nfs: remove data list from pgio header

Since the ability to split pages into subpage requests has been added,
nfs_pgio_header->rpc_list only ever has one pgio data.
Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/pagelist.c

@@ -470,7 +470,6 @@ struct nfs_rw_header *nfs_rw_header_alloc(const struct nfs_rw_ops *ops)
 		struct nfs_pgio_header *hdr = &header->header;
 
 		INIT_LIST_HEAD(&hdr->pages);
-		INIT_LIST_HEAD(&hdr->rpc_list);
 		spin_lock_init(&hdr->lock);
 		atomic_set(&hdr->refcnt, 0);
 		hdr->rw_ops = ops;
@@ -648,27 +647,6 @@ int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_data *data,
 }
 EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
 
-static int nfs_do_multiple_pgios(struct list_head *head,
-				 const struct rpc_call_ops *call_ops,
-				 int how)
-{
-	struct nfs_pgio_data *data;
-	int ret = 0;
-
-	while (!list_empty(head)) {
-		int ret2;
-
-		data = list_first_entry(head, struct nfs_pgio_data, list);
-		list_del_init(&data->list);
-
-		ret2 = nfs_initiate_pgio(NFS_CLIENT(data->header->inode),
-					 data, call_ops, how, 0);
-		if (ret == 0)
-			 ret = ret2;
-	}
-	return ret;
-}
-
 /**
  * nfs_pgio_error - Clean up from a pageio error
  * @desc: IO descriptor
@@ -677,14 +655,9 @@ static int nfs_do_multiple_pgios(struct list_head *head,
 static int nfs_pgio_error(struct nfs_pageio_descriptor *desc,
 			  struct nfs_pgio_header *hdr)
 {
-	struct nfs_pgio_data *data;
-
 	set_bit(NFS_IOHDR_REDO, &hdr->flags);
-	while (!list_empty(&hdr->rpc_list)) {
-		data = list_first_entry(&hdr->rpc_list, struct nfs_pgio_data, list);
-		list_del(&data->list);
-		nfs_pgio_data_release(data);
-	}
+	nfs_pgio_data_release(hdr->data);
+	hdr->data = NULL;
 	desc->pg_completion_ops->error_cleanup(&desc->pg_list);
 	return -ENOMEM;
 }
@@ -794,7 +767,7 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
 
 	/* Set up the argument struct */
 	nfs_pgio_rpcsetup(data, desc->pg_count, 0, desc->pg_ioflags, &cinfo);
-	list_add(&data->list, &hdr->rpc_list);
+	hdr->data = data;
 	desc->pg_rpc_callops = &nfs_pgio_common_ops;
 	return 0;
 }
@@ -816,9 +789,9 @@ static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
 	atomic_inc(&hdr->refcnt);
 	ret = nfs_generic_pgio(desc, hdr);
 	if (ret == 0)
-		ret = nfs_do_multiple_pgios(&hdr->rpc_list,
-					    desc->pg_rpc_callops,
-					    desc->pg_ioflags);
+		ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
+					hdr->data, desc->pg_rpc_callops,
+					desc->pg_ioflags, 0);
 	if (atomic_dec_and_test(&hdr->refcnt))
 		hdr->completion_ops->completion(hdr);
 	return ret;

fs/nfs/pnfs.c

@@ -1573,23 +1573,18 @@ pnfs_try_to_write_data(struct nfs_pgio_data *wdata,
 }
 
 static void
-pnfs_do_multiple_writes(struct nfs_pageio_descriptor *desc, struct list_head *head, int how)
+pnfs_do_write(struct nfs_pageio_descriptor *desc,
+	      struct nfs_pgio_header *hdr, int how)
 {
-	struct nfs_pgio_data *data;
+	struct nfs_pgio_data *data = hdr->data;
 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
+	enum pnfs_try_status trypnfs;
 
 	desc->pg_lseg = NULL;
-	while (!list_empty(head)) {
-		enum pnfs_try_status trypnfs;
-
-		data = list_first_entry(head, struct nfs_pgio_data, list);
-		list_del_init(&data->list);
-
-		trypnfs = pnfs_try_to_write_data(data, call_ops, lseg, how);
-		if (trypnfs == PNFS_NOT_ATTEMPTED)
-			pnfs_write_through_mds(desc, data);
-	}
+	trypnfs = pnfs_try_to_write_data(data, call_ops, lseg, how);
+	if (trypnfs == PNFS_NOT_ATTEMPTED)
+		pnfs_write_through_mds(desc, data);
 	pnfs_put_lseg(lseg);
 }
 
@@ -1623,7 +1618,7 @@ pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
 		pnfs_put_lseg(desc->pg_lseg);
 		desc->pg_lseg = NULL;
 	} else
-		pnfs_do_multiple_writes(desc, &hdr->rpc_list, desc->pg_ioflags);
+		pnfs_do_write(desc, hdr, desc->pg_ioflags);
 	if (atomic_dec_and_test(&hdr->refcnt))
 		hdr->completion_ops->completion(hdr);
 	return ret;
@@ -1731,23 +1726,17 @@ pnfs_try_to_read_data(struct nfs_pgio_data *rdata,
 }
 
 static void
-pnfs_do_multiple_reads(struct nfs_pageio_descriptor *desc, struct list_head *head)
+pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
 {
-	struct nfs_pgio_data *data;
+	struct nfs_pgio_data *data = hdr->data;
 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
+	enum pnfs_try_status trypnfs;
 
 	desc->pg_lseg = NULL;
-	while (!list_empty(head)) {
-		enum pnfs_try_status trypnfs;
-
-		data = list_first_entry(head, struct nfs_pgio_data, list);
-		list_del_init(&data->list);
-
-		trypnfs = pnfs_try_to_read_data(data, call_ops, lseg);
-		if (trypnfs == PNFS_NOT_ATTEMPTED)
-			pnfs_read_through_mds(desc, data);
-	}
+	trypnfs = pnfs_try_to_read_data(data, call_ops, lseg);
+	if (trypnfs == PNFS_NOT_ATTEMPTED)
+		pnfs_read_through_mds(desc, data);
 	pnfs_put_lseg(lseg);
 }
 
@@ -1782,7 +1771,7 @@ pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
 		pnfs_put_lseg(desc->pg_lseg);
 		desc->pg_lseg = NULL;
 	} else
-		pnfs_do_multiple_reads(desc, &hdr->rpc_list);
+		pnfs_do_read(desc, hdr);
 	if (atomic_dec_and_test(&hdr->refcnt))
 		hdr->completion_ops->completion(hdr);
 	return ret;

include/linux/nfs_xdr.h

@@ -1256,11 +1256,13 @@ enum {
 	NFS_IOHDR_NEED_RESCHED,
 };
 
+struct nfs_pgio_data;
+
 struct nfs_pgio_header {
 	struct inode		*inode;
 	struct rpc_cred		*cred;
 	struct list_head	pages;
-	struct list_head	rpc_list;
+	struct nfs_pgio_data	*data;
 	atomic_t		refcnt;
 	struct nfs_page		*req;
 	struct nfs_writeverf	verf;		/* Used for writes */
@@ -1282,7 +1284,6 @@ struct nfs_pgio_header {
 
 struct nfs_pgio_data {
 	struct nfs_pgio_header	*header;
-	struct list_head	list;
 	struct rpc_task		task;
 	struct nfs_fattr	fattr;
 	struct nfs_writeverf	verf;		/* Used for writes */