From: James Bottomley <James.Bottomley@SteelEye.com>
To: Jesse Barnes <jbarnes@engr.sgi.com>
Cc: Matthew Wilcox <willy@debian.org>,
Grant Grundler <grundler@parisc-linux.org>,
Andrew Vasquez <andrew.vasquez@qlogic.com>,
pj@sgi.com, SCSI Mailing List <linux-scsi@vger.kernel.org>,
mdr@cthulhu.engr.sgi.com, jeremy@cthulhu.engr.sgi.com,
djh@cthulhu.engr.sgi.com, Andrew Morton <akpm@osdl.org>
Subject: Re: SCSI QLA not working on latest *-mm SN2
Date: 21 Sep 2004 13:56:53 -0400 [thread overview]
Message-ID: <1095789421.2467.414.camel@mulgrave> (raw)
In-Reply-To: <200409211346.58267.jbarnes@engr.sgi.com>
On Tue, 2004-09-21 at 13:46, Jesse Barnes wrote:
> > What ioflush() call? There's no such thing in PCI; this is effectively
> > our problem. If there were a nice flush instruction we wouldn't have to
> > worry about reading from somewhere on the device. The problem is that
> > there's no a-priori way of knowing what read is safe to do, so there's
> > no generic way to extract a posting flush API.
>
> The one I just added with this patch. It takes a struct device and address
> arguments, the latter is supposed to be a safe register, like config space.
>
> I'm tying together the concepts of write posting and ordering intentionally,
> but I wonder if that's a good idea. On the one hand, we don't want to
> introduce *two* new driver APIs, but on the other, ensuring ordering and
> actually flushing writes out are two different things. Maybe we just need to
> tell people
Really, I don't think this is a good idea. If there were a way to
produce an api that was just ioflush(struct device *) then yes, since it
would reduce confusion. However, since all your API does is hide the
fact that you're doing a MMIO read then the proposed API provides no
relief from the fact that the driver writer needs to understand
posting...all it does is add one extra function for them to misuse or
get confused about.
James
next prev parent reply other threads:[~2004-09-21 17:58 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <B179AE41C1147041AA1121F44614F0B060EF48@AVEXCH02.qlogic.org>
[not found] ` <20040916121235.5e4f9c32.pj@sgi.com>
[not found] ` <1095362263.16326.12.camel@praka>
2004-09-16 19:56 ` SCSI QLA not working on latest *-mm SN2 Paul Jackson
2004-09-16 20:05 ` Jesse Barnes
2004-09-16 20:56 ` Andrew Vasquez
2004-09-16 21:09 ` Jesse Barnes
2004-09-16 21:40 ` Andrew Vasquez
2004-09-16 22:25 ` Andrew Morton
2004-09-16 22:29 ` Jesse Barnes
2004-09-17 17:21 ` Jesse Barnes
2004-09-18 6:10 ` Grant Grundler
2004-09-18 17:57 ` Documentation/io_ordering.txt is wrong Matthew Wilcox
2004-09-20 23:39 ` Jesse Barnes
2004-09-21 0:38 ` Jesse Barnes
2004-09-20 22:40 ` SCSI QLA not working on latest *-mm SN2 Jesse Barnes
2004-09-20 23:27 ` Grant Grundler
2004-09-21 0:09 ` Jesse Barnes
2004-09-21 5:46 ` Grant Grundler
2004-09-21 6:45 ` Jeremy Higdon
2004-09-21 13:29 ` Jesse Barnes
2004-09-21 13:25 ` Jesse Barnes
2004-09-21 15:13 ` Jesse Barnes
2004-09-21 15:41 ` James Bottomley
2004-09-21 15:58 ` Jesse Barnes
2004-09-21 16:01 ` Matthew Wilcox
2004-09-21 16:05 ` Jesse Barnes
2004-09-21 16:11 ` James Bottomley
2004-09-21 16:18 ` Jesse Barnes
2004-09-21 16:24 ` James Bottomley
2004-09-21 17:03 ` Jesse Barnes
2004-09-21 17:15 ` Matthew Wilcox
2004-09-21 17:24 ` Jesse Barnes
2004-09-21 17:20 ` James Bottomley
2004-09-21 17:46 ` Jesse Barnes
2004-09-21 17:56 ` James Bottomley [this message]
2004-09-21 18:09 ` Jesse Barnes
2004-09-21 19:06 ` Grant Grundler
2004-09-21 19:40 ` Jesse Barnes
2004-09-21 22:44 ` Grant Grundler
2004-09-21 21:03 ` Jeremy Higdon
2004-09-21 21:11 ` Matthew Wilcox
2004-09-21 21:43 ` Jeremy Higdon
2004-09-21 22:33 ` Jesse Barnes
2004-09-22 0:02 ` Matthew Wilcox
2004-09-22 1:16 ` Jeremy Higdon
2004-09-22 1:44 ` Grant Grundler
2004-09-22 2:58 ` Jeremy Higdon
2004-09-22 14:32 ` I/O write ordering Matthew Wilcox
2004-09-22 14:40 ` Benjamin Herrenschmidt
2004-09-22 14:50 ` Jesse Barnes
2004-09-22 14:47 ` James Bottomley
2004-09-22 14:51 ` Benjamin Herrenschmidt
2004-09-22 15:11 ` James Bottomley
2004-09-22 15:11 ` Benjamin Herrenschmidt
2004-09-22 15:22 ` James Bottomley
2004-09-22 15:28 ` Benjamin Herrenschmidt
2004-09-22 15:43 ` James Bottomley
2004-09-23 0:19 ` Benjamin Herrenschmidt
2004-09-23 1:58 ` Matthew Wilcox
2004-09-23 3:01 ` James Bottomley
2004-09-23 3:40 ` Benjamin Herrenschmidt
2004-09-23 4:26 ` Grant Grundler
2004-09-21 23:03 ` SCSI QLA not working on latest *-mm SN2 Guennadi Liakhovetski
2004-09-16 23:14 ` Jeremy Higdon
2004-09-16 20:11 ` Andrew Morton
2004-09-21 21:22 Andrew Vasquez
2004-09-21 21:44 ` Jeremy Higdon
2004-09-21 22:37 ` Jesse Barnes
2004-09-21 22:49 ` Jeremy Higdon
-- strict thread matches above, loose matches on Subject: below --
2004-09-21 20:50 Andrew Vasquez
2004-09-21 21:06 ` Jeremy Higdon
2004-09-21 22:36 ` Jesse Barnes
2004-09-21 22:39 ` Jeremy Higdon
2004-09-21 22:43 ` Jesse Barnes
2004-09-21 22:54 ` Jeremy Higdon
2004-09-21 23:17 ` Jesse Barnes
2004-09-22 21:33 ` Jesse Barnes
2004-09-21 17:33 Andrew Vasquez
2004-09-21 17:52 ` Jesse Barnes
2004-09-21 18:04 ` Matthew Wilcox
2004-09-21 18:59 ` Matthew Wilcox
2004-09-21 19:10 ` Jesse Barnes
2004-09-21 15:58 Andrew Vasquez
2004-09-21 16:07 ` Jesse Barnes
2004-09-21 16:25 ` Matthew Wilcox
2004-09-21 16:33 ` James Bottomley
2004-09-21 20:39 ` Jeremy Higdon
2004-09-21 20:43 ` Jeremy Higdon
2004-09-17 22:55 Andrew Vasquez
2004-09-17 23:10 ` Jesse Barnes
2004-09-17 23:55 ` James Bottomley
2004-09-18 1:15 ` Andrew Vasquez
2004-09-18 1:25 ` Matthew Wilcox
2004-09-18 1:24 ` Andrew Vasquez
2004-09-18 2:36 ` Jeremy Higdon
2004-09-18 19:12 ` James Bottomley
2004-09-15 22:51 Paul Jackson
2004-09-15 23:13 ` Andrew Morton
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