Re: [PATCH 06/14] scsi: qla2xxx: init/os: Remove in_interrupt().

Daniel Wagner
2020-11-30T13:27:16Z

On Thu, Nov 26, 2020 at 02:29:44PM +0100, Sebastian Andrzej Siewior wrote:
> From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
>
> qla83xx_wait_logic() is used to control the frequency of device IDC lock
> retries. If in_interrupt() is true, it does 20 loops of cpu_relax().
> Otherwise, it sleeps for 100ms and yields the CPU.
>
> While in_interrupt() is ill-defined and does not provide what the name
> suggests, it is not needed here: that qla83xx_wait_logic() is exclusively
> called by qla83xx_idc_lock() / unlock(), and they always run from
> process context. Below is an analysis of all the idc lock/unlock callers,
> in order of appearance:
>
> - qla_os.c:
> qla83xx_nic_core_unrecoverable_work(),
> qla83xx_idc_state_handler_work(),
> qla83xx_nic_core_reset_work(),
> qla83xx_service_idc_aen(), all workqueue context
>
> - qla_os.c: qla83xx_check_nic_core_fw_alive(), has msleep()
>
> - qla_os.c: qla83xx_set_drv_presence(), called once from
> qla2x00_abort_isp(), which is bound to process-context ->abort_isp()
> hook. It also invokes wait_for_completion_timeout() through the
> chain qla2x00_configure_hba() => qla24xx_link_initialize() =>
> qla2x00_mailbox_command().
>
> - qla_os.c: qla83xx_clear_drv_presence(), which is called from
> qla2x00_abort_isp() discussed above, and from qla2x00_remove_one()
> which is PCI process-context ->remove() hook.
>
> - qla_os.c: qla83xx_need_reset_handler(), has a one second msleep() in
> a loop.
>
> - qla_os.c: qla83xx_device_bootstrap(), called only by
> qla83xx_idc_state_handler(), which has multiple msleep()
> invocations.
>
> - qla_os.c: qla83xx_idc_state_handler(), multiple msleep()
> invocations.
>
> - qla_attr.c: qla2x00_sysfs_write_reset(), sysfs bin_attribute
> ->write() hook, process context
>
> - qla_init.c: qla83xx_nic_core_fw_load()
> => qla_init.c: qla2x00_initialize_adapter()
> => bound to isp_operations ->initialize_adapter() hook
> ** => qla_os.c: qla2x00_probe_one(), PCI ->probe() process ctx
>
> - qla_init.c: qla83xx_initiating_reset(), msleep() in a loop.
>
> - qla_init.c: qla83xx_nic_core_reset(), called by
> qla83xx_nic_core_reset_work(), workqueue context.
>
> Remove the in_interrupt() check, and thus replace the entirety of
> qla83xx_wait_logic() with an msleep(QLA83XX_WAIT_LOGIC_MS).
>
> Mark qla83xx_idc_lock() / unlock() with "Context: task, can sleep".
>
> Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Cc: Nilesh Javali <njavali@marvell.com>
> Cc: GR-QLogic-Storage-Upstream@marvell.com

Reviewed-by: Daniel Wagner <dwagner@suse.de>