On Mon, Aug 29, 2011 at 08:47:07PM +0200, Jan Kiszka wrote:

On 2011-08-29 17:42, Jan Kiszka wrote:

quoted

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

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