From: manjugk@ti.com (G, Manjunath Kondaiah)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/5] drivercore: add new error value for deferred probe
Date: Wed, 12 Oct 2011 11:48:23 +0530 [thread overview]
Message-ID: <20111012061823.GB2080@manju-desktop> (raw)
In-Reply-To: <20111010010656.GA16537@kroah.com>
On Sun, Oct 09, 2011 at 06:06:56PM -0700, Greg KH wrote:
> On Sun, Oct 09, 2011 at 04:59:31PM -0600, Grant Likely wrote:
> > On Fri, Oct 7, 2011 at 6:12 PM, Greg KH <greg@kroah.com> wrote:
> > > On Fri, Oct 07, 2011 at 07:28:33PM -0400, Valdis.Kletnieks at vt.edu wrote:
> > >> On Fri, 07 Oct 2011 16:12:45 MDT, Grant Likely said:
> > >> > On Fri, Oct 7, 2011 at 12:43 AM, Greg KH <greg@kroah.com> wrote:
> > >> > > On Fri, Oct 07, 2011 at 10:33:06AM +0500, G, Manjunath Kondaiah wrote:
> > >>
> > >> > >> +#define EPROBE_DEFER 517 ? ? /* restart probe again after some time */
> > >> > >
> > >> > > Can we really do this?
> > >>
> > >> > According to Arnd, yes this is okay.
> > >>
> > >> > > ?Isn't this some user/kernel api here?
> > >>
> > >> > > What's wrong with just "overloading" on top of an existing error code?
> > >> > > Surely one of the other 516 types could be used here, right?
> > >>
> > >> > overloading makes it really hard to find the users at a later date.
> > >>
> > >> Would proposing '#define EPROBE_DEFER EAGAIN' be acceptable to everybody? That
> > >> would allow overloading EAGAIN, but still make it easy to tell the usages apart
> > >> if we need to separate them later...
> > >
> > > Yes, please do that, it is what USB does for it's internal error code
> > > handling.
> >
> > Really? When we've only currently used approximately 2^9 of a 2^31
> > numberspace? I'm fine with making sure that the number doesn't show
> > up in the userspace headers, but it makes no sense to overload the
> > #defines. Particularly so in this case where it isn't feasible to
> > audit every driver to figure out what probe might possibly return. It
> > is well within the realm of possibility that existing drivers are
> > already returning -EAGAIN.
>
> I doubt they are, but you are right, it's really hard to tell.
>
> > Besides; linux/errno.h *already* has linux-internal error codes that
> > do not get exported out to userspace. There is an #ifdef __KERNEL__
> > block around ERESTARTSYS through EIOCBRETRY which is filtered out when
> > exporting headers. I can't see any possible reason why we wouldn't
> > add Linux internal error codes here.
>
> As long as it stays internal, that's fine, I was worried that this would
> be exported to userspace.
>
> Alan, still object to this?
I hope no one has objections to use EPROBE_DEFER
-M
next prev parent reply other threads:[~2011-10-12 6:18 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1317963790-29426-1-git-send-email-manjugk@ti.com>
[not found] ` <1317963790-29426-2-git-send-email-manjugk@ti.com>
2011-10-07 6:43 ` [PATCH 1/5] drivercore: add new error value for deferred probe Greg KH
2011-10-07 10:00 ` Mark Brown
2011-10-07 22:12 ` Grant Likely
2011-10-07 23:28 ` Valdis.Kletnieks at vt.edu
2011-10-08 0:12 ` Greg KH
2011-10-09 22:59 ` Grant Likely
2011-10-10 1:06 ` Greg KH
2011-10-12 6:18 ` G, Manjunath Kondaiah [this message]
2011-10-13 4:10 ` Grant Likely
[not found] ` <1317963790-29426-3-git-send-email-manjugk@ti.com>
2011-10-07 6:49 ` [PATCH 2/5] drivercore: Add driver probe deferral mechanism Greg KH
2011-10-07 20:57 ` Josh Triplett
2011-10-07 21:23 ` Greg KH
2011-10-08 4:03 ` Josh Triplett
2011-10-08 15:55 ` Greg KH
2011-10-08 18:18 ` Josh Triplett
2011-10-10 17:37 ` Andrei Warkentin
2011-10-11 12:29 ` Ming Lei
2011-10-13 4:09 ` Grant Likely
2011-10-13 14:18 ` Ming Lei
2011-10-13 14:31 ` Alan Stern
2011-10-13 15:21 ` Ming Lei
2011-10-13 16:04 ` Alan Stern
2011-10-14 0:13 ` Ming Lei
2011-10-13 17:15 ` Grant Likely
2011-10-13 18:16 ` Alan Stern
2011-10-13 18:28 ` Grant Likely
2011-10-14 15:39 ` Alan Stern
2011-10-14 16:17 ` Grant Likely
2011-10-14 16:33 ` Alan Stern
2011-10-14 17:20 ` Grant Likely
2011-10-14 17:33 ` Alan Stern
2011-10-14 18:25 ` Grant Likely
2011-10-14 18:39 ` Alan Stern
2011-10-14 19:07 ` Grant Likely
2011-10-14 18:56 ` David Daney
2011-10-14 19:03 ` Grant Likely
2011-10-14 19:09 ` David Daney
2011-10-14 15:37 ` Alan Stern
2011-10-12 7:04 ` G, Manjunath Kondaiah
2011-10-07 21:28 ` Grant Likely
2011-10-07 6:50 ` [PATCH 0/5] Driver Probe Deferral Mechanism Greg KH
2011-10-07 7:37 ` G, Manjunath Kondaiah
[not found] ` <1317963790-29426-5-git-send-email-manjugk@ti.com>
2011-10-07 10:06 ` [PATCH 4/5] gpiolib: handle deferral probe error Alan Cox
2011-10-07 22:09 ` Grant Likely
2011-10-12 6:14 ` G, Manjunath Kondaiah
2011-10-13 4:12 ` Grant Likely
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