ksmbd: use rwsem instead of rwlock for lease break

lease break wait for lease break acknowledgment.
rwsem is more suitable than unlock while traversing the list for parent
lease break in ->m_op_list.

Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/server/oplock.c

@@ -207,9 +207,9 @@ static void opinfo_add(struct oplock_info *opinfo)
 {
 	struct ksmbd_inode *ci = opinfo->o_fp->f_ci;
 
-	write_lock(&ci->m_lock);
+	down_write(&ci->m_lock);
 	list_add_rcu(&opinfo->op_entry, &ci->m_op_list);
-	write_unlock(&ci->m_lock);
+	up_write(&ci->m_lock);
 }
 
 static void opinfo_del(struct oplock_info *opinfo)
@@ -221,9 +221,9 @@ static void opinfo_del(struct oplock_info *opinfo)
 		lease_del_list(opinfo);
 		write_unlock(&lease_list_lock);
 	}
-	write_lock(&ci->m_lock);
+	down_write(&ci->m_lock);
 	list_del_rcu(&opinfo->op_entry);
-	write_unlock(&ci->m_lock);
+	up_write(&ci->m_lock);
 }
 
 static unsigned long opinfo_count(struct ksmbd_file *fp)
@@ -526,21 +526,18 @@ static struct oplock_info *same_client_has_lease(struct ksmbd_inode *ci,
 	 * Compare lease key and client_guid to know request from same owner
 	 * of same client
 	 */
-	read_lock(&ci->m_lock);
+	down_read(&ci->m_lock);
 	list_for_each_entry(opinfo, &ci->m_op_list, op_entry) {
 		if (!opinfo->is_lease || !opinfo->conn)
 			continue;
-		read_unlock(&ci->m_lock);
 		lease = opinfo->o_lease;
 
 		ret = compare_guid_key(opinfo, client_guid, lctx->lease_key);
 		if (ret) {
 			m_opinfo = opinfo;
 			/* skip upgrading lease about breaking lease */
-			if (atomic_read(&opinfo->breaking_cnt)) {
-				read_lock(&ci->m_lock);
+			if (atomic_read(&opinfo->breaking_cnt))
 				continue;
-			}
 
 			/* upgrading lease */
 			if ((atomic_read(&ci->op_count) +
@@ -570,9 +567,8 @@ static struct oplock_info *same_client_has_lease(struct ksmbd_inode *ci,
 				lease_none_upgrade(opinfo, lctx->req_state);
 			}
 		}
-		read_lock(&ci->m_lock);
 	}
-	read_unlock(&ci->m_lock);
+	up_read(&ci->m_lock);
 
 	return m_opinfo;
 }
@@ -1114,7 +1110,7 @@ void smb_send_parent_lease_break_noti(struct ksmbd_file *fp,
 	if (!p_ci)
 		return;
 
-	read_lock(&p_ci->m_lock);
+	down_read(&p_ci->m_lock);
 	list_for_each_entry(opinfo, &p_ci->m_op_list, op_entry) {
 		if (opinfo->conn == NULL || !opinfo->is_lease)
 			continue;
@@ -1132,13 +1128,11 @@ void smb_send_parent_lease_break_noti(struct ksmbd_file *fp,
 				continue;
 			}
 
-			read_unlock(&p_ci->m_lock);
 			oplock_break(opinfo, SMB2_OPLOCK_LEVEL_NONE);
 			opinfo_conn_put(opinfo);
-			read_lock(&p_ci->m_lock);
 		}
 	}
-	read_unlock(&p_ci->m_lock);
+	up_read(&p_ci->m_lock);
 
 	ksmbd_inode_put(p_ci);
 }
@@ -1159,7 +1153,7 @@ void smb_lazy_parent_lease_break_close(struct ksmbd_file *fp)
 	if (!p_ci)
 		return;
 
-	read_lock(&p_ci->m_lock);
+	down_read(&p_ci->m_lock);
 	list_for_each_entry(opinfo, &p_ci->m_op_list, op_entry) {
 		if (opinfo->conn == NULL || !opinfo->is_lease)
 			continue;
@@ -1173,13 +1167,11 @@ void smb_lazy_parent_lease_break_close(struct ksmbd_file *fp)
 				atomic_dec(&opinfo->conn->r_count);
 				continue;
 			}
-			read_unlock(&p_ci->m_lock);
 			oplock_break(opinfo, SMB2_OPLOCK_LEVEL_NONE);
 			opinfo_conn_put(opinfo);
-			read_lock(&p_ci->m_lock);
 		}
 	}
-	read_unlock(&p_ci->m_lock);
+	up_read(&p_ci->m_lock);
 
 	ksmbd_inode_put(p_ci);
 }

fs/smb/server/smb2pdu.c

@@ -3376,9 +3376,9 @@ int smb2_open(struct ksmbd_work *work)
 	 * after daccess, saccess, attrib_only, and stream are
 	 * initialized.
 	 */
-	write_lock(&fp->f_ci->m_lock);
+	down_write(&fp->f_ci->m_lock);
 	list_add(&fp->node, &fp->f_ci->m_fp_list);
-	write_unlock(&fp->f_ci->m_lock);
+	up_write(&fp->f_ci->m_lock);
 
 	/* Check delete pending among previous fp before oplock break */
 	if (ksmbd_inode_pending_delete(fp)) {

fs/smb/server/smb_common.c

@@ -646,7 +646,7 @@ int ksmbd_smb_check_shared_mode(struct file *filp, struct ksmbd_file *curr_fp)
 	 * Lookup fp in master fp list, and check desired access and
 	 * shared mode between previous open and current open.
 	 */
-	read_lock(&curr_fp->f_ci->m_lock);
+	down_read(&curr_fp->f_ci->m_lock);
 	list_for_each_entry(prev_fp, &curr_fp->f_ci->m_fp_list, node) {
 		if (file_inode(filp) != file_inode(prev_fp->filp))
 			continue;
@@ -722,7 +722,7 @@ int ksmbd_smb_check_shared_mode(struct file *filp, struct ksmbd_file *curr_fp)
 			break;
 		}
 	}
-	read_unlock(&curr_fp->f_ci->m_lock);
+	up_read(&curr_fp->f_ci->m_lock);
 
 	return rc;
 }

fs/smb/server/vfs_cache.c

@@ -165,7 +165,7 @@ static int ksmbd_inode_init(struct ksmbd_inode *ci, struct ksmbd_file *fp)
 	ci->m_fattr = 0;
 	INIT_LIST_HEAD(&ci->m_fp_list);
 	INIT_LIST_HEAD(&ci->m_op_list);
-	rwlock_init(&ci->m_lock);
+	init_rwsem(&ci->m_lock);
 	ci->m_de = fp->filp->f_path.dentry;
 	return 0;
 }
@@ -261,14 +261,14 @@ static void __ksmbd_inode_close(struct ksmbd_file *fp)
 	}
 
 	if (atomic_dec_and_test(&ci->m_count)) {
-		write_lock(&ci->m_lock);
+		down_write(&ci->m_lock);
 		if (ci->m_flags & (S_DEL_ON_CLS | S_DEL_PENDING)) {
 			ci->m_flags &= ~(S_DEL_ON_CLS | S_DEL_PENDING);
-			write_unlock(&ci->m_lock);
+			up_write(&ci->m_lock);
 			ksmbd_vfs_unlink(filp);
-			write_lock(&ci->m_lock);
+			down_write(&ci->m_lock);
 		}
-		write_unlock(&ci->m_lock);
+		up_write(&ci->m_lock);
 
 		ksmbd_inode_free(ci);
 	}
@@ -289,9 +289,9 @@ static void __ksmbd_remove_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp
 	if (!has_file_id(fp->volatile_id))
 		return;
 
-	write_lock(&fp->f_ci->m_lock);
+	down_write(&fp->f_ci->m_lock);
 	list_del_init(&fp->node);
-	write_unlock(&fp->f_ci->m_lock);
+	up_write(&fp->f_ci->m_lock);
 
 	write_lock(&ft->lock);
 	idr_remove(ft->idr, fp->volatile_id);
@@ -523,17 +523,17 @@ struct ksmbd_file *ksmbd_lookup_fd_inode(struct dentry *dentry)
 	if (!ci)
 		return NULL;
 
-	read_lock(&ci->m_lock);
+	down_read(&ci->m_lock);
 	list_for_each_entry(lfp, &ci->m_fp_list, node) {
 		if (inode == file_inode(lfp->filp)) {
 			atomic_dec(&ci->m_count);
 			lfp = ksmbd_fp_get(lfp);
-			read_unlock(&ci->m_lock);
+			up_read(&ci->m_lock);
 			return lfp;
 		}
 	}
 	atomic_dec(&ci->m_count);
-	read_unlock(&ci->m_lock);
+	up_read(&ci->m_lock);
 	return NULL;
 }
 
@@ -705,13 +705,13 @@ static bool session_fd_check(struct ksmbd_tree_connect *tcon,
 
 	conn = fp->conn;
 	ci = fp->f_ci;
-	write_lock(&ci->m_lock);
+	down_write(&ci->m_lock);
 	list_for_each_entry_rcu(op, &ci->m_op_list, op_entry) {
 		if (op->conn != conn)
 			continue;
 		op->conn = NULL;
 	}
-	write_unlock(&ci->m_lock);
+	up_write(&ci->m_lock);
 
 	fp->conn = NULL;
 	fp->tcon = NULL;
@@ -801,13 +801,13 @@ int ksmbd_reopen_durable_fd(struct ksmbd_work *work, struct ksmbd_file *fp)
 	fp->tcon = work->tcon;
 
 	ci = fp->f_ci;
-	write_lock(&ci->m_lock);
+	down_write(&ci->m_lock);
 	list_for_each_entry_rcu(op, &ci->m_op_list, op_entry) {
 		if (op->conn)
 			continue;
 		op->conn = fp->conn;
 	}
-	write_unlock(&ci->m_lock);
+	up_write(&ci->m_lock);
 
 	__open_id(&work->sess->file_table, fp, OPEN_ID_TYPE_VOLATILE_ID);
 	if (!has_file_id(fp->volatile_id)) {

fs/smb/server/vfs_cache.h

@@ -47,7 +47,7 @@ struct stream {
 };
 
 struct ksmbd_inode {
-	rwlock_t			m_lock;
+	struct rw_semaphore		m_lock;
 	atomic_t			m_count;
 	atomic_t			op_count;
 	/* opinfo count for streams */