[PATCH v5 12/19] sunrpc: Adjust size of socket's receive page array dynamically

[cel@kernel.org]

From: Chuck Lever <chuck.lever@oracle.com>

As a step towards making NFSD's maximum rsize and wsize variable at
run-time, make sk_pages a flexible array.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/linux/sunrpc/svcsock.h | 4 +++-
 net/sunrpc/svcsock.c           | 8 ++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index bf45d9e8492a..963bbe251e52 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -40,7 +40,9 @@ struct svc_sock {
 
 	struct completion	sk_handshake_done;
 
-	struct page *		sk_pages[RPCSVC_MAXPAGES];	/* received data */
+	/* received data */
+	unsigned long		sk_maxpages;
+	struct page *		sk_pages[] __counted_by(sk_maxpages);
 };
 
 static inline u32 svc_sock_reclen(struct svc_sock *svsk)
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index d9fdc6ae8020..e1c85123b445 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -1339,7 +1339,8 @@ static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv)
 		svsk->sk_marker = xdr_zero;
 		svsk->sk_tcplen = 0;
 		svsk->sk_datalen = 0;
-		memset(&svsk->sk_pages[0], 0, sizeof(svsk->sk_pages));
+		memset(&svsk->sk_pages[0], 0,
+		       svsk->sk_maxpages * sizeof(struct page *));
 
 		tcp_sock_set_nodelay(sk);
 
@@ -1378,10 +1379,13 @@ static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
 	struct svc_sock	*svsk;
 	struct sock	*inet;
 	int		pmap_register = !(flags & SVC_SOCK_ANONYMOUS);
+	unsigned long	pages;
 
-	svsk = kzalloc(sizeof(*svsk), GFP_KERNEL);
+	pages = svc_serv_maxpages(serv);
+	svsk = kzalloc(struct_size(svsk, sk_pages, pages), GFP_KERNEL);
 	if (!svsk)
 		return ERR_PTR(-ENOMEM);
+	svsk->sk_maxpages = pages;
 
 	inet = sock->sk;
 
-- 
2.49.0