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Sender: Chuck Lever <chucklever@gmail.com>
Subject: [PATCH v2] SUNRPC: Remove XDRBUF_SPARSE_PAGES flag in gss_proxy
 upcall
From:   Chuck Lever <chuck.lever@oracle.com>
To:     simo@redhat.com, bfields@fieldses.org
Cc:     linux-nfs@vger.kernel.org
Date:   Mon, 30 Nov 2020 14:58:19 -0500
Message-ID: <160676629926.384675.11452129892621714986.stgit@klimt.1015granger.net>
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There's no need to defer allocation of pages for the receive buffer.

- This upcall is quite infrequent
- gssp_alloc_receive_pages() can allocate the pages with GFP_KERNEL,
  unlike the transport
- gssp_alloc_receive_pages() knows exactly how many pages are needed

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/auth_gss/gss_rpc_upcall.c |   15 ++++++++++-----
 net/sunrpc/auth_gss/gss_rpc_xdr.c    |    1 -
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/net/sunrpc/auth_gss/gss_rpc_upcall.c b/net/sunrpc/auth_gss/gss_rpc_upcall.c
index af9c7f43859c..d1c003a25b0f 100644
--- a/net/sunrpc/auth_gss/gss_rpc_upcall.c
+++ b/net/sunrpc/auth_gss/gss_rpc_upcall.c
@@ -200,7 +200,7 @@ static int gssp_call(struct net *net, struct rpc_message *msg)
 
 static void gssp_free_receive_pages(struct gssx_arg_accept_sec_context *arg)
 {
-	int i;
+	unsigned int i;
 
 	for (i = 0; i < arg->npages && arg->pages[i]; i++)
 		__free_page(arg->pages[i]);
@@ -210,14 +210,19 @@ static void gssp_free_receive_pages(struct gssx_arg_accept_sec_context *arg)
 
 static int gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context *arg)
 {
+	unsigned int i;
+
 	arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
 	arg->pages = kcalloc(arg->npages, sizeof(struct page *), GFP_KERNEL);
-	/*
-	 * XXX: actual pages are allocated by xdr layer in
-	 * xdr_partial_copy_from_skb.
-	 */
 	if (!arg->pages)
 		return -ENOMEM;
+	for (i = 0; i < arg->npages; i++) {
+		arg->pages[i] = alloc_page(GFP_KERNEL);
+		if (!arg->pages[i]) {
+			gssp_free_receive_pages(arg);
+			return -ENOMEM;
+		}
+	}
 	return 0;
 }
 
diff --git a/net/sunrpc/auth_gss/gss_rpc_xdr.c b/net/sunrpc/auth_gss/gss_rpc_xdr.c
index c636c648849b..d79f12c2550a 100644
--- a/net/sunrpc/auth_gss/gss_rpc_xdr.c
+++ b/net/sunrpc/auth_gss/gss_rpc_xdr.c
@@ -771,7 +771,6 @@ void gssx_enc_accept_sec_context(struct rpc_rqst *req,
 	xdr_inline_pages(&req->rq_rcv_buf,
 		PAGE_SIZE/2 /* pretty arbitrary */,
 		arg->pages, 0 /* page base */, arg->npages * PAGE_SIZE);
-	req->rq_rcv_buf.flags |= XDRBUF_SPARSE_PAGES;
 done:
 	if (err)
 		dprintk("RPC:       gssx_enc_accept_sec_context: %d\n", err);