linux-kernel - Re: [PATCH v2 2/6] PCI/MSI: Factor out pci_get_msi

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAOS58YOZ4u7po=wb-v4Ua=oBiaKG==S1LMT70SdGEcNfAOVcOQ@mail.gmail.com>
Date:	Thu, 26 Sep 2013 10:42:10 -0400
From:	Tejun Heo <tj@...nel.org>
To:	Alexander Gordeev <agordeev@...hat.com>
Cc:	Bjorn Helgaas <bhelgaas@...gle.com>,
	Michael Ellerman <michael@...erman.id.au>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"linux-ide@...r.kernel.org" <linux-ide@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>, Joerg Roedel <joro@...tes.org>,
	Jan Beulich <JBeulich@...e.com>, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v2 2/6] PCI/MSI: Factor out pci_get_msi_cap() interface

Hello,

On Thu, Sep 26, 2013 at 10:39 AM, Alexander Gordeev <agordeev@...hat.com> wrote:
> I can imagine a scenario where the first device probes in, requests its

Well, we can imagine a lot of thing but usually have to draw the line somewhere.

> optimal number, acquires that number and exhausts MSIs in pSeries firmware.
> The next few devices possibly end up with single MSI, since no MSIs left
> to satisfy their optimal numbers. If one of those single-MSI'ed devices
> happened to be a high-performance HBA hitting a degraded performance that
> alone would force (IBM) to introduce the quotas. Now, if the same/another
> device happened does not support the legacy interrupt mode and no MSI
> resources have left in the platform firmware at all...

If that happens, that's just the platform code being dumb. Quota is
there to prevent that from happening, right? Let's please do something
simple and worry about problems if they actually exist.

Thanks.

-- 
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/