NFS: Convert the remaining pagelist helper functions to support folios

Allow creation of subrequests from a request that is carrying a folio.
Add helpers to set up and tear down requests carrying folios.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/pagelist.c

@@ -466,10 +466,9 @@ nfs_page_group_destroy(struct kref *kref)
 		nfs_release_request(head);
 }
 
-static struct nfs_page *
-__nfs_create_request(struct nfs_lock_context *l_ctx, struct page *page,
-		   unsigned int pgbase, unsigned int offset,
-		   unsigned int count)
+static struct nfs_page *nfs_page_create(struct nfs_lock_context *l_ctx,
+					unsigned int pgbase, pgoff_t index,
+					unsigned int offset, unsigned int count)
 {
 	struct nfs_page		*req;
 	struct nfs_open_context *ctx = l_ctx->open_context;
@@ -488,19 +487,32 @@ __nfs_create_request(struct nfs_lock_context *l_ctx, struct page *page,
 	/* Initialize the request struct. Initially, we assume a
 	 * long write-back delay. This will be adjusted in
 	 * update_nfs_request below if the region is not locked. */
-	req->wb_page    = page;
-	if (page) {
-		req->wb_index = page_index(page);
-		get_page(page);
-	}
-	req->wb_offset  = offset;
 	req->wb_pgbase = pgbase;
+	req->wb_index = index;
+	req->wb_offset = offset;
 	req->wb_bytes = count;
 	kref_init(&req->wb_kref);
 	req->wb_nio = 0;
 	return req;
 }
 
+static void nfs_page_assign_folio(struct nfs_page *req, struct folio *folio)
+{
+	if (folio != NULL) {
+		req->wb_folio = folio;
+		folio_get(folio);
+		set_bit(PG_FOLIO, &req->wb_flags);
+	}
+}
+
+static void nfs_page_assign_page(struct nfs_page *req, struct page *page)
+{
+	if (page != NULL) {
+		req->wb_page = page;
+		get_page(page);
+	}
+}
+
 /**
  * nfs_create_request - Create an NFS read/write request.
  * @ctx: open context to use
@@ -521,9 +533,11 @@ nfs_create_request(struct nfs_open_context *ctx, struct page *page,
 
 	if (IS_ERR(l_ctx))
 		return ERR_CAST(l_ctx);
-	ret = __nfs_create_request(l_ctx, page, offset, offset, count);
-	if (!IS_ERR(ret))
+	ret = nfs_page_create(l_ctx, offset, page_index(page), offset, count);
+	if (!IS_ERR(ret)) {
+		nfs_page_assign_page(ret, page);
 		nfs_page_group_init(ret, NULL);
+	}
 	nfs_put_lock_context(l_ctx);
 	return ret;
 }
@@ -536,11 +550,16 @@ nfs_create_subreq(struct nfs_page *req,
 {
 	struct nfs_page *last;
 	struct nfs_page *ret;
+	struct folio *folio = nfs_page_to_folio(req);
 	struct page *page = nfs_page_to_page(req, pgbase);
 
-	ret = __nfs_create_request(req->wb_lock_context, page, pgbase, offset,
-				   count);
+	ret = nfs_page_create(req->wb_lock_context, pgbase, req->wb_index,
+			      offset, count);
 	if (!IS_ERR(ret)) {
+		if (folio)
+			nfs_page_assign_folio(ret, folio);
+		else
+			nfs_page_assign_page(ret, page);
 		/* find the last request */
 		for (last = req->wb_head;
 		     last->wb_this_page != req->wb_head;
@@ -548,7 +567,6 @@ nfs_create_subreq(struct nfs_page *req,
 			;
 
 		nfs_lock_request(ret);
-		ret->wb_index = req->wb_index;
 		nfs_page_group_init(ret, last);
 		ret->wb_nio = req->wb_nio;
 	}
@@ -587,11 +605,16 @@ void nfs_unlock_and_release_request(struct nfs_page *req)
  */
 static void nfs_clear_request(struct nfs_page *req)
 {
+	struct folio *folio = nfs_page_to_folio(req);
 	struct page *page = req->wb_page;
 	struct nfs_lock_context *l_ctx = req->wb_lock_context;
 	struct nfs_open_context *ctx;
 
-	if (page != NULL) {
+	if (folio != NULL) {
+		folio_put(folio);
+		req->wb_folio = NULL;
+		clear_bit(PG_FOLIO, &req->wb_flags);
+	} else if (page != NULL) {
 		put_page(page);
 		req->wb_page = NULL;
 	}
@@ -1471,18 +1494,23 @@ void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
 {
 	struct nfs_pgio_mirror *mirror;
 	struct nfs_page *prev;
+	struct folio *folio;
 	u32 midx;
 
 	for (midx = 0; midx < desc->pg_mirror_count; midx++) {
 		mirror = nfs_pgio_get_mirror(desc, midx);
 		if (!list_empty(&mirror->pg_list)) {
 			prev = nfs_list_entry(mirror->pg_list.prev);
-			if (index != prev->wb_index + 1) {
+			folio = nfs_page_to_folio(prev);
+			if (folio) {
+				if (index == folio_next_index(folio))
+					continue;
+			} else if (index == prev->wb_index + 1)
+				continue;
 			nfs_pageio_complete(desc);
 			break;
 		}
 	}
-	}
 }
 
 /*