[PATCH 4/7] xfs: Sort delayed write buffers before dispatch

[Christoph Hellwig]

> @@ -1937,42 +1967,46 @@ xfs_flush_buftarg(
>  	xfs_buftarg_t	*target,
>  	int		wait)
>  {
> -	struct list_head tmp;
> -	xfs_buf_t	*bp, *n;
> +	xfs_buf_t	*bp;
>  	int		pincount = 0;
> +	LIST_HEAD(tmp_list);
> +	LIST_HEAD(wait_list);
>  
>  	xfs_buf_runall_queues(xfsconvertd_workqueue);
>  	xfs_buf_runall_queues(xfsdatad_workqueue);
>  	xfs_buf_runall_queues(xfslogd_workqueue);
>  
>  	set_bit(XBT_FORCE_FLUSH, &target->bt_flags);
> -	pincount = xfs_buf_delwri_split(target, &tmp, 0);
> +	pincount = xfs_buf_delwri_split(target, &tmp_list, 0);
>  
>  	/*
> -	 * Dropped the delayed write list lock, now walk the temporary list
> +	 * Dropped the delayed write list lock, now walk the temporary list.
> +	 * All I/O is issued async and then if we need to wait for completion
> +	 * we do that after issuing all the IO.
>  	 */
> -	list_for_each_entry_safe(bp, n, &tmp, b_list) {
> +	list_sort(NULL, &tmp_list, xfs_buf_cmp);
> +	while (!list_empty(&tmp_list)) {
> +		struct xfs_buf *bp;

This now has a bp variable both in functionp-wide scope and a local one
here.  Might be worth to decide for either style.

Otherwise looks good,


Reviewed-by: Christoph Hellwig <hch at lst.de>