Commit 77d63b9a authored by Yu Kuai's avatar Yu Kuai Committed by Zhong Jinghua
Browse files

nbd: factor out a helper to get nbd_config without holding 'config_lock' 

Offering: HULK
hulk inclusion
category: bugfix
bugzilla: 188902, https://gitee.com/openeuler/kernel/issues/I7EENU



----------------------------------------

There are no functional changes, just to make code cleaner and prepare
to fix null-ptr-dereference while accessing 'nbd->config'.

Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarZhong Jinghua <zhongjinghua@huawei.com>
parent 7b8f440b

drivers/block/nbd.c

+19 −8
Original line number Diff line number Diff line
@@ -389,6 +389,14 @@ 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))

		return nbd->config;



	return NULL;

}



static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,

						 bool reserved)

{
@@ -404,13 +412,13 @@ 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)) {
@@ -969,12 +977,12 @@ 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),
@@ -1564,6 +1572,7 @@ static int nbd_alloc_and_init_config(struct nbd_device *nbd) 
static int nbd_open(struct block_device *bdev, fmode_t mode)

{

	struct nbd_device *nbd;

	struct nbd_config *config;

	int ret = 0;



	mutex_lock(&nbd_index_mutex);
@@ -1576,7 +1585,9 @@ static int nbd_open(struct block_device *bdev, fmode_t mode) 
		ret = -ENXIO;

		goto out;

	}

	if (!refcount_inc_not_zero(&nbd->config_refs)) {



	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);
@@ -1591,7 +1602,7 @@ static int nbd_open(struct block_device *bdev, fmode_t mode) 
		refcount_inc(&nbd->refs);

		mutex_unlock(&nbd->config_lock);

		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);

	} else if (nbd_disconnected(nbd->config)) {

	} else if (nbd_disconnected(config)) {

		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);

	}

out:
@@ -2196,7 +2207,8 @@ 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);
@@ -2204,7 +2216,6 @@ 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),