From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793801480; b=xumMzHhTTV+QusIXrT4l9hYJMMGkH+OMVDf27jr6LWqzTbzcbRrYXw1AW3xDv4Qx23Lr smIsd0YdurKWqWHHV/Dg5YvNiuJ/yzJLozfq15Xi2D7UL7ExmFHVJxTvcz4nEbNc/uXSI c/1RuUe9sbM/u6nqhwv3QaIrBU7t89pXBITiIudEx7th78V/IjupWDpk/wrMnbbZMD+19 rW+TgZbjjVWzVU+nRSFFzPzarce/PDW8Kz5qkpMcTxNaMVzm+MZu9wwvN7W5GVkDTIqlZ xGPi0sphZJRi4b0WkNdyosR7VLnov41qUfGttwxd1nvyVxiI3GmIjDPzUK91aOy/1Tw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793801480; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=EvU7V2odlggodyOuH+rjPVBT9c0F1hREWOVj6LzgAHU=; b=kwdpaJ8AyD/Te/cZZQZ4MFP5hUfS/byvRvbs0K8AwNtUQyZ5ZqsZ4MSr/pycdynl4NC4 oN225MkmuBlypu5MipV+P95iSYfMAjMZeC4bPRCeQfWsWq9L8jKa38+LB7ztUyfooe56U bFZQa9eQEE91mgCO0P5HiTvyhSqFXt4IHoX38KUEHr/ySAY9SrLnIgP20ywLZ9gzDTW63 uKlRuFAlorjuyhUFnTk/JZQNeFgRMEInb2vheXXO4O574LVLK8jLc+F+iZsAkab0Xec0e vZxVbqnlmku5bjS9/anY7OrC2P7g8allxrOz2MIoWqv3MaK1nmVQ8jSZV7Wbia/h/wg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="f1/Ya/4e"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E9CDB606D820; Wed, 4 Nov 2026 14:11:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=f1/Ya/4e Received: by smtp.kernel.org (Postfix) with ESMTPSA id D62331F00A15; Wed, 4 Nov 2026 14:11:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793801479; bh=EvU7V2odlggodyOuH+rjPVBT9c0F1hREWOVj6LzgAHU=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=f1/Ya/4eOJ2q8MJNQN/5cVtHA6HWEulfG8WMJKoYjlZIngBFu7rxc4C+E67yegf5p Qo1uQ9zXjw2XmABAxjpzc2rCKIQ0Aca6ebycsl7yDcWWtImVTIk3gsNyPLvghPa07q HQvvWr+hHs+l+Ls854BhbY1KUxDEIVd3ZeO17ujskn5TwIZ6MTZJ63qVQ/A8cQZ/E9 Dq7TLIWF/ReTn15xSuyK+f+5M3QYJ6WFlCbpwF9KdZSkK4QbgWflC2D9b33lzWy8a+ VaK2y2nDrpbSAnezl+AzvHzhgfMAiFH9C7g/r21KsWF6wvD7YldRLgab3IfGRRYzyd dG9ocN5pkkcOA== From: Chuck Lever Date: Wed, 04 Nov 2026 09:11:04 -0500 Subject: [PATCH v8 04/14] SUNRPC: Assign a unique identifier to each svc_xprt X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261104-duplicate-reply-cache-v8-4-eea5b90e4318@kernel.org> References: <20261104-duplicate-reply-cache-v8-0-eea5b90e4318@kernel.org> In-Reply-To: <20261104-duplicate-reply-cache-v8-0-eea5b90e4318@kernel.org> To: Jeff Layton , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: Rick Macklem , linux-nfs@vger.kernel.org, netdev@vger.kernel.org, Chuck Lever X-Mailer: b4 0.17-dev-9c833 X-Developer-Signature: v=1; a=openpgp-sha256; l=4290; i=cel@kernel.org; h=from:subject:message-id; bh=5xlo0KB7Khd0Ps2XgqBr7P43qEKbVgyFIrz9tdufqUU=; b=owEBbQKS/ZANAwAKATNqszNvZn+XAcsmYgBq6z0A8FRuARSlurbKmX/iib01bqrGKnzHSN0c+ GLCwklg2bmJAjMEAAEKAB0WIQQosuWwEobfJDzyPv4zarMzb2Z/lwUCaus9AAAKCRAzarMzb2Z/ lzCbD/45ksQpzD3NNfMbvop0RQuj87hr4ACAiKu/zdIURiQ15sgCNgOUdnBJhZwjRhECofqD/KR OzbX9U7dYV1sofNnbhtzjwg1Q7S4cYRzX1LMr1i/vuyd9CWoXiDtSA/UG3sUEV8wyLh+ecySQuV lTgWQNypLX0hK+lPpG3p9J79UxHFYp7C8/WaVfKFGesrYgWVQBolsMPmJfDSXLE63nGqOaDjU2o mzU2E087Ba4KxcXW3rcuT5ERQHbykJ3zbSRwsoKC4MFxcUTECMXCiTggiXmxE39APQaK3PnWvUd 9doSXjXAZNtPQJP3+LxnHrRJmNPiFLEdkMfTqCLipU8GqpEVj8uSzrK03R0InEWCGUf/MVPx4Js LjVDP1zRadK8rvONIDydkTraKvC+PMT6bRqyFhlZEnGADcRu4btnQOKPhiryEVbKDr1J2hZKm0k l5SNnLgUk+JihRiqpzHYPdAOiGxi6Z5+987+xRhed2DsMMdwrR+6XaBvpKFIgZ1xFDAhJFtLTb5 0gmG84Y8rLWhkf4qvhdz1b/UgdI8SYzQBW8OiOBJjps1k+Sq4ICzGl8ZV03/s3Anht+LOUfeWBk u3bdpQXi4MzTgjT/Ur/T5I8c5z3aDBY/HDhK+tneUQS5wCaEGulY6kW0Hy9mwI7gxit0bXbKCiO hwS4Y+xpbMeVrMg== X-Developer-Key: i=cel@kernel.org; a=openpgp; fpr=28B2E5B01286DF243CF23EFE336AB3336F667F97 A consumer that associates state with a transport without holding a reference cannot detect ABA collisions: once a transport is freed, SLUB may hand out a new svc_xprt at the same address. Assign each transport a 64-bit identifier from a global sequential counter in svc_xprt_init(). The counter does not wrap, so two transports never share an identifier and a consumer needs no release when the transport is freed. The NFSD duplicate reply cache is the first consumer. Reviewed-by: NeilBrown Link: https://patch.msgid.link/20260921-duplicate-reply-cache-v6-3-db5e13fd9944@kernel.org Signed-off-by: Chuck Lever --- include/linux/sunrpc/svc_xprt.h | 1 + include/trace/events/sunrpc.h | 8 ++++++-- net/sunrpc/svc_xprt.c | 17 ++++++++++++++--- 3 files changed, 21 insertions(+), 5 deletions(-) diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h index 2af222f3ea2c..52082d8ea6dd 100644 --- a/include/linux/sunrpc/svc_xprt.h +++ b/include/linux/sunrpc/svc_xprt.h @@ -56,6 +56,7 @@ struct svc_xprt { struct svc_xprt_class *xpt_class; const struct svc_xprt_ops *xpt_ops; struct kref xpt_ref; + u64 xpt_id; ktime_t xpt_qtime; struct list_head xpt_list; struct lwq_node xpt_ready; diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h index ff855197880d..77efe63d2c14 100644 --- a/include/trace/events/sunrpc.h +++ b/include/trace/events/sunrpc.h @@ -1986,7 +1986,8 @@ TRACE_EVENT(svc_xprt_create_err, __sockaddr(server, (x)->xpt_locallen) \ __sockaddr(client, (x)->xpt_remotelen) \ __field(unsigned long, flags) \ - __field(unsigned int, netns_ino) + __field(unsigned int, netns_ino) \ + __field(u64, xpt_id) #define SVC_XPRT_ENDPOINT_ASSIGNMENTS(x) \ do { \ @@ -1996,13 +1997,15 @@ TRACE_EVENT(svc_xprt_create_err, (x)->xpt_remotelen); \ __entry->flags = (x)->xpt_flags; \ __entry->netns_ino = (x)->xpt_net->ns.inum; \ + __entry->xpt_id = (x)->xpt_id; \ } while (0) #define SVC_XPRT_ENDPOINT_FORMAT \ - "server=%pISpc client=%pISpc flags=%s" + "server=%pISpc client=%pISpc xpt_id=%llu flags=%s" #define SVC_XPRT_ENDPOINT_VARARGS \ __get_sockaddr(server), __get_sockaddr(client), \ + __entry->xpt_id, \ show_svc_xprt_flags(__entry->flags) TRACE_EVENT(svc_xprt_enqueue, @@ -2024,6 +2027,7 @@ TRACE_EVENT(svc_xprt_enqueue, xprt->xpt_remotelen); __entry->flags = flags; __entry->netns_ino = xprt->xpt_net->ns.inum; + __entry->xpt_id = xprt->xpt_id; ), TP_printk(SVC_XPRT_ENDPOINT_FORMAT, SVC_XPRT_ENDPOINT_VARARGS) diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index bcc867592f2d..15c14d75ec12 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -26,6 +26,8 @@ static unsigned int svc_rpc_per_connection_limit __read_mostly; module_param(svc_rpc_per_connection_limit, uint, 0644); +static atomic64_t svc_xprt_id_seq; + static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt); static int svc_deferred_recv(struct svc_rqst *rqstp); @@ -191,9 +193,17 @@ void svc_xprt_put(struct svc_xprt *xprt) } EXPORT_SYMBOL_GPL(svc_xprt_put); -/* - * Called by transport drivers to initialize the transport independent - * portion of the transport instance. +/** + * svc_xprt_init - initialize transport-independent portion of a transport + * @net: network namespace in which the transport operates + * @xcl: transport class providing operations and metadata + * @xprt: svc_xprt to initialize + * @serv: RPC service that owns this transport + * + * @xprt->xpt_id is never reused: the 64-bit counter behind it does + * not wrap. + * + * Context: Process context. May sleep. */ void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl, struct svc_xprt *xprt, struct svc_serv *serv) @@ -211,6 +221,7 @@ void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl, set_bit(XPT_BUSY, &xprt->xpt_flags); xprt->xpt_net = get_net_track(net, &xprt->ns_tracker, GFP_ATOMIC); strcpy(xprt->xpt_remotebuf, "uninitialized"); + xprt->xpt_id = atomic64_inc_return(&svc_xprt_id_seq); } EXPORT_SYMBOL_GPL(svc_xprt_init); -- 2.56.0