From: Yu Kuai <yukuai3@huawei.com> Offering: HULK hulk inclusion category: bugfix bugzilla: 188902 ---------------------------------------- There are no functional changes, just to make code cleaner and prepare to fix null-ptr-dereference while accessing 'nbd->config'. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com> --- drivers/block/nbd.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 6e2eb66362c1..98127acfdea4 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -380,6 +380,14 @@ 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) { @@ -395,13 +403,13 @@ 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)) { @@ -960,12 +968,12 @@ 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), @@ -1565,6 +1573,7 @@ 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); @@ -1577,7 +1586,9 @@ 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); @@ -1592,7 +1603,7 @@ 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: @@ -2214,7 +2225,8 @@ 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); @@ -2222,7 +2234,6 @@ 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), -- 2.31.1