[PATCH v2] x86/mm: fix "old_pte" set but not used

From: Qian Cai
Date: Fri Mar 01 2019 - 10:29:48 EST


The commit 3a19109efbfa ("x86/mm: Fix try_preserve_large_page() to
handle large PAT bit") fixed try_preserve_large_page() by using the
corresponding pud/pmd prot/pfn interfaces, but left a variable unused
because it no longer used pte_pfn().

Later, the commit 8679de0959e6 ("x86/mm/cpa: Split, rename and clean up
try_preserve_large_page()") renamed try_preserve_large_page() to
__should_split_large_page(), but the unused variable remains.

arch/x86/mm/pageattr.c: In function '__should_split_large_page':
arch/x86/mm/pageattr.c:741:17: warning: variable 'old_pte' set but not
used [-Wunused-but-set-variable]

Signed-off-by: Qian Cai <cai@xxxxxx>
---

v2: improve the commit message.

arch/x86/mm/pageattr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 14e6119838a6..4c570612e24e 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -738,7 +738,7 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
{
unsigned long numpages, pmask, psize, lpaddr, pfn, old_pfn;
pgprot_t old_prot, new_prot, req_prot, chk_prot;
- pte_t new_pte, old_pte, *tmp;
+ pte_t new_pte, *tmp;
enum pg_level level;

/*
@@ -781,7 +781,7 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
* Convert protection attributes to 4k-format, as cpa->mask* are set
* up accordingly.
*/
- old_pte = *kpte;
+
/* Clear PSE (aka _PAGE_PAT) and move PAT bit to correct position */
req_prot = pgprot_large_2_4k(old_prot);

--
2.17.2 (Apple Git-113)