From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pz2-f12.google.com (mail-pz2-f12.google.com [74.125.228.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D8E9A366051 for ; Sat, 19 Sep 2026 00:54:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.228.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789779281; cv=none; b=fTtQXLw35uIZB2/edziukEbDToRQxOBPwnVkvMzccbwhBvFREzs1lAQWeq/xSOQq2kndZcg3k4r6JdrV6/oWyQ9aaKXeiEON/7IbvH9HrGCiyBh5HfV/6VpumeWHh3Wa61ms1NQER6x4etLOQh4l5p4AGXkJg5fgMGp7ZVIkMsY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789779281; c=relaxed/simple; bh=QOhBEfG4yrhp+FTxVrBTMzSlWRARVPYUlGxnIlFF3kQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VAomg6ckhDVVxdZbcb6SSAwMCem3x9Hfq03UkVzkpPFuHRZOW+yoBLPuLEqqrterRdJdO9mflAnGIqHmP4WWMXDsgcmPTbYODcdQR40qD3VU8X8y4fh0BdMp6b/kOhU434DWTGkDZZAVjCuUzqOX0gZKF3foFB5mLNEPmAkDvCE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dama.to; spf=none smtp.mailfrom=dama.to; dkim=pass (2048-bit key) header.d=dama-to.20251104.gappssmtp.com header.i=@dama-to.20251104.gappssmtp.com header.b=qDiih7Ly; arc=none smtp.client-ip=74.125.228.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dama.to Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=dama.to Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=dama-to.20251104.gappssmtp.com header.i=@dama-to.20251104.gappssmtp.com header.b="qDiih7Ly" Received: by mail-pz2-f12.google.com with SMTP id 41be03b00d2f7-cc4bdf8abaaso1067484a12.2 for ; Fri, 18 Sep 2026 17:54:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dama-to.20251104.gappssmtp.com; s=20251104; t=1789779276; x=1790384076; darn=lists.linux.dev; h=in-reply-to:content-disposition:content-type:mime-version :references:mail-followup-to:message-id:subject:cc:to:from:date:from :to:cc:subject:date:message-id:reply-to:content-type; bh=aS8vpLbCC+UV4B+QKFVqLQosffbfcP7BnnH9D7Kwu74=; b=qDiih7LyxG3nH8M1rUS+liNFBDz7bCrZBwDkRP7NcJHtyh+8LEhnor7A1V2a8ql+VS sUzUsGYJHceCaoRdecX2AD14zzDyx+chSHUMDTHFO7XkvEkzyUmfPDjZDkfmmxruXDsD dJnPj1k+yiqLW978LOeqO8gEZIP5pSyiYJZmJnl3S5BPcx8dRrDCXfX/CoQtuekfz0ML kg+wRxmwd/pYwP6fyUS2UlMgL4rRByRXo6TP0z0D6bdB01hYYqNHdGOqAzMamq0vcrUg cN20Wgmb5WIbAS0fp3pnvx+QDe21R15OhjTdOMYy4ZJzq3/zKArDY4ROiHOb1R3AO2s1 8gYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789779276; x=1790384076; h=in-reply-to:content-disposition:content-type:mime-version :references:mail-followup-to:message-id:subject:cc:to:from:date :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=aS8vpLbCC+UV4B+QKFVqLQosffbfcP7BnnH9D7Kwu74=; b=IEDkZYR93xhnLgh6UL/3sWwNGc9xjl7Kok0/87oJ1Cqg0wSRB2V3zwmUC3LZNVSwY8 ltMhSDdHUyVrXxqzD85+PPRjmkQSmbLHqhup++B23ydmr7RoNROhUNjapFyyi4OQEoKG p4MxDWggdFa8L0vZM1CfBlwTv1BQDmxYD+Uyc8ZlR6x304dd4cdogRY51S0kjXSwxQRY xWivsozAJdcug2/7zjznVS01cU8nwZ26VnsrEOZVfYFv3M3Ff62Bu9nWlTeRHepL2hHH zhDo+pv6IQBGIn/crHOIQmIblOzPg5umvnLTqLm8wSERxQa8TphXGquqDdpite0X4UGN nVOg== X-Forwarded-Encrypted: i=1; AKwUvBwdBhznMxDXk2KeO7DhE07ZaTQMsZgP9R22rTORivNMwf+AYsZuGm10sTj3wLbFitLtsc8=@lists.linux.dev X-Gm-Message-State: AFuF++l+i6tRPUq63aU0CuJ+cnx1LSNEC0PncYtszFVlZVgnGCfyH9eI VFBDC4JLR06qLWH6FC9r2YvOpWkocrT3oM4kyOBaFvOR+doblsr49EoNfHJvnRC0joY= X-Gm-Gg: AYBFou38USm5ln2ikIhzI6BB8LHBkOpnos8BdXkSZBe1EQ4t4NZEQWpvQ0FSrYTPtUr uwJv5OBHuj4MThXnWbzrIbxGsy9Ib+LhmWXKYY/i6dkw2PFTzDDkZ4BDrf5YzX/adECS9leV1Bp 6JzY1VIcjkc4aHL1MP8C1WNi9LDr6/cDtnUv0FIeMfvOPyv2ZWnPNEDpp1Uz+vrfBMHIGz4Mwc7 5u2vjx0rU324mXd82k14zrgZZbBbFHPuBDH6dRsG6Gk/pULlm29zRmCiB8aJHUgwvlS76uyAB/1 DWNL7DzhxPeVQHMSysO00gLzH9k8iHImvYUWM2N7oOaqmqnX8OHzmDealiq9FRCBAkWUk/4e/XC DZtQ1XiEDCGU3A/OC710R5HrS/haMDUXntAMgdpbetBwc8iOTslzp/Enkorj3yKakiwhTFkC9ja 0S6fEJyISTgSc3OT+uWxw73RouAc+VeO4LpIksTdwJvu3qhhawnN+b X-Received: by 2002:a17:90a:c089:b0:39e:6c68:c78c with SMTP id 98e67ed59e1d1-39e6c68ca3bmr1516708a91.66.1789779276128; Fri, 18 Sep 2026 17:54:36 -0700 (PDT) Received: from localhost ([2a03:2880:2ff:4e::]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-39e6c5b3932sm1706421a91.13.2026.09.18.17.54.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Sep 2026 17:54:35 -0700 (PDT) Date: Fri, 18 Sep 2026 17:54:34 -0700 From: Joe Damato To: Koichiro Den Cc: Jon Mason , Dave Jiang , Allen Hubbe , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , ntb@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v4 02/10] NTB: ntb_transport: Use little-endian shared fields Message-ID: Mail-Followup-To: Joe Damato , Koichiro Den , Jon Mason , Dave Jiang , Allen Hubbe , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , ntb@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260914084838.2158249-1-den@valinux.co.jp> <20260914084838.2158249-3-den@valinux.co.jp> Precedence: bulk X-Mailing-List: ntb@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260914084838.2158249-3-den@valinux.co.jp> On Mon, Sep 14, 2026 at 05:48:30PM +0900, Koichiro Den wrote: > ntb_transport writes payload headers and the RX ring tail with > iowrite32(), but reads peer-written copies from coherent memory as native > integers. The values are therefore byte-swapped when read on a big-endian > system. > > Mark the shared fields as __le32 and convert coherent-memory accesses > accordingly. Read hdr->ver and hdr->len once so their checks and later > uses see the same values. > > Fixes: 74465645cdb4 ("NTB: Fix Sparse Warnings") > Reported-by: Sashiko > Link: https://lore.kernel.org/r/20260815032932.151F11F000E9@smtp.kernel.org/ > Link: https://lore.kernel.org/r/20260818064951.7EA231F000E9@smtp.kernel.org/ > Reviewed-by: Dave Jiang > Signed-off-by: Koichiro Den > --- > Changes in v4: > - No changes. > > drivers/ntb/ntb_transport.c | 47 +++++++++++++++++++++---------------- > 1 file changed, 27 insertions(+), 20 deletions(-) > > diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c > index 74f4f8c1c7be..3f497a62673f 100644 > --- a/drivers/ntb/ntb_transport.c > +++ b/drivers/ntb/ntb_transport.c [...] > @@ -514,7 +514,8 @@ static int ntb_qp_debugfs_stats_show(struct seq_file *s, void *v) > seq_printf(s, "tx_err_no_buf - %llu\n", qp->tx_err_no_buf); > seq_printf(s, "tx_mw - \t0x%p\n", qp->tx_mw); > seq_printf(s, "tx_index (H) - \t%u\n", qp->tx_index); > - seq_printf(s, "RRI (T) - \t%u\n", qp->remote_rx_info->entry); > + seq_printf(s, "RRI (T) - \t%u\n", > + le32_to_cpu(qp->remote_rx_info->entry)); it looks like the code READ_ONCE's this field below.... is that needed here too? > seq_printf(s, "tx_max_entry - \t%u\n", qp->tx_max_entry); > seq_printf(s, "free tx - \t%u\n", ntb_transport_tx_free_entry(qp)); > seq_putc(s, '\n'); > @@ -633,7 +634,7 @@ static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt, > qp->rx_alloc_entry++; > } > > - qp->remote_rx_info->entry = qp->rx_max_entry - 1; > + qp->remote_rx_info->entry = cpu_to_le32(qp->rx_max_entry - 1); you read_once below, do you need a write_once too ? i wonder if the read_once / write_once with endian conversion can be wrapped up in a helper or something to simplify? not sure, it might introduce more code than really necessary. > /* setup the hdr offsets with 0's */ > for (i = 0; i < qp->rx_max_entry; i++) { > @@ -919,7 +920,7 @@ static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp) > { > ntb_qp_link_context_reset(qp); > if (qp->remote_rx_info) > - qp->remote_rx_info->entry = qp->rx_max_entry - 1; > + qp->remote_rx_info->entry = cpu_to_le32(qp->rx_max_entry - 1); same as above with the onces ? > } > > static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp) > @@ -1445,7 +1446,7 @@ static void ntb_complete_rxc(struct ntb_transport_qp *qp) > if (!(entry->flags & DESC_DONE_FLAG)) > break; > > - entry->rx_hdr->flags = 0; > + entry->rx_hdr->flags = cpu_to_le32(0); this looked weird to me but grep says this is a common idiom, so TIL cpu_to_le32(0) is a thing. [...] > @@ -2490,7 +2495,9 @@ EXPORT_SYMBOL_GPL(ntb_transport_max_size); > unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp) > { > unsigned int head = qp->tx_index; > - unsigned int tail = qp->remote_rx_info->entry; > + unsigned int tail; > + > + tail = le32_to_cpu(READ_ONCE(qp->remote_rx_info->entry)); see above re: read_once and write_once on this field... i didn't really try prototyping anything but seeing this repeated pattern makes me wonder if static inline u32 ntb_remote_rx_entry(blah) { return le32_to_cpu(READ_ONCE(....)); } would make the code clearer ... or less clear. not sure.