[PATCH 2/3] z3fold: Remove preempt disabled sections for RT

[Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>]

Replace get_cpu_ptr() with migrate_disable()+this_cpu_ptr()
so RT can take spinlocks that become sleeping locks.

Signed-off-by Mike Galbraith <efault@xxxxxx>
Signed-off-by: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
---
 mm/z3fold.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/mm/z3fold.c b/mm/z3fold.c
index 6c2325cd3fba..9fc1cc9630fe 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -610,14 +610,16 @@ static inline void add_to_unbuddied(struct z3fold_pool *pool,
 {
 	if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 ||
 			zhdr->middle_chunks == 0) {
-		struct list_head *unbuddied = get_cpu_ptr(pool->unbuddied);
-
+		struct list_head *unbuddied;
 		int freechunks = num_free_chunks(zhdr);
+
+		migrate_disable();
+		unbuddied = this_cpu_ptr(pool->unbuddied);
 		spin_lock(&pool->lock);
 		list_add(&zhdr->buddy, &unbuddied[freechunks]);
 		spin_unlock(&pool->lock);
 		zhdr->cpu = smp_processor_id();
-		put_cpu_ptr(pool->unbuddied);
+		migrate_enable();
 	}
 }
 
@@ -854,8 +856,9 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
 	int chunks = size_to_chunks(size), i;
 
 lookup:
+	migrate_disable();
 	/* First, try to find an unbuddied z3fold page. */
-	unbuddied = get_cpu_ptr(pool->unbuddied);
+	unbuddied = this_cpu_ptr(pool->unbuddied);
 	for_each_unbuddied_list(i, chunks) {
 		struct list_head *l = &unbuddied[i];
 
@@ -873,7 +876,7 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
 		    !z3fold_page_trylock(zhdr)) {
 			spin_unlock(&pool->lock);
 			zhdr = NULL;
-			put_cpu_ptr(pool->unbuddied);
+			migrate_enable();
 			if (can_sleep)
 				cond_resched();
 			goto lookup;
@@ -887,7 +890,7 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
 		    test_bit(PAGE_CLAIMED, &page->private)) {
 			z3fold_page_unlock(zhdr);
 			zhdr = NULL;
-			put_cpu_ptr(pool->unbuddied);
+			migrate_enable();
 			if (can_sleep)
 				cond_resched();
 			goto lookup;
@@ -902,7 +905,7 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
 		kref_get(&zhdr->refcount);
 		break;
 	}
-	put_cpu_ptr(pool->unbuddied);
+	migrate_enable();
 
 	if (!zhdr) {
 		int cpu;
-- 
2.20.1