usb: typec: ucsi: Fix AB BA lock inversion

Lockdep reports an AB BA lock inversion between ucsi_init() and
ucsi_handle_connector_change():

AB order:

1. ucsi_init takes ucsi->ppm_lock (it runs with that locked for the
   duration of the function)
2. usci_init eventually end up calling ucsi_register_displayport,
   which takes ucsi_connector->lock

BA order:

1. ucsi_handle_connector_change work is started, takes ucsi_connector->lock
2. ucsi_handle_connector_change calls ucsi_send_command which takes
   ucsi->ppm_lock

The ppm_lock really only needs to be hold during 2 functions:
ucsi_reset_ppm() and ucsi_run_command().

This commit fixes the AB BA lock inversion by making ucsi_init drop the
ucsi->ppm_lock before it starts registering ports; and replacing any
ucsi_run_command() calls after this point with ucsi_send_command()
(which is a wrapper around run_command taking the lock while handling
the command).

Some of the replacing of ucsi_run_command with ucsi_send_command
in the helpers used during port registration also fixes a number of
code paths after registration which call ucsi_run_command() without
holding the ppm_lock:
1. ucsi_altmode_update_active() call in ucsi/displayport.c
2. ucsi_register_altmodes() call from ucsi_handle_connector_change()
   (through ucsi_partner_change())

Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200809141904.4317-2-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions