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From: Stephen Hemminger <stephen@networkplumber.org>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: Andrew Rybchenko <arybchenko@solarflare.com>, dev@dpdk.org
Subject: Re: [PATCH v5 00/15] common ethdev linkstatus functions
Date: Wed, 17 Jan 2018 08:05:55 -0800	[thread overview]
Message-ID: <20180117080555.5afd8c78@xeon-e3> (raw)
In-Reply-To: <27f327e5-5632-69cc-feaa-10cf9384a701@intel.com>

On Wed, 17 Jan 2018 14:32:17 +0000
Ferruh Yigit <ferruh.yigit@intel.com> wrote:

> On 1/17/2018 7:56 AM, Andrew Rybchenko wrote:
> > On 01/16/2018 09:37 PM, Stephen Hemminger wrote:  
> >> While reviewing drivers, noticed a lot of unnecessary
> >> duplication of code in drivers for handling the eth_dev link status
> >> information. While consolidating this, it also became obvious that
> >> some drivers behave differently for no good reason.
> >>
> >> It also was a good chance to introduce atomic exchange primitives
> >> in EAL because there are other places using cmpset where not
> >> necessary (such as bonding).
> >>
> >> Mostly only compile tested only, don't have all of the hardware
> >> available (except ixgbe and virtio) to test.
> >>
> >> Note: the eth_dev_link_update function return value is inconsistent
> >> across drivers. Should be changed to be void.  
> > 
> > I would say "link_update" callback return value is inconsistent across
> > drivers. I'm not sure which direction is right here: make it consistent
> > or make it void. Also any changes in link information could be
> > important. As I understand it should not happen without up/down,
> > but bugs with loss of intermediate transitions are definitely possible.
> > So, notifying about any changes in link information is definitely safer.
> > May be not now.  
> 
> Again, why not return previous link status, it is simple enough to prevent
> inconsistent usage.
> 
> rte_eth_link_get() already discards the return value, so won't be a problem there.
> 
> For the cases PMD would like know about link changes, they will need to
> implement almost same link_update function with a return value, so why not use
> existing link_update function?
> 
> Like been in virtio, link_update() used in interrupt handler, and calls a
> callback process if status changes. When link_update() return status changed to
> void, I guess they will need to implement another version of the link_update
> with return and use it.

The interrupt and non-interrupt model are different.
Also the driver internally may want to do something different, this is about
the return value for dev_ops->link_update.  The code in rte_eth_dev never
used the return value. The bonding driver was expecting it to work but it
doesn't. Anyway drivers shouldn't in general be directly calling other
devices eth_dev_ops

  reply	other threads:[~2018-01-17 16:05 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-16 18:37 [PATCH v5 00/15] common ethdev linkstatus functions Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 01/15] eal: introduce atomic exchange operation Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 02/15] ethdev: add linkstatus get/set helper functions Stephen Hemminger
2018-01-17  7:49   ` Andrew Rybchenko
2018-01-16 18:37 ` [PATCH v5 03/15] net/virtio: use eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 04/15] net/vmxnet3: use rte_eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 05/15] net/dpaa2: " Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 06/15] net/nfp: use rte_eth_linkstatus functions Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 07/15] net/e1000: use rte_eth_linkstatus helpers Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 08/15] net/ixgbe: use rte_eth_linkstatus functions Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 09/15] net/sfc: use new " Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 10/15] net/i40e: use " Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 11/15] net/liquidio: use rte_eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 12/15] net/thunderx: " Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 13/15] net/szedata: use _rte_eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 14/15] net/octeontx: use rte_eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [PATCH v5 15/15] net/enic: " Stephen Hemminger
2018-01-17  5:19 ` [PATCH v5 00/15] common ethdev linkstatus functions Shreyansh Jain
2018-01-17  7:56 ` Andrew Rybchenko
2018-01-17 14:32   ` Ferruh Yigit
2018-01-17 16:05     ` Stephen Hemminger [this message]
2018-01-17 16:18       ` Ferruh Yigit
2018-01-19 16:35         ` Ferruh Yigit
2018-01-21 18:35           ` Ferruh Yigit
2018-01-21 18:59 ` [PATCH v6 01/14] eal: introduce atomic exchange operation Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 02/14] ethdev: add linkstatus get/set helper functions Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 03/14] net/virtio: use ethdev linkstatus " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 04/14] net/vmxnet3: " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 05/14] net/dpaa2: " Ferruh Yigit
2018-01-22 12:28     ` Shreyansh Jain
2018-01-21 18:59   ` [PATCH v6 06/14] net/nfp: " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 07/14] net/e1000: " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 08/14] net/ixgbe: " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 09/14] net/i40e: " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 10/14] net/liquidio: " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 11/14] net/thunderx: " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 12/14] net/szedata2: " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 13/14] net/octeontx: " Ferruh Yigit
2018-01-21 18:59   ` [PATCH v6 14/14] net/enic: " Ferruh Yigit
2018-01-21 19:25   ` [PATCH v6 01/14] eal: introduce atomic exchange operation Ferruh Yigit
2018-01-21 23:50     ` Thomas Monjalon
2018-01-22 16:56       ` Stephen Hemminger
2018-01-22 21:03         ` Thomas Monjalon
2018-01-22 21:48           ` Stephen Hemminger
2018-01-22 22:09             ` Thomas Monjalon

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