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From: Justin Lai <justinlai0215@realtek.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: "davem@davemloft.net" <davem@davemloft.net>,
	"edumazet@google.com" <edumazet@google.com>,
	"pabeni@redhat.com" <pabeni@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"andrew@lunn.ch" <andrew@lunn.ch>,
	"jiri@resnulli.us" <jiri@resnulli.us>,
	"horms@kernel.org" <horms@kernel.org>,
	"rkannoth@marvell.com" <rkannoth@marvell.com>,
	"Ping-Ke Shih" <pkshih@realtek.com>,
	Larry Chiu <larry.chiu@realtek.com>
Subject: RE: [PATCH net-next v20 07/13] rtase: Implement a function to receive packets
Date: Tue, 18 Jun 2024 03:40:34 +0000	[thread overview]
Message-ID: <5835ed19887d4b5fae93c54c1704fa2b@realtek.com> (raw)
In-Reply-To: <20240617080232.620a2452@kernel.org>

> On Mon, 17 Jun 2024 06:44:55 +0000 Justin Lai wrote:
> > > > +             /* make sure discriptor has been updated */
> > > > +             rmb();
> > >
> > > Barriers are between things. What is this barrier between?
> >
> > At the end of this do while loop, it fetches the next descriptor. This
> > barrier is mainly used between fetching the next descriptor and using
> > the next descriptor, to ensure that the content of the next descriptor
> > is completely fetched before using it.
> 
> What does it mean to "fetch the next descriptor"? The prefetch?
> Prefetches are not ordered at all.

Let me explain again, at the end of the do while loop in rx_handler, we
have changed the address pointed by desc to the next descriptor.
Therefore, the main purpose of this barrier is to ensure that both desc
and cur_rx have been updated to the next entry.

  reply	other threads:[~2024-06-18  3:41 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-07  8:43 [PATCH net-next v20 00/13] Add Realtek automotive PCIe driver Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 01/13] rtase: Add pci table supported in this module Justin Lai
2024-06-13  9:01   ` Markus Elfring
2024-06-17  8:14     ` Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 02/13] rtase: Implement the .ndo_open function Justin Lai
2024-06-13  7:50   ` Markus Elfring
2024-06-17  9:25     ` Justin Lai
2024-06-17 10:07       ` [v20 " Markus Elfring
2024-06-17 13:28         ` Justin Lai
2024-06-17 18:59           ` Simon Horman
2024-06-17 20:22             ` Markus Elfring
2024-06-18  7:51             ` Justin Lai
     [not found]             ` <202406181007.45IA7eWxA3305754@rtits1.realtek.com.tw>
2024-06-18 11:01               ` Justin Lai
2024-06-18 11:30                 ` Markus Elfring
2024-06-07  8:43 ` [PATCH net-next v20 03/13] rtase: Implement the rtase_down function Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 04/13] rtase: Implement the interrupt routine and rtase_poll Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 05/13] rtase: Implement hardware configuration function Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 06/13] rtase: Implement .ndo_start_xmit function Justin Lai
2024-06-07  9:03   ` Hariprasad Kelam
2024-06-12  4:35     ` Justin Lai
2024-06-12 10:36       ` Hariprasad Kelam
2024-06-13  3:38         ` Justin Lai
2024-06-13  7:24           ` Hariprasad Kelam
2024-06-07 15:54   ` Ratheesh Kannoth
2024-06-12  4:20     ` Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 07/13] rtase: Implement a function to receive packets Justin Lai
2024-06-13  0:43   ` Jakub Kicinski
2024-06-17  6:44     ` Justin Lai
2024-06-17 15:02       ` Jakub Kicinski
2024-06-18  3:40         ` Justin Lai [this message]
2024-06-07  8:43 ` [PATCH net-next v20 08/13] rtase: Implement net_device_ops Justin Lai
2024-06-13  0:39   ` Jakub Kicinski
2024-06-13  3:16     ` Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 09/13] rtase: Implement pci_driver suspend and resume function Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 10/13] rtase: Implement ethtool function Justin Lai
2024-06-13  0:35   ` Jakub Kicinski
2024-06-17  6:54     ` Justin Lai
2024-06-17 14:07       ` Andrew Lunn
2024-06-18  9:56         ` Justin Lai
2024-06-17 15:10       ` Jakub Kicinski
2024-06-18  7:28         ` Justin Lai
2024-06-18 14:24           ` Jakub Kicinski
2024-06-19  3:40             ` Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 11/13] rtase: Add a Makefile in the rtase folder Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 12/13] realtek: Update the Makefile and Kconfig in the realtek folder Justin Lai
2024-06-07  8:43 ` [PATCH net-next v20 13/13] MAINTAINERS: Add the rtase ethernet driver entry Justin Lai

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