Re: [PATCHv2 07/17] nvme: add Clang context annotations for nvme_subsystem::lock

[Christoph Hellwig <hch@lst.de>]

> +	scoped_guard(mutex_init, &subsys->lock)
> +		INIT_LIST_HEAD(&subsys->nsheads);

Same init mess as a few patches earlier.

> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -719,7 +719,14 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
>  	INIT_WORK(&head->requeue_work, nvme_requeue_work);
>  	INIT_WORK(&head->partition_scan_work, nvme_partition_scan_work);
>  	INIT_DELAYED_WORK(&head->remove_work, nvme_remove_head_work);
> -	head->delayed_removal_secs = 0;
> +	/*
> +	 * The namespace head is not yet visible to other threads, so
> +	 * initializing delayed_removal_secs does not require holding
> +	 * subsys->lock. So suppress Clang's context analyzer warning by
> +	 * annotating initialization of delayed_removal_secs using
> +	 * context_unsafe.
> +	 */
> +	context_unsafe(head->delayed_removal_secs = 0);

head is a zeroed allocation, and we call nvme_mpath_alloc_disk
exactly once on it.  So we can just remove the initialization
of delayed_removal_secs entirely here.

> +	struct list_head	nsheads __guarded_by(&lock);
>  	char			subnqn[NVMF_NQN_SIZE];
>  	char			serial[20];
>  	char			model[40];
> @@ -562,7 +562,7 @@ struct nvme_ns_head {
>  	struct mutex		lock;
>  	unsigned long		flags;
>  	struct delayed_work	remove_work;
> -	unsigned int		delayed_removal_secs;
> +	unsigned int		delayed_removal_secs __guarded_by(&subsys->lock);

Btw, I find throwing the __guarded_by at the end of the line really
hard to read, especially with all these long lines.

What about moving them to the next line with an extra tab indent
instead?