On Thu, Nov 26, 2020 at 02:29:42PM +0100, Sebastian Andrzej Siewior wrote:
From: "Ahmed S. Darwish" <a.darwish@xxxxxxxxxxxxx>
qla82xx_idc_lock() spins on a certain hardware state until it's updated. At
the end of each spin, if in_interrupt() is true, it does 20 loops of
cpu_relax(). Otherwise, it yields the CPU.
While in_interrupt() is ill-defined and does not provide what the name
suggests, it is not needed here: qla82xx_idc_lock() is always called
from process context. Below is an analysis of its callers, in order of
appearance:
- qla_nx.c: qla82xx_device_bootstrap(), only called by
qla82xx_device_state_handler(), has multiple msleep()s.
- qla_nx.c: qla82xx_need_qsnt_handler(), has one second msleep()
- qla_nx.c: qla82xx_wait_for_state_change(), one second msleep()
- qla_nx.c: qla82xx_need_reset_handler(), can sleep up to 10 seconds
- qla_nx.c: qla82xx_device_state_handler(), has multiple msleep()s
- qla_nx.c: qla82xx_abort_isp(), if it's a qla82xx controller, calls
qla82xx_device_state_handler(), which sleeps. It's also bound to
isp_operations ->abort_isp() hook, where all the callers are in
process context.
- qla_nx.c: qla82xx_beacon_on(), bound to isp_operations ->beacon_on()
hook. That hook is only called once, in a mutex locked context,
from qla2x00_beacon_store().
- qla_nx.c: qla82xx_beacon_off(), bound to isp_operations
->beacon_off() hook. Like ->beacon_on(), it's only called once, in
a mutex locked context, from qla2x00_beacon_store().
- qla_nx.c: qla82xx_fw_dump(), calls qla2x00_wait_for_chip_reset(),
which has msleep() in a loop. It is bound to isp_operations
->fw_dump() hook. That hook *is* called from atomic context at
qla_isr.c by multiple interrupt handlers. Nonetheless, it's other
controllers interrupt handlers, and not the qla82xx.
qla82xx_msix_default() and qla82xx_msix_rsp_q() call
qla24xx_process_response_queue() which doesn't implement the firmware
dumping.
- qla_attr.c: qla2x00_sysfs_write_fw_dump(), and
qla2x00_sysfs_write_reset(), process-context sysfs ->write() hooks.
- qla_os.c: qla2x00_probe_one(). PCI ->probe(), process context.
- qla_os.c: qla2x00_clear_drv_active(), called solely from
qla2x00_remove_one(), which is PCI ->remove() hook, process context.
- qla_os.c: qla2x00_do_dpc(), kthread function, process context.
Remove the in_interrupt() check. Change qla82xx_idc_lock() specification
to a purely process-context function. Mark it with "Context: task, might
sleep".
Change qla82xx_idc_lock() implementation to sleep 100ms, instead of a
schedule(), for each spin. This is more deterministic, and it matches
the other qla models idc_lock() functions.
Signed-off-by: Ahmed S. Darwish <a.darwish@xxxxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Nilesh Javali <njavali@xxxxxxxxxxx>
Cc: <GR-QLogic-Storage-Upstream@xxxxxxxxxxx>
Reviewed-by: Daniel Wagner <dwagner@xxxxxxx>
