- add BUG statement to catch invalid start and end parameters
- No need to track the actual type in both req_type and actual_type --
keep req_type unchanged.
- removed (IMHO) superfluous comments
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
---
arch/x86/mm/pat.c | 21 ++++++++-------------
1 files changed, 8 insertions(+), 13 deletions(-)
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index a6507bf..c996a36 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -200,7 +200,8 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
unsigned long actual_type;
int err = 0;
- /* Only track when pat_enabled */
+ BUG_ON(start >= end); /* end is exclusive */
+
if (!pat_enabled) {
/* This is identical to page table setting without PAT */
if (new_type) {
@@ -228,17 +229,13 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
*/
u8 mtrr_type = mtrr_type_lookup(start, end);
- if (mtrr_type == MTRR_TYPE_WRBACK) {
- req_type = _PAGE_CACHE_WB;
+ if (mtrr_type == MTRR_TYPE_WRBACK)
actual_type = _PAGE_CACHE_WB;
- } else {
- req_type = _PAGE_CACHE_UC_MINUS;
+ else
actual_type = _PAGE_CACHE_UC_MINUS;
- }
- } else {
- req_type &= _PAGE_CACHE_MASK;
- actual_type = pat_x_mtrr_type(start, end, req_type);
- }
+ } else
+ actual_type = pat_x_mtrr_type(start, end,
+ req_type & _PAGE_CACHE_MASK);
new = kmalloc(sizeof(struct memtype), GFP_KERNEL);
if (!new)
@@ -406,10 +403,8 @@ int free_memtype(u64 start, u64 end)
struct memtype *entry;
int err = -EINVAL;
- /* Only track when pat_enabled */
- if (!pat_enabled) {
+ if (!pat_enabled)
return 0;
- }
/* Low ISA region is always mapped WB. No need to track */
if (is_ISA_range(start, end - 1))
--
1.5.5.4
--
