From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 433D030C143; Thu, 30 Jul 2026 15:50:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785426620; cv=none; b=URa4kwkoKKyxoHjeBj5FgEL19bfFXXGInCoyPrCAdIMENrlkcEYBLunEE/1pnacFkXWcj7Q4WdQRnYcy41Is48lM983rCiube6FOfbb+4YJo9PmQdPfbHbgCmewso5X9RhYj0OwC1UiGqVKn2sCCy+eh/Yg9NGRSSQxG0K+7BzQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785426620; c=relaxed/simple; bh=0rpNUkXqQZMXpJ9cXakQDWNvQasF/ZoIbB0OJgDOhZM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TsI+n6YKdKTHRC1FrVVK2C4vx5+7+4eJ8zLCHyHGoXIDOTaweaZ8JoFYStRzowKWVCwNUsem5Byrj66yhZQ/20sVhr1BHe0NRoiZ0Z6jeG/kpJYXjKRvpUiaIXhHdiA0qjfFHxoN1FZC6kjiHpuAOdbvbfweCxu+BSGyJmcOaxg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BnU9Uz27; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BnU9Uz27" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 514F51F000E9; Thu, 30 Jul 2026 15:50:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785426618; bh=k8qUQMZGQPEHQlXd2fYytPA8iVNzrFKUVlFImDHLENE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=BnU9Uz27A9WFO+F3nknxrMLqWEvdQM6Eu9z20XE+1yN+wh5JJOsvV7FEGPosV4L4W lmYagCTjn4M5TcViiNznXucLZsJk5hF/cqX1wf5vEwK0Yr96Mu/m+tobxdQp9QpmbW DSaQEQ6kelKOFSgl4GLZEbZoYGXxTIWM9QBcdFi0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Howells , Marc Dionne , linux-afs@lists.infradead.org, Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 484/602] rxrpc: Dont need barrier for ->tx_bottom and ->acks_hard_ack Date: Thu, 30 Jul 2026 16:14:36 +0200 Message-ID: <20260730141446.137299871@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141435.976815864@linuxfoundation.org> References: <20260730141435.976815864@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Howells [ Upstream commit 6396b48ac0a77165f9c2c40ab03d6c8188c89739 ] We don't need a barrier for the ->tx_bottom value (which indicates the lowest sequence still in the transmission queue) and the ->acks_hard_ack value (which tracks the DATA packets hard-ack'd by the latest ACK packet received and thus indicates which DATA packets can now be discarded) as the app thread doesn't use either value as a reference to memory to access. Rather, the app thread merely uses these as a guide to how much space is available in the transmission queue Change the code to use READ/WRITE_ONCE() instead. Also, change rxrpc_check_tx_space() to use the same value for tx_bottom throughout. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20241204074710.990092-18-dhowells@redhat.com Signed-off-by: Jakub Kicinski Stable-dep-of: e66f8f32f501 ("rxrpc: Fix socket notification race") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/rxrpc/sendmsg.c | 8 +++++--- net/rxrpc/txbuf.c | 4 ++-- 2 files changed, 7 insertions(+), 5 deletions(-) --- a/net/rxrpc/sendmsg.c +++ b/net/rxrpc/sendmsg.c @@ -93,9 +93,11 @@ no_wait: */ static bool rxrpc_check_tx_space(struct rxrpc_call *call, rxrpc_seq_t *_tx_win) { + rxrpc_seq_t tx_bottom = READ_ONCE(call->tx_bottom); + if (_tx_win) - *_tx_win = call->tx_bottom; - return call->tx_prepared - call->tx_bottom < 256; + *_tx_win = tx_bottom; + return call->tx_prepared - tx_bottom < 256; } /* @@ -137,7 +139,7 @@ static int rxrpc_wait_for_tx_window_wait rtt = 2; timeout = rtt; - tx_start = smp_load_acquire(&call->acks_hard_ack); + tx_start = READ_ONCE(call->acks_hard_ack); for (;;) { set_current_state(TASK_UNINTERRUPTIBLE); --- a/net/rxrpc/txbuf.c +++ b/net/rxrpc/txbuf.c @@ -216,14 +216,14 @@ void rxrpc_shrink_call_tx_buffer(struct while ((txb = list_first_entry_or_null(&call->tx_buffer, struct rxrpc_txbuf, call_link))) { - hard_ack = smp_load_acquire(&call->acks_hard_ack); + hard_ack = call->acks_hard_ack; if (before(hard_ack, txb->seq)) break; if (txb->seq != call->tx_bottom + 1) rxrpc_see_txbuf(txb, rxrpc_txbuf_see_out_of_step); ASSERTCMP(txb->seq, ==, call->tx_bottom + 1); - smp_store_release(&call->tx_bottom, call->tx_bottom + 1); + WRITE_ONCE(call->tx_bottom, call->tx_bottom + 1); list_del_rcu(&txb->call_link); trace_rxrpc_txqueue(call, rxrpc_txqueue_dequeue);