From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>,
Daniel De Graaf <dgdegra@tycho.nsa.gov>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
"Keir (Xen.org)" <keir@xen.org>,
"jeremy@goop.org" <jeremy@goop.org>
Subject: Re: Re: [PATCH 1/2] xen/event: Add reference counting to event channel
Date: Tue, 25 Oct 2011 15:09:44 -0400 [thread overview]
Message-ID: <20111025190944.GF10062@phenom.dumpdata.com> (raw)
In-Reply-To: <1319530635.3385.215.camel@zakaz.uk.xensource.com>
On Tue, Oct 25, 2011 at 09:17:15AM +0100, Ian Campbell wrote:
> On Mon, 2011-10-24 at 21:22 +0100, Konrad Rzeszutek Wilk wrote:
> >
> > > +void evtchn_put(unsigned int evtchn)
> >
> > The decleration for 'evtchn' is 'unsigned short' so that can be
> > used instead of 'unsigned int'.
>
> I think I nearly made the same comment but then I looked at
> drivers/xen/events.c and found that it uses "unsigned", "unsigned
> short", "unsigned int" and "int" fairly interchangeably. The externally
> visible API (i.e. include/xen/events.h) tends to stick to just "unsigned
> int" or "int".
>
> The problem with the short types is that they don't leave room for an
> error indication, which is why on the Xen tools (libxc) side we have his
> piece of minor ugliness:
> typedef int evtchn_port_or_error_t;
>
> The actual hypercall interface uses "typedef uint32_t evtchn_port_t" but
> AIUI real evtchn values are guaranteed to fit in 31 bits.
Oh fun! So we actually have a bug with 'unsigned short' cutting it down
from 2^31 to 2^16!
next prev parent reply other threads:[~2011-10-25 19:09 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-16 21:14 [PATCH 0/2] Add reference counting to grant notify ioctls Daniel De Graaf
2011-09-16 21:14 ` [PATCH 1/2] xen/event: Add reference counting to event channel Daniel De Graaf
2011-09-17 4:50 ` Jeremy Fitzhardinge
2011-09-17 6:11 ` Keir Fraser
2011-09-19 15:50 ` Daniel De Graaf
2011-09-19 16:22 ` Jeremy Fitzhardinge
2011-09-19 17:53 ` Daniel De Graaf
2011-09-16 21:14 ` [PATCH 2/2] xen/gnt{dev, alloc}: reserve event channels for notify Daniel De Graaf
2011-10-18 21:04 ` [PATCH v2 0/2] Add reference counting to grant notify ioctls Daniel De Graaf
2011-10-18 21:04 ` [PATCH 1/2] xen/event: Add reference counting to event channel Daniel De Graaf
2011-10-19 9:20 ` Ian Campbell
2011-10-24 20:22 ` Konrad Rzeszutek Wilk
2011-10-24 22:20 ` Daniel De Graaf
2011-10-25 19:05 ` Konrad Rzeszutek Wilk
2011-10-25 8:17 ` Ian Campbell
2011-10-25 19:09 ` Konrad Rzeszutek Wilk [this message]
2011-10-25 20:44 ` Ian Campbell
2011-10-18 21:04 ` [PATCH 2/2] xen/gnt{dev, alloc}: reserve event channels for notify Daniel De Graaf
2011-10-19 9:24 ` Ian Campbell
2011-10-19 14:23 ` Daniel De Graaf
2011-10-19 14:45 ` [PATCH 2/2] xen/gnt{dev,alloc}: " Ian Campbell
2011-10-24 20:57 ` [PATCH 2/2] xen/gnt{dev, alloc}: " Konrad Rzeszutek Wilk
2011-10-24 22:01 ` Daniel De Graaf
2011-10-25 19:02 ` Konrad Rzeszutek Wilk
2011-10-25 19:41 ` Daniel De Graaf
2011-10-25 19:51 ` Konrad Rzeszutek Wilk
2011-10-25 20:27 ` Ian Campbell
2011-10-25 20:42 ` Daniel De Graaf
2011-10-25 20:50 ` Ian Campbell
2011-10-25 21:07 ` Daniel De Graaf
2011-10-26 15:47 ` [PATCH v3 0/3] Add reference counting to grant notify ioctls Daniel De Graaf
2011-10-26 15:47 ` [PATCH 1/3] xen/event: Add reference counting to event channels Daniel De Graaf
2011-10-26 16:51 ` Ian Campbell
2011-10-26 16:57 ` Ian Campbell
2011-10-26 17:28 ` Daniel De Graaf
2011-10-27 9:03 ` Ian Campbell
2011-10-26 18:42 ` [PATCH 1/3 v3.2] " Daniel De Graaf
2011-10-26 15:47 ` [PATCH 2/3] xen/gntalloc: Change gref_lock to a mutex Daniel De Graaf
2011-10-26 15:47 ` [PATCH 3/3] xen/gnt{dev, alloc}: reserve event channels for notify Daniel De Graaf
2011-10-27 21:58 ` [PATCH v4 0/3] Add reference counting to grant notify ioctls Daniel De Graaf
2011-10-27 21:58 ` [PATCH 1/3] xen/event: Add reference counting to event channels Daniel De Graaf
2011-10-27 21:58 ` [PATCH 2/3] xen/gntalloc: Change gref_lock to a mutex Daniel De Graaf
2011-10-27 21:58 ` [PATCH 3/3] xen/gnt{dev, alloc}: reserve event channels for notify Daniel De Graaf
2011-11-11 20:33 ` [PATCH v4 0/3] Add reference counting to grant notify ioctls Konrad Rzeszutek Wilk
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