Subject: Re: [PATCH 1/1] pci: Block config access during BIST (resend)
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: brking@us.ibm.com
Cc: Andi Kleen <ak@muc.de>, paulus@samba.org, benh@kernel.crashing.org,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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References: <200501101449.j0AEnWYF020850@d03av01.boulder.ibm.com>
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On Llu, 2005-01-10 at 22:57, Brian King wrote:
> > For this I would add a semaphore or a lock bit to pci_dev.
> > Probably a simple flag is good enough that is checked by sysfs/proc
> > and return EBUSY when set. 
> 
> How about something like this... (only compile tested at this point)


User space does not expect to get dumped with -EBUSY randomly on PCI
accesses. Not a viable option in that form _but_ making them sleep would
work - even with a simple global wait queue
for the pci_unblock_.. path

ie add the following (oh and uninlined probably for compatcness)

static int pci_user_wait_access(struct pci_dev *pdev) {
	wait_event(&pci_ucfg_wait, dev->block_ucfg_access == 0);
}


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