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From:   trondmy@kernel.org
To:     linux-nfs@vger.kernel.org
Subject: [PATCH 2/2] SUNRPC: Don't return error values in sysfs read of closed files
Date:   Thu, 24 Mar 2022 17:33:45 -0400
Message-Id: <20220324213345.5833-2-trondmy@kernel.org>
In-Reply-To: <20220324213345.5833-1-trondmy@kernel.org>
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From: Trond Myklebust <trond.myklebust@hammerspace.com>

Instead of returning an error value, which ends up being the return
value for the read() system call, it is more elegant to simply return
the error as a string value.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 net/sunrpc/sysfs.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c
index 8ce053f84421..796e0f141282 100644
--- a/net/sunrpc/sysfs.c
+++ b/net/sunrpc/sysfs.c
@@ -93,10 +93,13 @@ static ssize_t rpc_sysfs_xprt_dstaddr_show(struct kobject *kobj,
 	struct rpc_xprt *xprt = rpc_sysfs_xprt_kobj_get_xprt(kobj);
 	ssize_t ret;
 
-	if (!xprt)
-		return 0;
+	if (!xprt) {
+		ret = sprintf(buf, "<closed>\n");
+		goto out;
+	}
 	ret = sprintf(buf, "%s\n", xprt->address_strings[RPC_DISPLAY_ADDR]);
 	xprt_put(xprt);
+out:
 	return ret + 1;
 }
 
@@ -147,8 +150,8 @@ static ssize_t rpc_sysfs_xprt_info_show(struct kobject *kobj,
 	ssize_t ret;
 
 	if (!xprt || !xprt_connected(xprt)) {
-		xprt_put(xprt);
-		return -ENOTCONN;
+		ret = sprintf(buf, "<closed>\n");
+		goto out;
 	}
 
 	ret = sprintf(buf, "last_used=%lu\ncur_cong=%lu\ncong_win=%lu\n"
@@ -165,6 +168,7 @@ static ssize_t rpc_sysfs_xprt_info_show(struct kobject *kobj,
 		       atomic_long_read(&xprt->queuelen),
 		       (xprt->xprt_class->ident == XPRT_TRANSPORT_TCP) ?
 				xprt->address_strings[RPC_DISPLAY_PORT] : "0");
+out:
 	xprt_put(xprt);
 	return ret + 1;
 }
@@ -178,10 +182,7 @@ static ssize_t rpc_sysfs_xprt_state_show(struct kobject *kobj,
 	int locked, connected, connecting, close_wait, bound, binding,
 	    closing, congested, cwnd_wait, write_space, offline, remove;
 
-	if (!xprt)
-		return 0;
-
-	if (!xprt->state) {
+	if (!(xprt && xprt->state)) {
 		ret = sprintf(buf, "state=CLOSED\n");
 	} else {
 		locked = test_bit(XPRT_LOCKED, &xprt->state);
-- 
2.35.1