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 AEF9E1CD15 for ; Fri, 28 Jun 2024 17:05:30 +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=1719594330; cv=none; b=lvPDfgnXD5iUdX+/YgEQHmoDKZfhhcqsnmrJQSDit+hK4EF021WmUXMOLO2dhWynqSFR2QhTrH5O/Lxnh6eG0tY1OM0kjEjnXET24LeQ0K7LTkC9T1tHdpZvy2807nJRS2bZfpbH9sZl2j3NiAtzOOIoRTJIrNxIML/bFULwkNI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719594330; c=relaxed/simple; bh=StuUw3n/zgx5e6jygzaHpp+0HYcc2lg+xKuy6s7PjNE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Y4eUhMXaItzPfZYsOlwlE5fVjbdzdz3ZTBTSObO+i3/fNWyguApEPV9auAMlHhyVKk9+o7gt7zz9FvjLdnzsbs6dChZXOp6vlS+5EvPeEpWEqiwW1kjkPH6UGwGoJ2PZ/4IU54e0kwQs8t4cwCSvVUl0XDfL0yZDS/w5CdOOSjY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DuwA0y0Z; 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="DuwA0y0Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56C86C32786; Fri, 28 Jun 2024 17:05:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719594330; bh=StuUw3n/zgx5e6jygzaHpp+0HYcc2lg+xKuy6s7PjNE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DuwA0y0ZhByRI+QXBFnU04u5CRRORhCHKGKTdxo+n4IAoqIYsadXybBJ3U1jdFL1P kshncFdVvVH7v0CKGA2Y/lLNNpT1W2HOc5xJxCUK/lPDBiHhIV9XtQMWPoM0/5tj+h CiSvInKwQUP3AMm55+JPHHlfDg/kkm1kkAyIt8T53QP6U71kMhizD96akSnFs6hf3Z 9ajiUf19zuNlVWf4nFeG4vY2bl4T3zQb8oH9rCCEtjhqLZDBM8Q/eufAjlBngOjOMZ FCXxJn3K+RHb2nyMboNcxDC6UIaxLIUFz70XeC4WuvvmP2O8lKJkjsUVGf+9rjIsOK Vbss2UGpP8cfw== Date: Fri, 28 Jun 2024 18:05:26 +0100 From: Simon Horman To: Michael Chan Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, pavan.chebbi@broadcom.com, andrew.gospodarek@broadcom.com, richardcochran@gmail.com Subject: Re: [PATCH net-next 09/10] bnxt_en: Increase the max total outstanding PTP TX packets to 4 Message-ID: <20240628170526.GL783093@kernel.org> References: <20240626164307.219568-1-michael.chan@broadcom.com> <20240626164307.219568-10-michael.chan@broadcom.com> <20240628170318.GK783093@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240628170318.GK783093@kernel.org> On Fri, Jun 28, 2024 at 06:03:18PM +0100, Simon Horman wrote: > On Wed, Jun 26, 2024 at 09:43:06AM -0700, Michael Chan wrote: > > From: Pavan Chebbi > > > > Start accepting up to 4 TX TS requests on BCM5750X (P5) chips. > > These PTP TX packets will be queued in the ptp->txts_req[] array > > waiting for the TX timestamp to complete. The entries in the > > array will be managed by a producer and consumer index. The > > producer index is updated under spinlock since multiple TX rings > > can try to send PTP packets at the same time. > > > > Signed-off-by: Pavan Chebbi > > Signed-off-by: Michael Chan > > ... > > > diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c > > index ed2bbdf6b25f..0867861c14bd 100644 > > --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c > > +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c > > @@ -457,8 +457,8 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) > > unsigned int length, pad = 0; > > u32 len, free_size, vlan_tag_flags, cfa_action, flags; > > struct bnxt_ptp_cfg *ptp = bp->ptp_cfg; > > - u16 prod, last_frag; > > struct pci_dev *pdev = bp->pdev; > > + u16 prod, last_frag, txts_prod; > > struct bnxt_tx_ring_info *txr; > > struct bnxt_sw_tx_bd *tx_buf; > > __le32 lflags = 0; > > @@ -526,11 +526,19 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) > > if (!bnxt_ptp_parse(skb, &seq_id, &hdr_off)) { > > if (vlan_tag_flags) > > hdr_off += VLAN_HLEN; > > - ptp->txts_req.tx_seqid = seq_id; > > - ptp->txts_req.tx_hdr_off = hdr_off; > > lflags |= cpu_to_le32(TX_BD_FLAGS_STAMP); > > tx_buf->is_ts_pkt = 1; > > skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS; > > + > > + spin_lock_bh(&ptp->ptp_tx_lock); > > + txts_prod = ptp->txts_prod; > > + ptp->txts_prod = NEXT_TXTS(txts_prod); > > + spin_unlock_bh(&ptp->ptp_tx_lock); > > + > > + ptp->txts_req[txts_prod].tx_seqid = seq_id; > > + ptp->txts_req[txts_prod].tx_hdr_off = hdr_off; > > + tx_buf->txts_prod = txts_prod; > > + > > } else { > > atomic_inc(&bp->ptp_cfg->tx_avail); > > } > > @@ -770,7 +778,9 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) > > tx_kick_pending: > > if (BNXT_TX_PTP_IS_SET(lflags)) { > > atomic64_inc(&bp->ptp_cfg->stats.ts_err); > > - atomic_inc(&bp->ptp_cfg->tx_avail); > > + if (!(bp->fw_cap & BNXT_FW_CAP_TX_TS_CMP)) > > + /* set SKB to err so PTP worker will clean up */ > > + ptp->txts_req[txts_prod].tx_skb = ERR_PTR(-EIO); > > Hi Michael > > Sparse complains that previously it was assumed that ptp could be NULL, > but here it is accessed without checking for that. > > Perhaps it can't occur, but my brief check leads me to think it might. > > On line 488 there is the following: > > if (unlikely(ipv6_hopopt_jumbo_remove(skb))) > goto tx_free; > > Which will lead to the code in the hunk above. > > Then on line 513 there is a check for ptp being NULL: > > > if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) && ptp && > ptp->tx_tstamp_en) { > > And ptp is not set between lines 488 and 513. > > > Sparse also complains that txts_prod may be used uninitaialised. > This also seems to be a valid concern as it does seem to be the case > on line 488. > > > } > > if (txr->kick_pending) > > bnxt_txr_db_kick(bp, txr, txr->tx_prod); > > ... Sorry, in my previous email I mentioned Sparse. But I should have said Smatch.