On Sun, Jun 29, 2025 at 05:39:58PM -0600, Keith Busch wrote: > On Sun, Jun 29, 2025 at 01:28:08PM -0400, Michael S. Tsirkin wrote: > > On Sun, Jun 29, 2025 at 03:36:27PM +0200, Lukas Wunner wrote: > > > On Sat, Jun 28, 2025 at 02:58:49PM -0400, Michael S. Tsirkin wrote: > > > > > > 1/ The device_lock() will reintroduce the issues solved by 74ff8864cc84. > > > > I see. What other way is there to prevent dev->driver from going away, > > though? I guess I can add a new spinlock and take it both here and when > > dev->driver changes? Acceptable? > > You're already holding the pci_bus_sem here, so the final device 'put' > can't have been called yet, so the device is valid and thread safe in > this context. I think maintaining the desired lifetime of the > instantiated driver is just a matter of reference counting within your > driver. > > Just a thought on your patch, instead of introducing a new callback, you > could call the existing '->error_detected()' callback with the > previously set 'pci_channel_io_perm_failure' status. That would totally > work for nvme to kick its cleanup much quicker than the blk_mq timeout > handling we currently rely on for this scenario.
That's even easier, sure. However, Lukas raised the issue that pci_dev_set_disconnected must be fast, and drivers might do silly things in their callbacks. So, I was working on adding ability to schedule work on such an event, so prevent such misuse. At the same time, it's somewhat hard to abstract it all away in a driver independent manner, a callback is certainly easier. WDYT? -- MST
