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From: Luca Boccassi <bluca@debian.org>
To: Tiwei Bie <tiwei.bie@intel.com>
Cc: dev@dpdk.org, maxime.coquelin@redhat.com, zhihong.wang@intel.com,
	 bruce.richardson@intel.com,
	Brian Russell <brian.russell@intl.att.com>
Subject: Re: [dpdk-dev] [PATCH 2/2] virtio: fix PCI config err handling
Date: Wed, 15 Aug 2018 10:50:57 +0100
Message-ID: <1534326657.5764.11.camel@debian.org> (raw)
In-Reply-To: <20180815031144.GA7324@debian>

On Wed, 2018-08-15 at 11:11 +0800, Tiwei Bie wrote:
> On Tue, Aug 14, 2018 at 03:30:35PM +0100, Luca Boccassi wrote:
> > From: Brian Russell <brussell@brocade.com>
> > 
> > In virtio_read_caps, rte_pci_read_config returns the number of
> > bytes
> > read from PCI config or < 0 on error.
> > If less than the expected number of bytes are read then log the
> > failure and return rather than carrying on with garbage.
> 
> Is this a fix or an improvement?
> Or did you see anything broken without this patch?
> If so, we may need a fixes line and Cc stable.

It is a fix, as it was creating problems in production due to the
constant flux of errors in the logs.
But given patch 1/2 is effectively doing a small change in the BSD bus
API, and it's a requirement for 2/2, I don't think we can include it in
the stable releases unfortunately.

> > 
> > Signed-off-by: Brian Russell <brussell@brocade.com>
> > ---
> > 
> > Follow-up from:
> > http://mails.dpdk.org/archives/dev/2017-June/067278.html
> > https://patches.dpdk.org/patch/25056/
> > 
> >  drivers/net/virtio/virtio_pci.c | 12 +++++++-----
> >  1 file changed, 7 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/net/virtio/virtio_pci.c
> > b/drivers/net/virtio/virtio_pci.c
> > index 6bd22e54a6..a10698aed8 100644
> > --- a/drivers/net/virtio/virtio_pci.c
> > +++ b/drivers/net/virtio/virtio_pci.c
> > @@ -567,16 +567,18 @@ virtio_read_caps(struct rte_pci_device *dev,
> > struct virtio_hw *hw)
> >  	}
> >  
> >  	ret = rte_pci_read_config(dev, &pos, 1,
> > PCI_CAPABILITY_LIST);
> > -	if (ret < 0) {
> > -		PMD_INIT_LOG(DEBUG, "failed to read pci capability
> > list");
> > +	if (ret != 1) {
> > +		PMD_INIT_LOG(DEBUG,
> > +			     "failed to read pci capability list,
> > ret %d", ret);
> >  		return -1;
> >  	}
> >  
> >  	while (pos) {
> >  		ret = rte_pci_read_config(dev, &cap, sizeof(cap),
> > pos);
> > -		if (ret < 0) {
> > -			PMD_INIT_LOG(ERR,
> > -				"failed to read pci cap at pos:
> > %x", pos);
> > +		if (ret != sizeof(cap)) {
> > +			PMD_INIT_LOG(DEBUG,
> 
> Why change the log level to DEBUG?
> 
> Thanks

Beforehand reading less than the required amount of bytes caused
problems in the following code, so it warranted printing errors - but
now it will not go ahead without the right amount of data, so it's not
critical anymore to inform the user.
Main issue is, log will get very spammy with errors, and paying
customers don't like that :-)

-- 
Kind regards,
Luca Boccassi

  reply	other threads:[~2018-08-15  9:50 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-14 14:30 [dpdk-dev] [PATCH 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-14 14:30 ` [dpdk-dev] [PATCH 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-15  3:11   ` Tiwei Bie
2018-08-15  9:50     ` Luca Boccassi [this message]
2018-08-16  6:46       ` Tiwei Bie
2018-08-16 10:27         ` Luca Boccassi
2018-08-16 18:47 ` [dpdk-dev] [PATCH 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-16 18:47   ` [dpdk-dev] [PATCH 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-16 18:49     ` Luca Boccassi
2018-08-20  8:18       ` Tiwei Bie
2018-08-20 16:45         ` Luca Boccassi
2018-08-21  2:40           ` Tiwei Bie
2018-08-23 12:52             ` Luca Boccassi
2018-08-24  4:23               ` Tiwei Bie
2018-08-24 17:14                 ` Luca Boccassi
2018-08-20 16:44   ` [dpdk-dev] [PATCH v3 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-20 16:44     ` [dpdk-dev] [PATCH v3 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-24 17:14     ` [dpdk-dev] [PATCH v4 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-24 17:14       ` [dpdk-dev] [PATCH v4 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-27  5:29         ` Tiwei Bie
2018-08-27 16:52           ` Luca Boccassi
2018-08-28  6:47             ` Tiwei Bie
2018-08-27 16:52       ` [dpdk-dev] [PATCH v5 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-27 16:52         ` [dpdk-dev] [PATCH v5 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-28  6:43           ` Tiwei Bie
2018-08-28 10:14             ` Luca Boccassi
2018-08-28 10:12         ` [dpdk-dev] [PATCH v6 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-28 10:12           ` [dpdk-dev] [PATCH v6 2/2] net/virtio: fix PCI config err handling Luca Boccassi
2018-10-11 10:27             ` Thomas Monjalon
2018-10-11 10:53               ` Luca Boccassi
2018-10-11 13:01                 ` Tiwei Bie
2018-10-28 23:55                   ` Thomas Monjalon
2018-10-17  9:58           ` [dpdk-dev] [PATCH v6 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-10-17 10:57             ` Bruce Richardson

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