[PATCH AUTOSEL 6.6 11/40] nbd: fold nbd config initialization into nbd_alloc_config()

Sasha Levin
2023-11-28T21:07:08Z

From: Li Nan <linan122@huawei.com>

[ Upstream commit 1b59860540a4018e8071dc18d4893ec389506b7d ]

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

Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20231116162316.1740402-2-linan666@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 855fdf5c3b4ea..02f844832d912 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1530,17 +1530,20 @@ 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);
@@ -1548,7 +1551,10 @@ 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;
+ refcount_set(&nbd->config_refs, 1);
+
+ return 0;
}

static int nbd_open(struct gendisk *disk, blk_mode_t mode)
@@ -1567,21 +1573,17 @@ static int nbd_open(struct gendisk *disk, blk_mode_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);
if (max_part)
@@ -1990,22 +1992,17 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
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;
--
2.42.0