From: Tejun Heo <tj@kernel.org>
To: Alexander Gordeev <agordeev@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Michael Ellerman <michael@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Ben Hutchings <bhutchings@solarflare.com>,
David Laight <David.Laight@aculab.com>,
Mark Lord <kernel@start.ca>, "H. Peter Anvin" <hpa@zytor.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: [PATCH v4 9/9] PCI/MSI: Introduce pci_auto_enable_msi*() family helpers
Date: Thu, 19 Dec 2013 08:47:19 -0500 [thread overview]
Message-ID: <20131219134719.GA16994@htj.dyndns.org> (raw)
In-Reply-To: <20131219134244.GA32238@dhcp-26-207.brq.redhat.com>
Hello,
On Thu, Dec 19, 2013 at 02:42:45PM +0100, Alexander Gordeev wrote:
> I have troubles with this fallback logic. On each failed step we get an
> error and we do not know if this is indeed an error or an indication of
> insufficient MSI resources. Even -ENOSPC would not tell much, since it
> could be thrown from a lower level.
Well, it's not hard to define what -ENOSPC should mean.
> By contrast, with the tri-state return value we can distinguish and bail
> out on errors right away.
I kinda like that the available options are listed explicitly on the
caller side (even if it ends up being a loop). It decreases the
chance of the caller going "oh I didn't expect _that_" and generaly
makes things easier to follow.
> So the above is bit ungraceful for me. Combined with a possible waste in
> logs (if we're hitting the same error) it is quite enough for me to keep
> current the interfaces, at least for a time being.
FWIW, I like Bjorn's suggestion. Given that this is mostly corner
case thing, it isn't as important as the common ones but we might as
well while we're at it.
Thanks a lot for your work in the area! :)
--
tejun
next prev parent reply other threads:[~2013-12-19 13:47 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-16 8:34 [PATCH v4 0/9] PCI/MSI: Introduce pci_auto_enable_msi*() family helpers Alexander Gordeev
2013-12-16 8:34 ` [PATCH v4 1/9] PCI/MSI/s390: Fix single MSI only check Alexander Gordeev
2013-12-16 8:34 ` [PATCH v4 2/9] PCI/MSI/s390: Remove superfluous check of MSI type Alexander Gordeev
2013-12-16 8:34 ` [PATCH v4 3/9] PCI/MSI: Fix return value when populate_msi_sysfs() failed Alexander Gordeev
2013-12-16 8:34 ` [PATCH v4 4/9] PCI/MSI: Return -ENOSYS for unimplemented interfaces, not -1 Alexander Gordeev
2013-12-16 8:34 ` [PATCH v4 5/9] PCI/MSI: Make pci_enable_msi/msix() 'nvec' argument type as int Alexander Gordeev
2013-12-16 8:34 ` [PATCH v4 6/9] PCI/MSI: Factor out pci_get_msi_vec_count() interface Alexander Gordeev
2013-12-18 0:33 ` Bjorn Helgaas
2013-12-16 8:35 ` [PATCH v4 7/9] PCI/MSI: Get rid of pci_enable_msi_block_auto() interface Alexander Gordeev
2013-12-16 8:35 ` [PATCH v4 8/9] PCI/MSI: Introduce pci_get_msix_vec_count() interface Alexander Gordeev
2013-12-16 8:35 ` [PATCH v4 9/9] PCI/MSI: Introduce pci_auto_enable_msi*() family helpers Alexander Gordeev
2013-12-18 0:30 ` Bjorn Helgaas
2013-12-18 13:23 ` Alexander Gordeev
2013-12-18 18:58 ` Bjorn Helgaas
2013-12-19 13:42 ` Alexander Gordeev
2013-12-19 13:47 ` Tejun Heo [this message]
2013-12-19 21:37 ` Bjorn Helgaas
2013-12-20 9:04 ` Alexander Gordeev
2013-12-20 13:28 ` Tejun Heo
2013-12-20 10:28 ` Alexander Gordeev
2013-12-23 14:44 ` Alexander Gordeev
2013-12-23 17:19 ` Bjorn Helgaas
2013-12-19 22:30 ` [PATCH v4 0/9] " Bjorn Helgaas
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20131219134719.GA16994@htj.dyndns.org \
--to=tj@kernel.org \
--cc=David.Laight@aculab.com \
--cc=agordeev@redhat.com \
--cc=benh@kernel.crashing.org \
--cc=bhelgaas@google.com \
--cc=bhutchings@solarflare.com \
--cc=hpa@zytor.com \
--cc=kernel@start.ca \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=michael@ellerman.id.au \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.