control flow to ease adding other alias cases.

The within(vaddr, (unsigned long)_text, _brk_end) test is removed as
it's guaranteed to be false if vaddr is in the page mapped area.

[ Impact: cleanup, no functional difference ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
---
arch/x86/mm/pageattr.c | 42 ++++++++++++++++++------------------------
1 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 797f9f1..1097b61 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -686,7 +686,6 @@ static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias);
static int cpa_process_alias(struct cpa_data *cpa)
{
struct cpa_data alias_cpa;
- int ret = 0;
unsigned long temp_cpa_vaddr, vaddr;

if (cpa->pfn >= max_pfn_mapped)
@@ -715,38 +714,33 @@ static int cpa_process_alias(struct cpa_data *cpa)
alias_cpa.vaddr = &temp_cpa_vaddr;
alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);

-
- ret = __change_page_attr_set_clr(&alias_cpa, 0);
+ return __change_page_attr_set_clr(&alias_cpa, 0);
}

-#ifdef CONFIG_X86_64
- if (ret)
- return ret;
- /*
- * No need to redo, when the primary call touched the high
- * mapping already:
- */
- if (within(vaddr, (unsigned long) _text, _brk_end))
- return 0;
+ /* vaddr is in page mapped area */

+#ifdef CONFIG_X86_64
/*
* If the physical address is inside the kernel map, we need
* to touch the high mapped kernel as well:
*/
- if (!within(cpa->pfn, highmap_start_pfn(), highmap_end_pfn()))
- return 0;
-
- alias_cpa = *cpa;
- temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) + __START_KERNEL_map - phys_base;
- alias_cpa.vaddr = &temp_cpa_vaddr;
- alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);
+ if (within(cpa->pfn, highmap_start_pfn(), highmap_end_pfn())) {
+ alias_cpa = *cpa;
+ temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) +
+ __START_KERNEL_map - phys_base;
+ alias_cpa.vaddr = &temp_cpa_vaddr;
+ alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);

- /*
- * The high mapping range is imprecise, so ignore the return value.
- */
- __change_page_attr_set_clr(&alias_cpa, 0);
+ /*
+ * The high mapping range is imprecise, so ignore the
+ * return value.
+ */
+ __change_page_attr_set_clr(&alias_cpa, 0);
+ return 0;
+ }
#endif
- return ret;
+
+ return 0;
}

static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias)
--
1.6.0.2