5ce7902902
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_link_up(). Below
is the context analysis for all of its call chains:
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()
-> sci_port_activate_phy()
-> isci_port_link_up()
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()
-> sci_port_activate_phy()
-> isci_port_link_up()
phy.c: enter SCI state: *SCI_PHY_SUB_FINAL* # Cont. from [1]
-> phy.c: sci_phy_starting_final_substate_enter()
-> phy.c: sci_change_state(SCI_PHY_READY)
-> enter SCI state: *SCI_PHY_READY*
-> phy.c: sci_phy_ready_state_enter()
-> host.c: sci_controller_link_up()
-> .link_up_handler()
== port_config.c: sci_apc_agent_link_up()
-> port.c: sci_port_link_up()
-> (continue at [A])
== port_config.c: sci_mpc_agent_link_up()
-> port.c: sci_port_link_up()
-> (continue at [A])
port_config.c: mpc_agent_timeout(), atomic, timer callback (*)
spin_lock_irqsave(isci_host::scic_lock, )
-> ->link_up_handler()
== port_config.c: sci_apc_agent_link_up()
-> port.c: sci_port_link_up()
-> (continue at [A])
== port_config.c: sci_mpc_agent_link_up()
-> port.c: sci_port_link_up()
-> (continue at [A])
[A] port.c: sci_port_link_up()
-> sci_port_activate_phy()
-> isci_port_link_up()
-> sci_port_general_link_up_handler()
-> sci_port_activate_phy()
-> isci_port_link_up()
[1] 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, all the call-chains are
atomic. Pass GFP_ATOMIC to 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/20210118100955.1761652-7-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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.