From: Yu Kuai yukuai3@huawei.com
Offering: HULK hulk inclusion category: bugfix bugzilla: 188902
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There are no functional changes, make the 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 | 41 +++++++++++++++++++---------------------- 1 file changed, 19 insertions(+), 22 deletions(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 57c4053e957d..b544a301a11f 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1534,17 +1534,20 @@ static int nbd_ioctl(struct block_device *bdev, fmode_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); @@ -1552,7 +1555,10 @@ static struct nbd_config *nbd_alloc_config(void) init_waitqueue_head(&config->conn_wait); config->blksize = NBD_DEF_BLKSIZE; atomic_set(&config->live_connections, 0); - return config; + nbd->config = config; + refcount_set(&nbd->config_refs, 1); + + return 0; }
static int nbd_open(struct block_device *bdev, fmode_t mode) @@ -1571,21 +1577,17 @@ static int nbd_open(struct block_device *bdev, fmode_t mode) goto out; } if (!refcount_inc_not_zero(&nbd->config_refs)) { - struct nbd_config *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); set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state); @@ -2006,22 +2008,17 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) printk(KERN_ERR "nbd: 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); printk(KERN_ERR "nbd: 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;