Re: [PATCH 1/2] xfs: replace iclogs circular list with a list_head

[Christoph Hellwig <hch@lst.de>]

On Tue, Jun 24, 2025 at 12:16:32PM +1000, Dave Chinner wrote:
> Hence I think that the ring should remain immutable and the
> log->l_iclog pointer retained to index the first object in the ring.
> This means we don't need a list head in the struct xlog for the
> iclog ring, we can have the ring simply contain just the iclogs as
> they currently do.

Alternatively do away with the list entirely and replace it with
an array of pointers, i.e.

	struct xlog {
		...
		struct xlog_in_core	*l_iclog;
		struct xlog_in_core	*l_iclogs[XLOG_MAX_ICLOGS];
	};

static inline struct xlog_in_core *
xlog_next_iclog(
	struct xlog_in_core	*iclog)
{
	if (iclog == iclog->ic_log->l_iclogs[log->l_iclog_bufs - 1])
		return iclog->ic_log->l_iclogs[0];
	return iclog + 1;
}

and the typical loop become something like:

	struct xlog_in_core	*iclog = log->l_iclog;

	do {
		...
	} while ((iclog = xlog_next_iclog(iclog)) != log->l_iclog);