From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 413213E0C69 for ; Tue, 14 Apr 2026 12:05:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776168314; cv=none; b=hBEHNNa2Va6lvk25OmpJfAzKRRuTDEMfkWimHyfl5cCZZSKrZdJVVX02y9e8Ck/m2GYyhwhpF3RCpUCF2L43HZiQ4/Vj1HnMv+6nND96g8p5OGkJi7PNAYZkFST6wOCbWJ0IDv25tFAUwQKljIak+xeXdBKwRGgIkbT5Dx1QcVw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776168314; c=relaxed/simple; bh=S469/39aj++J5wlplXdi+uQ2FVXcE7M/B9i/gORyu+g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=avRLzTkO+hgOarNA/SvWy37it4DJk7tMeleiDIQ7YXD4WmcOIS+IOwPkhNT32KQLQqCR5WxsdmmPwYbLUnJ1f98DGrOr8Z8qP7vCDA/dpmTZLkCqUCNacNm3AEhBKLt31TTYKvI05J4K5Tg/e1wnidy7rs9UQ8bfqkrPVIGd6bk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EShSWokf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EShSWokf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49CF4C2BCB0; Tue, 14 Apr 2026 12:05:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776168314; bh=S469/39aj++J5wlplXdi+uQ2FVXcE7M/B9i/gORyu+g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EShSWokf8MAu/qQhWQ4f83KjQTU0E+JNdP84iXneFnHLUmD0EFy1y1YTtef3tTRCg U1DYqLjrjKUcz4GpaBhy+mNvJvpalDAUJC2+QsJDMqw3KVRf6EO1fq5zhQtGhRT6YN NOc1oi2jJHN2BjL4nZ9oqHdN1hYpV+1tx9TRGbSxYe6Z8dnN5DijprhuduTXTX46j+ xc/89eFIX5pWHiCPGXd6/wpXyEhnMITIdkXRmbv7r78X6QAymgdrjoLR62KnfMfm36 +GWFAwK+nST5S+lRRh2SAYnXrA/hTTmBr9X/iwebiPaVmGIjL/WaYfV3CFFED0velc gbknDaCryk8hg== From: Sasha Levin To: stable@vger.kernel.org Cc: David Howells , Marc Dionne , linux-afs@lists.infradead.org, Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6.y 1/2] rxrpc: Don't need barrier for ->tx_bottom and ->acks_hard_ack Date: Tue, 14 Apr 2026 08:05:10 -0400 Message-ID: <20260414120511.569429-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026041327-hydroxide-proofread-7f9e@gregkh> References: <2026041327-hydroxide-proofread-7f9e@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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: a44ce6aa2efb ("rxrpc: proc: size address buffers for %pISpc output") Signed-off-by: Sasha Levin --- net/rxrpc/sendmsg.c | 8 +++++--- net/rxrpc/txbuf.c | 4 ++-- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c index b9f2f12281b33..3feace069cd20 100644 --- a/net/rxrpc/sendmsg.c +++ b/net/rxrpc/sendmsg.c @@ -93,9 +93,11 @@ static int rxrpc_wait_to_be_connected(struct rxrpc_call *call, long *timeo) */ 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_waitall(struct rxrpc_sock *rx, 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); diff --git a/net/rxrpc/txbuf.c b/net/rxrpc/txbuf.c index d43be85123864..84d067fbc2fd1 100644 --- a/net/rxrpc/txbuf.c +++ b/net/rxrpc/txbuf.c @@ -112,14 +112,14 @@ void rxrpc_shrink_call_tx_buffer(struct rxrpc_call *call) 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); -- 2.53.0