[PATCH v4 15/20] powerpc/mm: Avoid useless lock with single page fragments

[Christophe Leroy]

There is no point in taking the page table lock as
pte_frag is always NULL when we have only one fragment.

Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
---
 arch/powerpc/mm/pgtable-frag.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
index bc924822dcd6..ab4910e92aaf 100644
--- a/arch/powerpc/mm/pgtable-frag.c
+++ b/arch/powerpc/mm/pgtable-frag.c
@@ -85,6 +85,9 @@ static pte_t *get_pte_from_cache(struct mm_struct *mm)
 {
 	void *pte_frag, *ret;
 
+	if (PTE_FRAG_NR == 1)
+		return NULL;
+
 	spin_lock(&mm->page_table_lock);
 	ret = mm->context.pte_frag;
 	if (ret) {
-- 
2.13.3