Re: [PATCH] Convert NFS client to use ->readpages()

[Andrew Morton]

Trond Myklebust wrote:
> 
> +int
> +nfs_readpages(struct file *filp, struct address_space *mapping,
> +               struct list_head *pages, unsigned nr_pages)
> +{
> +       LIST_HEAD(head);
> +       struct nfs_readdesc desc = {
> +               .filp           = filp,
> +               .head           = &head,
> +       };
> +       struct nfs_server *server = NFS_SERVER(mapping->host);
> +       int is_sync = server->rsize < PAGE_CACHE_SIZE;
> +       int ret;
> +
> +       ret = read_cache_pages(mapping, pages,
> +                              is_sync ? readpage_sync_filler :
> +                                        readpage_async_filler,
> +                              &desc);
> +       if (!list_empty(pages)) {
> +               struct page *page = list_entry(pages->prev, struct page, list);
> +               list_del(&page->list);
> +               page_cache_release(page);
> +       }

What are the above few lines doing?  Looks odd.

Or should it be

	while (!list_empty(...))

?

> +       if (!list_empty(&head)) {
> +               int err = nfs_pagein_list(&head, server->rpages);
> +               if (!ret)
> +                       ret = err;
> +       }
> +       return ret;
> +}
> +