REPOST patch 13/38: CLIENT: add ->setup_read() nfs_rpc_op for async read, part 1

From: Kendrick M. Smith (kmsmith@umich.edu)
Date: Wed Aug 14 2002 - 15:42:25 EST


This is a nontrivial change to the NFS client.

Synchronous READ operations are currently done via the ->read() nfs_rpc_op.
Therefore, the synchronous READ path can easily be adapted for NFSv4. On
the other hand, the asynchronous READ path contains several NFSv3-specific
features, which make it difficult to adapt for NFSv4.

In this patch and the next, we modify the async READ path to be
version-agnostic. This patch just changes the 'struct nfs_read_data'
so that the v2- and v3-specific parts are moved into a private area,
with room for a v4-specific part in parallel. None of the logic is
changed.

--- old/fs/nfs/read.c Thu Aug 1 16:16:00 2002
+++ new/fs/nfs/read.c Sun Aug 11 20:40:06 2002
@@ -38,11 +38,18 @@ struct nfs_read_data {
         struct rpc_task task;
         struct inode *inode;
         struct rpc_cred *cred;
- struct nfs_readargs args; /* XDR argument struct */
- struct nfs_readres res; /* ... and result struct */
         struct nfs_fattr fattr; /* fattr storage */
         struct list_head pages; /* Coalesced read requests */
         struct page *pagevec[NFS_READ_MAXIOV];
+ union {
+ struct {
+ struct nfs_readargs args;
+ struct nfs_readres res;
+ } v3; /* also v2 */
+#ifdef CONFIG_NFS_V4
+ /* NFSv4 data will come here... */
+#endif
+ } u;
 };

 /*
@@ -64,7 +71,7 @@ static __inline__ struct nfs_read_data *
         if (p) {
                 memset(p, 0, sizeof(*p));
                 INIT_LIST_HEAD(&p->pages);
- p->args.pages = p->pagevec;
+ p->u.v3.args.pages = p->pagevec;
         }
         return p;
 }
@@ -194,7 +201,7 @@ nfs_read_rpcsetup(struct list_head *head
         struct page **pages;
         unsigned int count;

- pages = data->args.pages;
+ pages = data->u.v3.args.pages;
         count = 0;
         while (!list_empty(head)) {
                 struct nfs_page *req = nfs_list_entry(head->next);
@@ -206,13 +213,13 @@ nfs_read_rpcsetup(struct list_head *head
         req = nfs_list_entry(data->pages.next);
         data->inode = req->wb_inode;
         data->cred = req->wb_cred;
- data->args.fh = NFS_FH(req->wb_inode);
- data->args.offset = page_offset(req->wb_page) + req->wb_offset;
- data->args.pgbase = req->wb_offset;
- data->args.count = count;
- data->res.fattr = &data->fattr;
- data->res.count = count;
- data->res.eof = 0;
+ data->u.v3.args.fh = NFS_FH(req->wb_inode);
+ data->u.v3.args.offset = page_offset(req->wb_page) + req->wb_offset;
+ data->u.v3.args.pgbase = req->wb_offset;
+ data->u.v3.args.count = count;
+ data->u.v3.res.fattr = &data->fattr;
+ data->u.v3.res.count = count;
+ data->u.v3.res.eof = 0;
 }

 static void
@@ -264,8 +271,8 @@ nfs_pagein_one(struct list_head *head, s
 #else
         msg.rpc_proc = NFSPROC_READ;
 #endif
- msg.rpc_argp = &data->args;
- msg.rpc_resp = &data->res;
+ msg.rpc_argp = &data->u.v3.args;
+ msg.rpc_resp = &data->u.v3.res;
         msg.rpc_cred = data->cred;

         /* Start the async call */
@@ -273,8 +280,8 @@ nfs_pagein_one(struct list_head *head, s
                 task->tk_pid,
                 inode->i_sb->s_id,
                 (long long)NFS_FILEID(inode),
- (unsigned int)data->args.count,
- (unsigned long long)data->args.offset);
+ (unsigned int)data->u.v3.args.count,
+ (unsigned long long)data->u.v3.args.offset);

         rpc_clnt_sigmask(clnt, &oldset);
         rpc_call_setup(task, &msg, 0);
@@ -404,7 +411,7 @@ nfs_readpage_result(struct rpc_task *tas
 {
         struct nfs_read_data *data = (struct nfs_read_data *) task->tk_calldata;
         struct inode *inode = data->inode;
- unsigned int count = data->res.count;
+ unsigned int count = data->u.v3.res.count;

         dprintk("NFS: %4d nfs_readpage_result, (status %d)\n",
                 task->tk_pid, task->tk_status);

-
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