NFS: Create an read_pageio_init() function

pNFS needs to select a read function based on the layout driver
currently in use, so I let each NFS version decide how to best handle
initializing reads.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/internal.h

@@ -306,7 +306,7 @@ extern int nfs_initiate_read(struct rpc_clnt *clnt,
 extern void nfs_read_prepare(struct rpc_task *task, void *calldata);
 extern int nfs_generic_pagein(struct nfs_pageio_descriptor *desc,
 			      struct nfs_pgio_header *hdr);
-extern void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio,
+extern void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
 			struct inode *inode,
 			const struct nfs_pgio_completion_ops *compl_ops);
 extern void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio);

fs/nfs/nfs3proc.c

@@ -921,6 +921,7 @@ const struct nfs_rpc_ops nfs_v3_clientops = {
 	.pathconf	= nfs3_proc_pathconf,
 	.decode_dirent	= nfs3_decode_dirent,
 	.read_setup	= nfs3_proc_read_setup,
+	.read_pageio_init = nfs_pageio_init_read,
 	.read_rpc_prepare = nfs3_proc_read_rpc_prepare,
 	.read_done	= nfs3_read_done,
 	.write_setup	= nfs3_proc_write_setup,

fs/nfs/nfs4proc.c

@@ -6792,6 +6792,7 @@ const struct nfs_rpc_ops nfs_v4_clientops = {
 	.set_capabilities = nfs4_server_capabilities,
 	.decode_dirent	= nfs4_decode_dirent,
 	.read_setup	= nfs4_proc_read_setup,
+	.read_pageio_init = pnfs_pageio_init_read,
 	.read_rpc_prepare = nfs4_proc_read_rpc_prepare,
 	.read_done	= nfs4_read_done,
 	.write_setup	= nfs4_proc_write_setup,

fs/nfs/pnfs.c

@@ -1209,7 +1209,7 @@ pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
 
-bool
+void
 pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
 		      const struct nfs_pgio_completion_ops *compl_ops)
 {
@@ -1217,10 +1217,9 @@ pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
 	struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
 
 	if (ld == NULL)
-		return false;
-	nfs_pageio_init(pgio, inode, ld->pg_read_ops, compl_ops,
-			server->rsize, 0);
-	return true;
+		nfs_pageio_init_read(pgio, inode, compl_ops);
+	else
+		nfs_pageio_init(pgio, inode, ld->pg_read_ops, compl_ops, server->rsize, 0);
 }
 
 bool
@@ -1427,7 +1426,7 @@ int pnfs_read_done_resend_to_mds(struct inode *inode,
 	LIST_HEAD(failed);
 
 	/* Resend all requests through the MDS */
-	nfs_pageio_init_read_mds(&pgio, inode, compl_ops);
+	nfs_pageio_init_read(&pgio, inode, compl_ops);
 	while (!list_empty(head)) {
 		struct nfs_page *req = nfs_list_entry(head->next);
 

fs/nfs/pnfs.h

@@ -178,7 +178,7 @@ extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp);
 void get_layout_hdr(struct pnfs_layout_hdr *lo);
 void put_lseg(struct pnfs_layout_segment *lseg);
 
-bool pnfs_pageio_init_read(struct nfs_pageio_descriptor *, struct inode *,
+void pnfs_pageio_init_read(struct nfs_pageio_descriptor *, struct inode *,
 			   const struct nfs_pgio_completion_ops *);
 bool pnfs_pageio_init_write(struct nfs_pageio_descriptor *, struct inode *,
 			    int, const struct nfs_pgio_completion_ops *);
@@ -438,10 +438,10 @@ static inline void unset_pnfs_layoutdriver(struct nfs_server *s)
 {
 }
 
-static inline bool pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
+static inline void pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
 					 const struct nfs_pgio_completion_ops *compl_ops)
 {
-	return false;
+	nfs_pageio_init_read(pgio, inode, compl_ops);
 }
 
 static inline bool pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode, int ioflags,

fs/nfs/proc.c

@@ -778,6 +778,7 @@ const struct nfs_rpc_ops nfs_v2_clientops = {
 	.pathconf	= nfs_proc_pathconf,
 	.decode_dirent	= nfs2_decode_dirent,
 	.read_setup	= nfs_proc_read_setup,
+	.read_pageio_init = nfs_pageio_init_read,
 	.read_rpc_prepare = nfs_proc_read_rpc_prepare,
 	.read_done	= nfs_read_done,
 	.write_setup	= nfs_proc_write_setup,

fs/nfs/read.c

@@ -20,8 +20,6 @@
 #include <linux/nfs_page.h>
 #include <linux/module.h>
 
-#include "pnfs.h"
-
 #include "nfs4_fs.h"
 #include "internal.h"
 #include "iostat.h"
@@ -108,7 +106,7 @@ int nfs_return_empty_page(struct page *page)
 	return 0;
 }
 
-void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio,
+void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
 			      struct inode *inode,
 			      const struct nfs_pgio_completion_ops *compl_ops)
 {
@@ -123,14 +121,6 @@ void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
 }
 EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
 
-void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
-			  struct inode *inode,
-			  const struct nfs_pgio_completion_ops *compl_ops)
-{
-	if (!pnfs_pageio_init_read(pgio, inode, compl_ops))
-		nfs_pageio_init_read_mds(pgio, inode, compl_ops);
-}
-
 int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
 		       struct page *page)
 {
@@ -149,7 +139,7 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
 	if (len < PAGE_CACHE_SIZE)
 		zero_user_segment(page, len, PAGE_CACHE_SIZE);
 
-	nfs_pageio_init_read(&pgio, inode, &nfs_async_read_completion_ops);
+	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
 	nfs_pageio_add_request(&pgio, new);
 	nfs_pageio_complete(&pgio);
 	NFS_I(inode)->read_io += pgio.pg_bytes_written;
@@ -652,7 +642,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
 	if (ret == 0)
 		goto read_complete; /* all pages were read */
 
-	nfs_pageio_init_read(&pgio, inode, &nfs_async_read_completion_ops);
+	NFS_PROTO(inode)->read_pageio_init(&pgio, inode, &nfs_async_read_completion_ops);
 
 	ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
 

include/linux/nfs_xdr.h

@@ -1354,6 +1354,7 @@ struct nfs_access_entry;
 struct nfs_client;
 struct rpc_timeout;
 struct nfs_client_initdata;
+struct nfs_pageio_descriptor;
 
 /*
  * RPC procedure vector for NFSv2/NFSv3 demuxing
@@ -1407,6 +1408,8 @@ struct nfs_rpc_ops {
 	int	(*set_capabilities)(struct nfs_server *, struct nfs_fh *);
 	int	(*decode_dirent)(struct xdr_stream *, struct nfs_entry *, int);
 	void	(*read_setup)   (struct nfs_read_data *, struct rpc_message *);
+	void	(*read_pageio_init)(struct nfs_pageio_descriptor *, struct inode *,
+				    const struct nfs_pgio_completion_ops *);
 	void	(*read_rpc_prepare)(struct rpc_task *, struct nfs_read_data *);
 	int	(*read_done)  (struct rpc_task *, struct nfs_read_data *);
 	void	(*write_setup)  (struct nfs_write_data *, struct rpc_message *);