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

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There are no functional changes, just to make 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/20231116162316.1740402-3-linan666@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Li Nan 2023-11-17 00:23:15 +08:00 committed by Jens Axboe
parent 1b59860540
commit 3123ac7792
1 changed files with 19 additions and 8 deletions
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27
drivers/block/nbd.c
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@ -395,6 +395,14 @@ 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)
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
@ -409,13 +417,13 @@ 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)) {
@ -977,12 +985,12 @@ 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),
@ -1560,6 +1568,7 @@ static int nbd_alloc_and_init_config(struct nbd_device *nbd)
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);
@ -1572,7 +1581,9 @@ static int nbd_open(struct gendisk *disk, blk_mode_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);
@ -1588,7 +1599,7 @@ static int nbd_open(struct gendisk *disk, blk_mode_t mode)
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);
}
@ -2205,7 +2216,8 @@ 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);
@ -2213,7 +2225,6 @@ 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),