X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=drivers%2Fblock%2Fnbd.c;h=b6414e1e645b763f619dfcf976aefcf3851d03c8;hb=b3ebe19c197b4dd8731de0ec7fd31fe9c12c774d;hp=800f131222fc8f9e8ecf9c8355f2a787a80cc5fc;hpb=3439b2a87edcdb86557b5e64787372c6f280dcba;p=platform%2Fkernel%2Flinux-starfive.git

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 800f131..b6414e1 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -67,6 +67,7 @@ struct nbd_sock {
 struct recv_thread_args {
 	struct work_struct work;
 	struct nbd_device *nbd;
+	struct nbd_sock *nsock;
 	int index;
 };
 
@@ -250,7 +251,6 @@ static void nbd_dev_remove(struct nbd_device *nbd)
 	struct gendisk *disk = nbd->disk;
 
 	del_gendisk(disk);
-	put_disk(disk);
 	blk_mq_free_tag_set(&nbd->tag_set);
 
 	/*
@@ -261,7 +261,7 @@ static void nbd_dev_remove(struct nbd_device *nbd)
 	idr_remove(&nbd_index_idr, nbd->index);
 	mutex_unlock(&nbd_index_mutex);
 	destroy_workqueue(nbd->recv_workq);
-	kfree(nbd);
+	put_disk(disk);
 }
 
 static void nbd_dev_remove_work(struct work_struct *work)
@@ -396,6 +396,22 @@ static u32 req_to_nbd_cmd_type(struct request *req)
 	}
 }
 
+static struct nbd_config *nbd_get_config_unlocked(struct nbd_device *nbd)
+{
+	if (refcount_inc_not_zero(&nbd->config_refs)) {
+		/*
+		 * Add smp_mb__after_atomic to ensure that reading nbd->config_refs
+		 * and reading nbd->config is ordered. The pair is the barrier in
+		 * nbd_alloc_and_init_config(), avoid nbd->config_refs is set
+		 * before nbd->config.
+		 */
+		smp_mb__after_atomic();
+		return nbd->config;
+	}
+
+	return NULL;
+}
+
 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req)
 {
 	struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
@@ -410,13 +426,13 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req)
 		return BLK_EH_DONE;
 	}
 
-	if (!refcount_inc_not_zero(&nbd->config_refs)) {
+	config = nbd_get_config_unlocked(nbd);
+	if (!config) {
 		cmd->status = BLK_STS_TIMEOUT;
 		__clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
 		mutex_unlock(&cmd->lock);
 		goto done;
 	}
-	config = nbd->config;
 
 	if (config->num_connections > 1 ||
 	    (config->num_connections == 1 && nbd->tag_set.timeout)) {
@@ -490,15 +506,9 @@ done:
 	return BLK_EH_DONE;
 }
 
-/*
- *  Send or receive packet. Return a positive value on success and
- *  negtive value on failue, and never return 0.
- */
-static int sock_xmit(struct nbd_device *nbd, int index, int send,
-		     struct iov_iter *iter, int msg_flags, int *sent)
+static int __sock_xmit(struct nbd_device *nbd, struct socket *sock, int send,
+		       struct iov_iter *iter, int msg_flags, int *sent)
 {
-	struct nbd_config *config = nbd->config;
-	struct socket *sock = config->socks[index]->sock;
 	int result;
 	struct msghdr msg;
 	unsigned int noreclaim_flag;
@@ -542,6 +552,19 @@ static int sock_xmit(struct nbd_device *nbd, int index, int send,
 }
 
 /*
+ *  Send or receive packet. Return a positive value on success and
+ *  negtive value on failure, and never return 0.
+ */
+static int sock_xmit(struct nbd_device *nbd, int index, int send,
+		     struct iov_iter *iter, int msg_flags, int *sent)
+{
+	struct nbd_config *config = nbd->config;
+	struct socket *sock = config->socks[index]->sock;
+
+	return __sock_xmit(nbd, sock, send, iter, msg_flags, sent);
+}
+
+/*
  * Different settings for sk->sk_sndtimeo can result in different return values
  * if there is a signal pending when we enter sendmsg, because reasons?
  */
@@ -697,7 +720,7 @@ out:
 	return 0;
 }
 
-static int nbd_read_reply(struct nbd_device *nbd, int index,
+static int nbd_read_reply(struct nbd_device *nbd, struct socket *sock,
 			  struct nbd_reply *reply)
 {
 	struct kvec iov = {.iov_base = reply, .iov_len = sizeof(*reply)};
@@ -706,7 +729,7 @@ static int nbd_read_reply(struct nbd_device *nbd, int index,
 
 	reply->magic = 0;
 	iov_iter_kvec(&to, ITER_DEST, &iov, 1, sizeof(*reply));
-	result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
+	result = __sock_xmit(nbd, sock, 0, &to, MSG_WAITALL, NULL);
 	if (result < 0) {
 		if (!nbd_disconnected(nbd->config))
 			dev_err(disk_to_dev(nbd->disk),
@@ -830,14 +853,14 @@ static void recv_work(struct work_struct *work)
 	struct nbd_device *nbd = args->nbd;
 	struct nbd_config *config = nbd->config;
 	struct request_queue *q = nbd->disk->queue;
-	struct nbd_sock *nsock;
+	struct nbd_sock *nsock = args->nsock;
 	struct nbd_cmd *cmd;
 	struct request *rq;
 
 	while (1) {
 		struct nbd_reply reply;
 
-		if (nbd_read_reply(nbd, args->index, &reply))
+		if (nbd_read_reply(nbd, nsock->sock, &reply))
 			break;
 
 		/*
@@ -872,7 +895,6 @@ static void recv_work(struct work_struct *work)
 		percpu_ref_put(&q->q_usage_counter);
 	}
 
-	nsock = config->socks[args->index];
 	mutex_lock(&nsock->tx_lock);
 	nbd_mark_nsock_dead(nbd, nsock, 1);
 	mutex_unlock(&nsock->tx_lock);
@@ -978,12 +1000,12 @@ static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
 	struct nbd_sock *nsock;
 	int ret;
 
-	if (!refcount_inc_not_zero(&nbd->config_refs)) {
+	config = nbd_get_config_unlocked(nbd);
+	if (!config) {
 		dev_err_ratelimited(disk_to_dev(nbd->disk),
 				    "Socks array is empty\n");
 		return -EINVAL;
 	}
-	config = nbd->config;
 
 	if (index >= config->num_connections) {
 		dev_err_ratelimited(disk_to_dev(nbd->disk),
@@ -1216,6 +1238,7 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
 		INIT_WORK(&args->work, recv_work);
 		args->index = i;
 		args->nbd = nbd;
+		args->nsock = nsock;
 		nsock->cookie++;
 		mutex_unlock(&nsock->tx_lock);
 		sockfd_put(old);
@@ -1398,6 +1421,7 @@ static int nbd_start_device(struct nbd_device *nbd)
 		refcount_inc(&nbd->config_refs);
 		INIT_WORK(&args->work, recv_work);
 		args->nbd = nbd;
+		args->nsock = config->socks[i];
 		args->index = i;
 		queue_work(nbd->recv_workq, &args->work);
 	}
@@ -1531,17 +1555,20 @@ static int nbd_ioctl(struct block_device *bdev, blk_mode_t mode,
 	return error;
 }
 
-static struct nbd_config *nbd_alloc_config(void)
+static int nbd_alloc_and_init_config(struct nbd_device *nbd)
 {
 	struct nbd_config *config;
 
+	if (WARN_ON(nbd->config))
+		return -EINVAL;
+
 	if (!try_module_get(THIS_MODULE))
-		return ERR_PTR(-ENODEV);
+		return -ENODEV;
 
 	config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
 	if (!config) {
 		module_put(THIS_MODULE);
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	}
 
 	atomic_set(&config->recv_threads, 0);
@@ -1549,12 +1576,24 @@ static struct nbd_config *nbd_alloc_config(void)
 	init_waitqueue_head(&config->conn_wait);
 	config->blksize_bits = NBD_DEF_BLKSIZE_BITS;
 	atomic_set(&config->live_connections, 0);
-	return config;
+
+	nbd->config = config;
+	/*
+	 * Order refcount_set(&nbd->config_refs, 1) and nbd->config assignment,
+	 * its pair is the barrier in nbd_get_config_unlocked().
+	 * So nbd_get_config_unlocked() won't see nbd->config as null after
+	 * refcount_inc_not_zero() succeed.
+	 */
+	smp_mb__before_atomic();
+	refcount_set(&nbd->config_refs, 1);
+
+	return 0;
 }
 
 static int nbd_open(struct gendisk *disk, blk_mode_t mode)
 {
 	struct nbd_device *nbd;
+	struct nbd_config *config;
 	int ret = 0;
 
 	mutex_lock(&nbd_index_mutex);
@@ -1567,27 +1606,25 @@ static int nbd_open(struct gendisk *disk, blk_mode_t mode)
 		ret = -ENXIO;
 		goto out;
 	}
-	if (!refcount_inc_not_zero(&nbd->config_refs)) {
-		struct nbd_config *config;
 
+	config = nbd_get_config_unlocked(nbd);
+	if (!config) {
 		mutex_lock(&nbd->config_lock);
 		if (refcount_inc_not_zero(&nbd->config_refs)) {
 			mutex_unlock(&nbd->config_lock);
 			goto out;
 		}
-		config = nbd_alloc_config();
-		if (IS_ERR(config)) {
-			ret = PTR_ERR(config);
+		ret = nbd_alloc_and_init_config(nbd);
+		if (ret) {
 			mutex_unlock(&nbd->config_lock);
 			goto out;
 		}
-		nbd->config = config;
-		refcount_set(&nbd->config_refs, 1);
+
 		refcount_inc(&nbd->refs);
 		mutex_unlock(&nbd->config_lock);
 		if (max_part)
 			set_bit(GD_NEED_PART_SCAN, &disk->state);
-	} else if (nbd_disconnected(nbd->config)) {
+	} else if (nbd_disconnected(config)) {
 		if (max_part)
 			set_bit(GD_NEED_PART_SCAN, &disk->state);
 	}
@@ -1608,6 +1645,13 @@ static void nbd_release(struct gendisk *disk)
 	nbd_put(nbd);
 }
 
+static void nbd_free_disk(struct gendisk *disk)
+{
+	struct nbd_device *nbd = disk->private_data;
+
+	kfree(nbd);
+}
+
 static const struct block_device_operations nbd_fops =
 {
 	.owner =	THIS_MODULE,
@@ -1615,6 +1659,7 @@ static const struct block_device_operations nbd_fops =
 	.release =	nbd_release,
 	.ioctl =	nbd_ioctl,
 	.compat_ioctl =	nbd_ioctl,
+	.free_disk =	nbd_free_disk,
 };
 
 #if IS_ENABLED(CONFIG_DEBUG_FS)
@@ -1983,22 +2028,17 @@ again:
 		pr_err("nbd%d already in use\n", index);
 		return -EBUSY;
 	}
-	if (WARN_ON(nbd->config)) {
-		mutex_unlock(&nbd->config_lock);
-		nbd_put(nbd);
-		return -EINVAL;
-	}
-	config = nbd_alloc_config();
-	if (IS_ERR(config)) {
+
+	ret = nbd_alloc_and_init_config(nbd);
+	if (ret) {
 		mutex_unlock(&nbd->config_lock);
 		nbd_put(nbd);
 		pr_err("couldn't allocate config\n");
-		return PTR_ERR(config);
+		return ret;
 	}
-	nbd->config = config;
-	refcount_set(&nbd->config_refs, 1);
-	set_bit(NBD_RT_BOUND, &config->runtime_flags);
 
+	config = nbd->config;
+	set_bit(NBD_RT_BOUND, &config->runtime_flags);
 	ret = nbd_genl_size_set(info, nbd);
 	if (ret)
 		goto out;
@@ -2201,7 +2241,8 @@ static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
 	}
 	mutex_unlock(&nbd_index_mutex);
 
-	if (!refcount_inc_not_zero(&nbd->config_refs)) {
+	config = nbd_get_config_unlocked(nbd);
+	if (!config) {
 		dev_err(nbd_to_dev(nbd),
 			"not configured, cannot reconfigure\n");
 		nbd_put(nbd);
@@ -2209,7 +2250,6 @@ static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	mutex_lock(&nbd->config_lock);
-	config = nbd->config;
 	if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
 	    !nbd->pid) {
 		dev_err(nbd_to_dev(nbd),