-static void nfs_pagein_error(struct nfs_pageio_descriptor *desc,
- struct nfs_pgio_header *hdr)
-{
- set_bit(NFS_IOHDR_REDO, &hdr->flags);
- while (!list_empty(&hdr->rpc_list)) {
- struct nfs_read_data *data = list_first_entry(&hdr->rpc_list,
- struct nfs_read_data, list);
- list_del(&data->list);
- nfs_readdata_release(data);
- }
- desc->pg_completion_ops->error_cleanup(&desc->pg_list);
-}
-
-/*
- * Generate multiple requests to fill a single page.
- *
- * We optimize to reduce the number of read operations on the wire. If we
- * detect that we're reading a page, or an area of a page, that is past the
- * end of file, we do not generate NFS read operations but just clear the
- * parts of the page that would have come back zero from the server anyway.
- *
- * We rely on the cached value of i_size to make this determination; another
- * client can fill pages on the server past our cached end-of-file, but we
- * won't see the new data until our attribute cache is updated. This is more
- * or less conventional NFS client behavior.
- */
-static int nfs_pagein_multi(struct nfs_pageio_descriptor *desc,
- struct nfs_pgio_header *hdr)
-{
- struct nfs_page *req = hdr->req;
- struct page *page = req->wb_page;
- struct nfs_read_data *data;
- size_t rsize = desc->pg_bsize, nbytes;
- unsigned int offset;
-
- offset = 0;
- nbytes = desc->pg_count;
- do {
- size_t len = min(nbytes,rsize);
-
- data = nfs_readdata_alloc(hdr, 1);
- if (!data) {
- nfs_pagein_error(desc, hdr);
- return -ENOMEM;
- }
- data->pages.pagevec[0] = page;
- nfs_read_rpcsetup(data, len, offset);
- list_add(&data->list, &hdr->rpc_list);
- nbytes -= len;
- offset += len;
- } while (nbytes != 0);
-
- nfs_list_remove_request(req);
- nfs_list_add_request(req, &hdr->pages);
- desc->pg_rpc_callops = &nfs_read_common_ops;
- return 0;
-}
-
-static int nfs_pagein_one(struct nfs_pageio_descriptor *desc,
- struct nfs_pgio_header *hdr)
-{
- struct nfs_page *req;
- struct page **pages;
- struct nfs_read_data *data;
- struct list_head *head = &desc->pg_list;
-
- data = nfs_readdata_alloc(hdr, nfs_page_array_len(desc->pg_base,
- desc->pg_count));
- if (!data) {
- nfs_pagein_error(desc, hdr);
- return -ENOMEM;
- }
-
- pages = data->pages.pagevec;
- while (!list_empty(head)) {
- req = nfs_list_entry(head->next);
- nfs_list_remove_request(req);
- nfs_list_add_request(req, &hdr->pages);
- *pages++ = req->wb_page;
- }
-
- nfs_read_rpcsetup(data, desc->pg_count, 0);
- list_add(&data->list, &hdr->rpc_list);
- desc->pg_rpc_callops = &nfs_read_common_ops;
- return 0;
-}
-
-int nfs_generic_pagein(struct nfs_pageio_descriptor *desc,
- struct nfs_pgio_header *hdr)
-{
- if (desc->pg_bsize < PAGE_CACHE_SIZE)
- return nfs_pagein_multi(desc, hdr);
- return nfs_pagein_one(desc, hdr);
-}
-EXPORT_SYMBOL_GPL(nfs_generic_pagein);
-
-static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
-{
- struct nfs_read_header *rhdr;
- struct nfs_pgio_header *hdr;
- int ret;
-
- rhdr = nfs_readhdr_alloc();
- if (!rhdr) {
- desc->pg_completion_ops->error_cleanup(&desc->pg_list);
- return -ENOMEM;
- }
- hdr = &rhdr->header;
- nfs_pgheader_init(desc, hdr, nfs_readhdr_free);
- atomic_inc(&hdr->refcnt);
- ret = nfs_generic_pagein(desc, hdr);
- if (ret == 0)
- ret = nfs_do_multiple_reads(&hdr->rpc_list,
- desc->pg_rpc_callops);
- if (atomic_dec_and_test(&hdr->refcnt))
- hdr->completion_ops->completion(hdr);
- return ret;
-}
-
-static const struct nfs_pageio_ops nfs_pageio_read_ops = {
- .pg_test = nfs_generic_pg_test,
- .pg_doio = nfs_generic_pg_readpages,
-};
-