linux-kernel - Re: [PATCH v4 9/9] PCI/MSI: Introduce pci_auto_enable

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]

Date:	Mon, 23 Dec 2013 15:44:18 +0100
From:	Alexander Gordeev <agordeev@...hat.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
Cc:	linux-kernel@...r.kernel.org,
	Michael Ellerman <michael@...erman.id.au>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Tejun Heo <tj@...nel.org>,
	Ben Hutchings <bhutchings@...arflare.com>,
	David Laight <David.Laight@...LAB.COM>,
	Mark Lord <kernel@...rt.ca>, "H. Peter Anvin" <hpa@...or.com>,
	linux-pci@...r.kernel.org
Subject: Re: [PATCH v4 9/9] PCI/MSI: Introduce pci_auto_enable_msi*() family
 helpers

On Tue, Dec 17, 2013 at 05:30:02PM -0700, Bjorn Helgaas wrote:
> > +int pci_auto_enable_msi_range(struct pci_dev *dev, struct msix_entry *entries,
> > +			      int minvec, int maxvec)

[...]

> > +If this function returns a positive number it indicates at least the
> > +returned number of MSI interrupts have been successfully allocated (it may
> > +have allocated more in order to satisfy the power-of-two requirement).
> 
> I assume this means the return value may be larger than the "maxvec"
> requested, right?  And the driver is free to use all the vectors up to the
> return value, even those above maxvec, right?

No, the returned value may not be larger than the "maxvec" ever. This is just
paraphrasing the semantics of exisitng pci_enable_msi_block() interface - a
value written to MMC register might be larger than the returned value, but the
driver may not use the extra vectors it did not request.

-- 
Regards,
Alexander Gordeev
agordeev@...hat.com
--
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/