---
- branch: MAIN
  date: Mon Mar 28 12:38:15 UTC 2022
  files:
  - new: '1.299'
    old: '1.298'
    path: src/sys/kern/subr_autoconf.c
    pathrev: src/sys/kern/subr_autoconf.c@1.299
    type: modified
  - new: '1.181'
    old: '1.180'
    path: src/sys/sys/device.h
    pathrev: src/sys/sys/device.h@1.181
    type: modified
  id: 20220328T123815Z.1ed38a7fcf732543a6cd413351899c7026590a87
  log: |
    autoconf(9): New function config_detach_commit.

    When a driver's .ca_detach function has committed to detaching -- it
    definitely won't back out with EBUSY, for instance -- it can call
    this to wake all pending calls to device_lookup_acquire and make them
    fail immediately.

    This is necessary to break a deadlock if the device_lookup_acquire
    calls happen inside I/O operations which the driver's .ca_detach
    function waits for the completion of -- without config_detach_commit,
    I/O operations would be stuck in device_lookup_acquire waiting for
    .ca_detach and .ca_detach would be stuck waiting for I/O operations
    to return.

    Most drivers won't need to call this: for autoconf drivers used the
    traditional way by devsw for userland device nodes, the .ca_detach
    routine uses vdevgone, and we will arrange to make vdevgone call
    config_detach_commit automagically in such drivers anyway.

    XXX kernel ABI change to struct device requires bump -- later change
    will make struct device opaque to ABI, but we're not there yet
  module: src
  subject: 'CVS commit: src/sys'
  unixtime: '1648471095'
  user: riastradh