From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>,
Brian King <brking@us.ibm.com>,
"James E.J. Bottomley" <JBottomley@parallels.com>,
"Hans J. Koch" <hjk@hansjkoch.de>,
Greg Kroah-Hartman <gregkh@suse.de>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: Broken pci_block_user_cfg_access interface
Date: Mon, 29 Aug 2011 22:18:58 +0300 [thread overview]
Message-ID: <20110829191858.GA9415@redhat.com> (raw)
In-Reply-To: <4E5BDEAB.5000405@siemens.com>
On Mon, Aug 29, 2011 at 08:47:07PM +0200, Jan Kiszka wrote:
> On 2011-08-29 17:42, Jan Kiszka wrote:
> > I still don't get what prevents converting ipr to allow plain mutex
> > synchronization. My vision is:
> > - push reset-on-error of ipr into workqueue (or threaded IRQ?)
>
> I'm starting to like your proposal: I had a look at ipr, but it turned
> out to be anything but trivial to convert that driver. It runs its
> complete state machine under spin_lock_irq, and the functions calling
> pci_block/unblock_user_cfg_access are deep inside this thing. I have no
> hardware to test whatever change, and I feel a bit uncomfortable asking
> Brian to redesign his driver that massively.
>
> So back to your idea: I would generalize pci_block_user_cfg_access to
> pci_block_cfg_access. It should fail when some other site already holds
> the access lock, but it should remain non-blocking - for the sake of ipr.
It would be easy to have blocking and non-blocking variants.
But
- I have no idea whether supporting sysfs config/reset access
while ipr is active makes any sense - I know we need it for uio.
- reset while uio handles interrupt needs to block, not fail I think
> We should still provide generic pci-2.3 IRQ masking services, but that
> could be done in a second step. I could have a look at this.
>
> Jan
>
> --
> Siemens AG, Corporate Technology, CT T DE IT 1
> Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2011-08-29 19:18 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-24 10:43 Broken pci_block_user_cfg_access interface Jan Kiszka
2011-08-24 15:02 ` Brian King
2011-08-25 9:19 ` Jan Kiszka
2011-08-25 9:40 ` Michael S. Tsirkin
2011-08-25 10:34 ` Jan Kiszka
2011-08-25 13:06 ` Brian King
2011-08-25 13:12 ` Brian King
2011-08-25 13:16 ` Jan Kiszka
2011-08-25 13:24 ` Brian King
2011-08-25 18:16 ` Michael S. Tsirkin
2011-08-25 13:02 ` Brian King
2011-08-25 13:06 ` Jan Kiszka
2011-08-25 18:19 ` Michael S. Tsirkin
2011-08-25 18:52 ` Jan Kiszka
2011-08-25 19:07 ` Michael S. Tsirkin
2011-08-25 19:26 ` Jan Kiszka
2011-08-29 15:05 ` Michael S. Tsirkin
2011-08-29 15:42 ` Jan Kiszka
2011-08-29 15:58 ` Michael S. Tsirkin
2011-08-29 16:14 ` Jan Kiszka
2011-08-29 16:23 ` Michael S. Tsirkin
2011-08-29 16:26 ` Jan Kiszka
2011-08-29 18:47 ` Jan Kiszka
2011-08-29 19:18 ` Michael S. Tsirkin [this message]
2011-08-30 16:30 ` Brian King
2011-08-30 18:01 ` Michael S. Tsirkin
2011-08-30 19:41 ` Brian King
2011-09-02 7:48 ` [RFC] pci: Rework config space blocking services Jan Kiszka
2011-09-06 7:00 ` Michael S. Tsirkin
2011-09-06 7:18 ` Jan Kiszka
2011-09-06 8:04 ` Michael S. Tsirkin
2011-09-06 8:27 ` Jan Kiszka
2011-09-06 8:47 ` Michael S. Tsirkin
2011-09-06 8:48 ` Jan Kiszka
2011-09-07 13:46 ` Brian King
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