lkml.org 
[lkml]   [2021]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.11 372/775] scsi: isci: Pass gfp_t flags in isci_port_bc_change_received()
    Date
    From: Ahmed S. Darwish <a.darwish@linutronix.de>

    [ Upstream commit 71dca5539fcf977aead0c9ea1962e70e78484b8e ]

    Use the new libsas event notifiers API, which requires callers to
    explicitly pass the gfp_t memory allocation flags.

    libsas sas_notify_port_event() is called from
    isci_port_bc_change_received(). Below is the context analysis for all of
    its call chains:

    host.c: sci_controller_error_handler(): atomic, irq handler (*)
    OR host.c: sci_controller_completion_handler(), atomic, tasklet (*)
    -> sci_controller_process_completions()
    -> sci_controller_event_completion()
    -> phy.c: sci_phy_event_handler()
    -> port.c: sci_port_broadcast_change_received()
    -> isci_port_bc_change_received()

    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_set_phy()
    -> phy.c: sci_phy_set_port()
    -> port.c: sci_port_broadcast_change_received()
    -> isci_port_bc_change_received()

    port_config.c: apc_agent_timeout(), atomic, timer callback (*)
    -> sci_apc_agent_configure_ports()
    -> port.c: sci_port_add_phy()
    -> sci_port_set_phy()
    -> phy.c: sci_phy_set_port()
    -> port.c: sci_port_broadcast_change_received()
    -> isci_port_bc_change_received()

    phy.c: enter SCI state: *SCI_PHY_STOPPED* # Cont. from [1]
    -> 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_clear_phy()
    -> phy.c: sci_phy_set_port()
    -> port.c: sci_port_broadcast_change_received()
    -> isci_port_bc_change_received()

    phy.c: enter SCI state: *SCI_PHY_STARTING* # Cont. from [2]
    -> 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()
    -> sci_port_clear_phy()
    -> phy.c: sci_phy_set_port()
    -> port.c: sci_port_broadcast_change_received()
    -> isci_port_bc_change_received()

    [1] 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)

    [2] 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* # Cont. from [2A]
    -> 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

    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()
    -> sci_change_state(SCI_PHY_STARTING)

    [2A] 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)

    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 port
    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/20210118100955.1761652-8-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 | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    diff --git a/drivers/scsi/isci/port.c b/drivers/scsi/isci/port.c
    index 10136ae466e20..e50c3b0deeb30 100644
    --- a/drivers/scsi/isci/port.c
    +++ b/drivers/scsi/isci/port.c
    @@ -164,7 +164,8 @@ static void isci_port_bc_change_received(struct isci_host *ihost,
    "%s: isci_phy = %p, sas_phy = %p\n",
    __func__, iphy, &iphy->sas_phy);

    - sas_notify_port_event(&iphy->sas_phy, PORTE_BROADCAST_RCVD);
    + sas_notify_port_event_gfp(&iphy->sas_phy,
    + PORTE_BROADCAST_RCVD, GFP_ATOMIC);
    sci_port_bcn_enable(iport);
    }

    --
    2.27.0


    \
     
     \ /
      Last update: 2021-03-02 05:10    [W:2.392 / U:0.400 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site