[PATCH] nvme: fix SRCU protection of nvme_ns_head list

[Christoph Hellwig]

On Sun, Nov 20, 2022 at 01:24:51PM +0200, Sagi Grimberg wrote:
>>   	sector_t capacity = get_capacity(head->disk);
>>   	int node;
>> +	int srcu_idx;
>>   +	srcu_idx = srcu_read_lock(&head->srcu);
>>   	list_for_each_entry_rcu(ns, &head->list, siblings) {
>>   		if (capacity != get_capacity(ns->disk))
>>   			clear_bit(NVME_NS_READY, &ns->flags);
>>   	}
>> +	srcu_read_unlock(&head->srcu, srcu_idx);
>
> I don't think you need srcu here, rcu_read_lock/unlock is sufficient.

So the code obviously does not sleep.  But I wonder if anything speaks
against mixing SRCU and RCU protection for the same list?