linux-kernel - [PATCH 02/26] net/bpfilter: split __bpfilter_process

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Date:   Thu, 23 Jul 2020 08:08:44 +0200
From:   Christoph Hellwig <hch@....de>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Eric Dumazet <edumazet@...gle.com>
Cc:     linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, bpf@...r.kernel.org,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        linux-sctp@...r.kernel.org, linux-hams@...r.kernel.org,
        linux-bluetooth@...r.kernel.org, bridge@...ts.linux-foundation.org,
        linux-can@...r.kernel.org, dccp@...r.kernel.org,
        linux-decnet-user@...ts.sourceforge.net,
        linux-wpan@...r.kernel.org, linux-s390@...r.kernel.org,
        mptcp@...ts.01.org, lvs-devel@...r.kernel.org,
        rds-devel@....oracle.com, linux-afs@...ts.infradead.org,
        tipc-discussion@...ts.sourceforge.net, linux-x25@...r.kernel.org
Subject: [PATCH 02/26] net/bpfilter: split __bpfilter_process_sockopt

Split __bpfilter_process_sockopt into a low-level send request routine and
the actual setsockopt hook to split the init time ping from the actual
setsockopt processing.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 net/bpfilter/bpfilter_kern.c | 51 +++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 24 deletions(-)

diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 3bac5820062af1..78d561f2c54da7 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -31,48 +31,51 @@ static void __stop_umh(void)
 		shutdown_umh();
 }
 
-static int __bpfilter_process_sockopt(struct sock *sk, int optname,
-				      char __user *optval,
-				      unsigned int optlen, bool is_set)
+static int bpfilter_send_req(struct mbox_request *req)
 {
-	struct mbox_request req;
 	struct mbox_reply reply;
 	loff_t pos;
 	ssize_t n;
-	int ret = -EFAULT;
 
-	req.is_set = is_set;
-	req.pid = current->pid;
-	req.cmd = optname;
-	req.addr = (uintptr_t)optval;
-	req.len = optlen;
 	if (!bpfilter_ops.info.tgid)
-		goto out;
+		return -EFAULT;
 	pos = 0;
-	n = kernel_write(bpfilter_ops.info.pipe_to_umh, &req, sizeof(req),
+	n = kernel_write(bpfilter_ops.info.pipe_to_umh, req, sizeof(*req),
 			   &pos);
-	if (n != sizeof(req)) {
+	if (n != sizeof(*req)) {
 		pr_err("write fail %zd\n", n);
-		__stop_umh();
-		ret = -EFAULT;
-		goto out;
+		goto stop;
 	}
 	pos = 0;
 	n = kernel_read(bpfilter_ops.info.pipe_from_umh, &reply, sizeof(reply),
 			&pos);
 	if (n != sizeof(reply)) {
 		pr_err("read fail %zd\n", n);
-		__stop_umh();
-		ret = -EFAULT;
-		goto out;
+		goto stop;
 	}
-	ret = reply.status;
-out:
-	return ret;
+	return reply.status;
+stop:
+	__stop_umh();
+	return -EFAULT;
+}
+
+static int bpfilter_process_sockopt(struct sock *sk, int optname,
+				    char __user *optval, unsigned int optlen,
+				    bool is_set)
+{
+	struct mbox_request req = {
+		.is_set		= is_set,
+		.pid		= current->pid,
+		.cmd		= optname,
+		.addr		= (uintptr_t)optval,
+		.len		= optlen,
+	};
+	return bpfilter_send_req(&req);
 }
 
 static int start_umh(void)
 {
+	struct mbox_request req = { .pid = current->pid };
 	int err;
 
 	/* fork usermode process */
@@ -82,7 +85,7 @@ static int start_umh(void)
 	pr_info("Loaded bpfilter_umh pid %d\n", pid_nr(bpfilter_ops.info.tgid));
 
 	/* health check that usermode process started correctly */
-	if (__bpfilter_process_sockopt(NULL, 0, NULL, 0, 0) != 0) {
+	if (bpfilter_send_req(&req) != 0) {
 		shutdown_umh();
 		return -EFAULT;
 	}
@@ -103,7 +106,7 @@ static int __init load_umh(void)
 	mutex_lock(&bpfilter_ops.lock);
 	err = start_umh();
 	if (!err && IS_ENABLED(CONFIG_INET)) {
-		bpfilter_ops.sockopt = &__bpfilter_process_sockopt;
+		bpfilter_ops.sockopt = &bpfilter_process_sockopt;
 		bpfilter_ops.start = &start_umh;
 	}
 	mutex_unlock(&bpfilter_ops.lock);
-- 
2.27.0