Merge patch series "lockref cleanups"

Christoph Hellwig <hch@lst.de> says:

This series has a bunch of cosmetic cleanups for the lockref code I came up
with when reading the code in preparation of adding a new user of it.

* patches from https://lore.kernel.org/r/20250115094702.504610-1-hch@lst.de:
  gfs2: use lockref_init for qd_lockref
  erofs: use lockref_init for pcl->lockref
  dcache: use lockref_init for d_lockref
  lockref: add a lockref_init helper
  lockref: drop superfluous externs
  lockref: use bool for false/true returns
  lockref: improve the lockref_get_not_zero description
  lockref: remove lockref_put_not_zero

Link: https://lore.kernel.org/r/20250115094702.504610-1-hch@lst.de
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/dcache.c

@@ -1681,9 +1681,8 @@ static struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
 	/* Make sure we always see the terminating NUL character */
 	smp_store_release(&dentry->d_name.name, dname); /* ^^^ */
 
-	dentry->d_lockref.count = 1;
 	dentry->d_flags = 0;
-	spin_lock_init(&dentry->d_lock);
+	lockref_init(&dentry->d_lockref, 1);
 	seqcount_spinlock_init(&dentry->d_seq, &dentry->d_lock);
 	dentry->d_inode = NULL;
 	dentry->d_parent = dentry;

fs/erofs/zdata.c

@@ -747,8 +747,7 @@ static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe)
 	if (IS_ERR(pcl))
 		return PTR_ERR(pcl);
 
-	spin_lock_init(&pcl->lockref.lock);
+	lockref_init(&pcl->lockref, 1); /* one ref for this request */
-	pcl->lockref.count = 1;		/* one ref for this request */
 	pcl->algorithmformat = map->m_algorithmformat;
 	pcl->length = 0;
 	pcl->partial = true;

fs/gfs2/quota.c

@@ -236,8 +236,7 @@ static struct gfs2_quota_data *qd_alloc(unsigned hash, struct gfs2_sbd *sdp, str
 		return NULL;
 
 	qd->qd_sbd = sdp;
-	qd->qd_lockref.count = 0;
+	lockref_init(&qd->qd_lockref, 0);
-	spin_lock_init(&qd->qd_lockref.lock);
 	qd->qd_id = qid;
 	qd->qd_slot = -1;
 	INIT_LIST_HEAD(&qd->qd_lru);

include/linux/lockref.h

@@ -34,14 +34,24 @@ struct lockref {
 	};
 };
 
-extern void lockref_get(struct lockref *);
+/**
-extern int lockref_put_return(struct lockref *);
+ * lockref_init - Initialize a lockref
-extern int lockref_get_not_zero(struct lockref *);
+ * @lockref: pointer to lockref structure
-extern int lockref_put_not_zero(struct lockref *);
+ * @count: initial count
-extern int lockref_put_or_lock(struct lockref *);
+ */
+static inline void lockref_init(struct lockref *lockref, unsigned int count)
+{
+	spin_lock_init(&lockref->lock);
+	lockref->count = count;
+}
 
-extern void lockref_mark_dead(struct lockref *);
+void lockref_get(struct lockref *lockref);
-extern int lockref_get_not_dead(struct lockref *);
+int lockref_put_return(struct lockref *lockref);
+bool lockref_get_not_zero(struct lockref *lockref);
+bool lockref_put_or_lock(struct lockref *lockref);
+
+void lockref_mark_dead(struct lockref *lockref);
+bool lockref_get_not_dead(struct lockref *lockref);
 
 /* Must be called under spinlock for reliable results */
 static inline bool __lockref_is_dead(const struct lockref *l)

lib/lockref.c

@@ -58,63 +58,34 @@ EXPORT_SYMBOL(lockref_get);
  * @lockref: pointer to lockref structure
  * Return: 1 if count updated successfully or 0 if count was zero
  */
-int lockref_get_not_zero(struct lockref *lockref)
+bool lockref_get_not_zero(struct lockref *lockref)
 {
-	int retval;
+	bool retval = false;
 
 	CMPXCHG_LOOP(
 		new.count++;
 		if (old.count <= 0)
-			return 0;
+			return false;
 	,
-		return 1;
+		return true;
 	);
 
 	spin_lock(&lockref->lock);
-	retval = 0;
 	if (lockref->count > 0) {
 		lockref->count++;
-		retval = 1;
+		retval = true;
 	}
 	spin_unlock(&lockref->lock);
 	return retval;
 }
 EXPORT_SYMBOL(lockref_get_not_zero);
 
-/**
- * lockref_put_not_zero - Decrements count unless count <= 1 before decrement
- * @lockref: pointer to lockref structure
- * Return: 1 if count updated successfully or 0 if count would become zero
- */
-int lockref_put_not_zero(struct lockref *lockref)
-{
-	int retval;
-
-	CMPXCHG_LOOP(
-		new.count--;
-		if (old.count <= 1)
-			return 0;
-	,
-		return 1;
-	);
-
-	spin_lock(&lockref->lock);
-	retval = 0;
-	if (lockref->count > 1) {
-		lockref->count--;
-		retval = 1;
-	}
-	spin_unlock(&lockref->lock);
-	return retval;
-}
-EXPORT_SYMBOL(lockref_put_not_zero);
-
 /**
  * lockref_put_return - Decrement reference count if possible
  * @lockref: pointer to lockref structure
  *
  * Decrement the reference count and return the new value.
- * If the lockref was dead or locked, return an error.
+ * If the lockref was dead or locked, return -1.
  */
 int lockref_put_return(struct lockref *lockref)
 {
@@ -134,22 +105,22 @@ EXPORT_SYMBOL(lockref_put_return);
  * @lockref: pointer to lockref structure
  * Return: 1 if count updated successfully or 0 if count <= 1 and lock taken
  */
-int lockref_put_or_lock(struct lockref *lockref)
+bool lockref_put_or_lock(struct lockref *lockref)
 {
 	CMPXCHG_LOOP(
 		new.count--;
 		if (old.count <= 1)
 			break;
 	,
-		return 1;
+		return true;
 	);
 
 	spin_lock(&lockref->lock);
 	if (lockref->count <= 1)
-		return 0;
+		return false;
 	lockref->count--;
 	spin_unlock(&lockref->lock);
-	return 1;
+	return true;
 }
 EXPORT_SYMBOL(lockref_put_or_lock);
 
@@ -169,23 +140,22 @@ EXPORT_SYMBOL(lockref_mark_dead);
  * @lockref: pointer to lockref structure
  * Return: 1 if count updated successfully or 0 if lockref was dead
  */
-int lockref_get_not_dead(struct lockref *lockref)
+bool lockref_get_not_dead(struct lockref *lockref)
 {
-	int retval;
+	bool retval = false;
 
 	CMPXCHG_LOOP(
 		new.count++;
 		if (old.count < 0)
-			return 0;
+			return false;
 	,
-		return 1;
+		return true;
 	);
 
 	spin_lock(&lockref->lock);
-	retval = 0;
 	if (lockref->count >= 0) {
 		lockref->count++;
-		retval = 1;
+		retval = true;
 	}
 	spin_unlock(&lockref->lock);
 	return retval;