Re: [PATCH 1/2] block: pass a minsize argument to bio_iov_iter_bounce

[Matthew Wilcox <willy@infradead.org>]

On Thu, Apr 30, 2026 at 03:20:04PM +0200, Christoph Hellwig wrote:
> -static struct folio *folio_alloc_greedy(gfp_t gfp, size_t *size)
> +static struct folio *folio_alloc_greedy(gfp_t gfp, size_t *size,
> +		size_t minsize)
>  {
>  	struct folio *folio;
>  
> -	while (*size > PAGE_SIZE) {
> +	while (*size > minsize) {
>  		folio = folio_alloc(gfp | __GFP_NORETRY, get_order(*size));
>  		if (folio)
>  			return folio;

Seems a bit inefficient.  How about something like this:

static struct folio *folio_alloc_greedy(gfp_t gfp, size_t *size, size_t minsize)
{
        unsigned int order = get_order(*size);
        unsigned int minorder = get_order(minsize);
        struct folio *folio;

        while (order > minorder) {
                folio = folio_alloc(gfp | __GFP_NORETRY, order);
                if (folio)
                        return folio;
                order--;
                *size = 1UL << order;
        }

        return folio_alloc(gfp, order);
}