1 files changed, 51 insertions, 28 deletions

diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
index 57575c7f5635..e049d00c087a 100644
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -39,7 +39,7 @@
 #define debugln(x, ...)         ((void)0)
 
 #define dbg_might_sleep()       ((void)0)
-#define DBG_BUGON(...)          ((void)0)
+#define DBG_BUGON(x)            ((void)(x))
 #endif
 
 enum {
@@ -194,50 +194,70 @@ struct erofs_workgroup {
 
 #define EROFS_LOCKED_MAGIC     (INT_MIN | 0xE0F510CCL)
 
-static inline bool erofs_workgroup_try_to_freeze(
-	struct erofs_workgroup *grp, int v)
+#if defined(CONFIG_SMP)
+static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
+						 int val)
 {
-#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
-	if (v != atomic_cmpxchg(&grp->refcount,
-		v, EROFS_LOCKED_MAGIC))
-		return false;
 	preempt_disable();
+	if (val != atomic_cmpxchg(&grp->refcount, val, EROFS_LOCKED_MAGIC)) {
+		preempt_enable();
+		return false;
+	}
+	return true;
+}
+
+static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,
+					    int orig_val)
+{
+	/*
+	 * other observers should notice all modifications
+	 * in the freezing period.
+	 */
+	smp_mb();
+	atomic_set(&grp->refcount, orig_val);
+	preempt_enable();
+}
+
+static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
+{
+	return atomic_cond_read_relaxed(&grp->refcount,
+					VAL != EROFS_LOCKED_MAGIC);
+}
 #else
+static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
+						 int val)
+{
 	preempt_disable();
-	if (atomic_read(&grp->refcount) != v) {
+	/* no need to spin on UP platforms, let's just disable preemption. */
+	if (val != atomic_read(&grp->refcount)) {
 		preempt_enable();
 		return false;
 	}
-#endif
 	return true;
 }
 
-static inline void erofs_workgroup_unfreeze(
-	struct erofs_workgroup *grp, int v)
+static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,
+					    int orig_val)
 {
-#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
-	atomic_set(&grp->refcount, v);
-#endif
 	preempt_enable();
 }
 
+static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
+{
+	int v = atomic_read(&grp->refcount);
+
+	/* workgroup is never freezed on uniprocessor systems */
+	DBG_BUGON(v == EROFS_LOCKED_MAGIC);
+	return v;
+}
+#endif
+
 static inline bool erofs_workgroup_get(struct erofs_workgroup *grp, int *ocnt)
 {
-	const int locked = (int)EROFS_LOCKED_MAGIC;
 	int o;
 
 repeat:
-	o = atomic_read(&grp->refcount);
-
-	/* spin if it is temporarily locked at the reclaim path */
-	if (unlikely(o == locked)) {
-#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
-		do
-			cpu_relax();
-		while (atomic_read(&grp->refcount) == locked);
-#endif
-		goto repeat;
-	}
+	o = erofs_wait_on_workgroup_freezed(grp);
 
 	if (unlikely(o <= 0))
 		return -1;
@@ -250,6 +270,7 @@ repeat:
 }
 
 #define __erofs_workgroup_get(grp)	atomic_inc(&(grp)->refcount)
+#define __erofs_workgroup_put(grp)	atomic_dec(&(grp)->refcount)
 
 extern int erofs_workgroup_put(struct erofs_workgroup *grp);
 
@@ -268,12 +289,14 @@ static inline void erofs_workstation_cleanup_all(struct super_block *sb)
 }
 
 #ifdef EROFS_FS_HAS_MANAGED_CACHE
-#define EROFS_UNALLOCATED_CACHED_PAGE	((void *)0x5F0EF00D)
-
 extern int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
 	struct erofs_workgroup *egrp);
 extern int erofs_try_to_free_cached_page(struct address_space *mapping,
 	struct page *page);
+
+#define MNGD_MAPPING(sbi)	((sbi)->managed_cache->i_mapping)
+#else
+#define MNGD_MAPPING(sbi)	(NULL)
 #endif
 
 #define DEFAULT_MAX_SYNC_DECOMPRESS_PAGES	3