From: Ahmed S. Darwish a.darwish@linutronix.de
[ Upstream commit 885ab3b8926fdf9cdd7163dfad99deb9b0662b39 ]
Use the new libsas event notifiers API, which requires callers to explicitly pass the gfp_t memory allocation flags.
sas_notify_phy_event() is exclusively called by isci_port_link_down(). Below is the context analysis for all of its call chains:
port.c: port_timeout(), atomic, timer callback (*) spin_lock_irqsave(isci_host::scic_lock, ) -> port_state_machine_change(..., SCI_PORT_FAILED) -> enter SCI port state: *SCI_PORT_FAILED* -> sci_port_failed_state_enter() -> isci_port_hard_reset_complete() -> isci_port_link_down()
port.c: isci_port_perform_hard_reset() spin_lock_irqsave(isci_host::scic_lock, ) -> port.c: sci_port_hard_reset(), atomic (*) -> phy.c: sci_phy_reset() -> sci_change_state(SCI_PHY_RESETTING) -> enter SCI PHY state: *SCI_PHY_RESETTING* -> sci_phy_resetting_state_enter() -> port.c: sci_port_deactivate_phy() -> isci_port_link_down()
port.c: enter SCI port state: *SCI_PORT_READY* # Cont. from [1] -> sci_port_ready_state_enter() -> isci_port_hard_reset_complete() -> isci_port_link_down()
phy.c: enter SCI state: *SCI_PHY_STOPPED* # Cont. from [2] -> sci_phy_stopped_state_enter() -> host.c: sci_controller_link_down() -> ->link_down_handler() == port_config.c: sci_apc_agent_link_down() -> port.c: sci_port_remove_phy() -> sci_port_deactivate_phy() -> isci_port_link_down() == port_config.c: sci_mpc_agent_link_down() -> port.c: sci_port_link_down() -> sci_port_deactivate_phy() -> isci_port_link_down()
phy.c: enter SCI state: *SCI_PHY_STARTING* # Cont. from [3] -> sci_phy_starting_state_enter() -> host.c: sci_controller_link_down() -> ->link_down_handler() == port_config.c: sci_apc_agent_link_down() -> port.c: sci_port_remove_phy() -> isci_port_link_down() == port_config.c: sci_mpc_agent_link_down() -> port.c: sci_port_link_down() -> sci_port_deactivate_phy() -> isci_port_link_down()
[1] Call chains for 'enter SCI port state: *SCI_PORT_READY*' ------------------------------------------------------------
host.c: isci_host_init() (@) spin_lock_irq(isci_host::scic_lock) -> sci_controller_initialize(), atomic (*) -> port_config.c: sci_port_configuration_agent_initialize() -> sci_mpc_agent_validate_phy_configuration() -> port.c: sci_port_add_phy() -> sci_port_general_link_up_handler() -> port_state_machine_change(, SCI_PORT_READY) -> enter port state *SCI_PORT_READY*
host.c: isci_host_start() (@) spin_lock_irq(isci_host::scic_lock) -> host.c: sci_controller_start(), atomic (*) -> host.c: sci_port_start() -> port.c: port_state_machine_change(, SCI_PORT_READY) -> enter port state *SCI_PORT_READY*
port_config.c: apc_agent_timeout(), atomic, timer callback (*) -> sci_apc_agent_configure_ports() -> port.c: sci_port_add_phy() -> sci_port_general_link_up_handler() -> port_state_machine_change(, SCI_PORT_READY) -> enter port state *SCI_PORT_READY*
port_config.c: mpc_agent_timeout(), atomic, timer callback (*) spin_lock_irqsave(isci_host::scic_lock, ) -> ->link_up_handler() == port.c: sci_apc_agent_link_up() -> sci_port_general_link_up_handler() -> port_state_machine_change(, SCI_PORT_READY) -> enter port state *SCI_PORT_READY* == port.c: sci_mpc_agent_link_up() -> port.c: sci_port_link_up() -> sci_port_general_link_up_handler() -> port_state_machine_change(, SCI_PORT_READY) -> enter port state *SCI_PORT_READY*
phy.c: enter SCI state: SCI_PHY_SUB_FINAL # Cont. from [1A] -> sci_phy_starting_final_substate_enter() -> sci_change_state(SCI_PHY_READY) -> enter SCI state: *SCI_PHY_READY* -> sci_phy_ready_state_enter() -> host.c: sci_controller_link_up() -> port_agent.link_up_handler() == port_config.c: sci_apc_agent_link_up() -> port.c: sci_port_link_up() -> sci_port_general_link_up_handler() -> port_state_machine_change(, SCI_PORT_READY) -> enter port state *SCI_PORT_READY* == port_config.c: sci_mpc_agent_link_up() -> port.c: sci_port_link_up() -> sci_port_general_link_up_handler() -> port_state_machine_change(, SCI_PORT_READY) -> enter port state *SCI_PORT_READY*
[1A] Call chains for entering SCI state: *SCI_PHY_SUB_FINAL* ------------------------------------------------------------
host.c: power_control_timeout(), atomic, timer callback (*) spin_lock_irqsave(isci_host::scic_lock, ) -> phy.c: sci_phy_consume_power_handler() -> phy.c: sci_change_state(SCI_PHY_SUB_FINAL)
host.c: sci_controller_error_handler(): atomic, irq handler (*) OR host.c: sci_controller_completion_handler(), atomic, tasklet (*) -> sci_controller_process_completions() -> sci_controller_unsolicited_frame() -> phy.c: sci_phy_frame_handler() -> sci_change_state(SCI_PHY_SUB_AWAIT_SAS_POWER) -> sci_phy_starting_await_sas_power_substate_enter() -> host.c: sci_controller_power_control_queue_insert() -> phy.c: sci_phy_consume_power_handler() -> sci_change_state(SCI_PHY_SUB_FINAL) -> sci_change_state(SCI_PHY_SUB_FINAL) -> sci_controller_event_completion() -> phy.c: sci_phy_event_handler() -> sci_phy_start_sata_link_training() -> sci_change_state(SCI_PHY_SUB_AWAIT_SATA_POWER) -> sci_phy_starting_await_sata_power_substate_enter -> host.c: sci_controller_power_control_queue_insert() -> phy.c: sci_phy_consume_power_handler() -> sci_change_state(SCI_PHY_SUB_FINAL)
[2] Call chains for entering state: *SCI_PHY_STOPPED* -----------------------------------------------------
host.c: isci_host_init() (@) spin_lock_irq(isci_host::scic_lock) -> sci_controller_initialize(), atomic (*) -> phy.c: sci_phy_initialize() -> phy.c: sci_phy_link_layer_initialization() -> phy.c: sci_change_state(SCI_PHY_STOPPED)
init.c: PCI ->remove() || PM_OPS ->suspend, process context (+) -> host.c: isci_host_deinit() -> sci_controller_stop_phys() -> phy.c: sci_phy_stop() -> sci_change_state(SCI_PHY_STOPPED)
phy.c: isci_phy_control() spin_lock_irqsave(isci_host::scic_lock, ) -> sci_phy_stop(), atomic (*) -> sci_change_state(SCI_PHY_STOPPED)
[3] Call chains for entering state: *SCI_PHY_STARTING* ------------------------------------------------------
phy.c: phy_sata_timeout(), atimer, timer callback (*) spin_lock_irqsave(isci_host::scic_lock, ) -> sci_change_state(SCI_PHY_STARTING)
host.c: phy_startup_timeout(), atomic, timer callback (*) spin_lock_irqsave(isci_host::scic_lock, ) -> sci_controller_start_next_phy() -> sci_phy_start() -> sci_change_state(SCI_PHY_STARTING)
host.c: isci_host_start() (@) spin_lock_irq(isci_host::scic_lock) -> sci_controller_start(), atomic (*) -> sci_controller_start_next_phy() -> sci_phy_start() -> sci_change_state(SCI_PHY_STARTING)
phy.c: Enter SCI state *SCI_PHY_SUB_FINAL*, atomic, check above (*) -> sci_change_state(SCI_PHY_SUB_FINAL) -> sci_phy_starting_final_substate_enter() -> sci_change_state(SCI_PHY_READY) -> Enter SCI state: *SCI_PHY_READY* -> sci_phy_ready_state_enter() -> host.c: sci_controller_link_up() -> sci_controller_start_next_phy() -> sci_phy_start() -> sci_change_state(SCI_PHY_STARTING)
phy.c: sci_phy_event_handler(), atomic, discussed earlier (*) -> sci_change_state(SCI_PHY_STARTING), 11 instances
phy.c: enter SCI state: *SCI_PHY_RESETTING*, atomic, discussed (*) -> sci_phy_resetting_state_enter() -> sci_change_state(SCI_PHY_STARTING)
As can be seen from the "(*)" markers above, almost all the call-chains are atomic. The only exception, marked with "(+)", is a PCI ->remove() and PM_OPS ->suspend() cold path. Thus, pass GFP_ATOMIC to the libsas phy event notifier.
Note, The now-replaced libsas APIs used in_interrupt() to implicitly decide which memory allocation type to use. This was only partially correct, as it fails to choose the correct GFP flags when just preemption or interrupts are disabled. Such buggy code paths are marked with "(@)" in the call chains above.
Link: https://lore.kernel.org/r/20210118100955.1761652-6-a.darwish@linutronix.de Fixes: 1c393b970e0f ("scsi: libsas: Use dynamic alloced work to avoid sas event lost") Cc: Artur Paszkiewicz artur.paszkiewicz@intel.com Reviewed-by: John Garry john.garry@huawei.com Signed-off-by: Ahmed S. Darwish a.darwish@linutronix.de Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/isci/port.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/isci/port.c b/drivers/scsi/isci/port.c index 8d93497380674..a3c58718c2600 100644 --- a/drivers/scsi/isci/port.c +++ b/drivers/scsi/isci/port.c @@ -269,8 +269,8 @@ static void isci_port_link_down(struct isci_host *isci_host, * isci_port_deformed and isci_dev_gone functions. */ sas_phy_disconnected(&isci_phy->sas_phy); - sas_notify_phy_event(&isci_phy->sas_phy, - PHYE_LOSS_OF_SIGNAL); + sas_notify_phy_event_gfp(&isci_phy->sas_phy, + PHYE_LOSS_OF_SIGNAL, GFP_ATOMIC);
dev_dbg(&isci_host->pdev->dev, "%s: isci_port = %p - Done\n", __func__, isci_port);