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Ahmed S. Darwish
014aced18a
qla4_82xx_rom_lock() spins on a certain hardware state until it is
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: qla4_82xx_rom_lock() is always called
from process context. Below is an analysis of its callers:
- ql4_nx.c: qla4_82xx_rom_fast_read(), all process context callers:
=> ql4_nx.c: qla4_82xx_pinit_from_rom(), GFP_KERNEL allocation
=> ql4_nx.c: qla4_82xx_load_from_flash(), msleep() in a loop
- ql4_nx.c: qla4_82xx_pinit_from_rom(), earlier discussed
- ql4_nx.c: qla4_82xx_rom_lock_recovery(), bound to "isp_operations"
->rom_lock_recovery() hook, which has one process context caller,
qla4_8xxx_device_bootstrap(), with callers:
=> ql4_83xx.c: qla4_83xx_need_reset_handler(), process, msleep()
=> ql4_nx.c: qla4_8xxx_device_state_handler(), multiple msleep()s
- ql4_nx.c: qla4_82xx_read_flash_data(), has cond_resched()
Remove the in_interrupt() check. Mark, qla4_82xx_rom_lock(), and the
->rom_lock_recovery() hook, with "Context: task, can sleep".
Change qla4_82xx_rom_lock() implementation to sleep 20ms, instead of a
schedule(), for each spin. This is more deterministic, and it matches
the other implementations bound to ->rom_lock_recovery().
Link: https://lore.kernel.org/r/20201126132952.2287996-9-bigeasy@linutronix.de
Cc: Nilesh Javali <njavali@marvell.com>
Cc: Manish Rangankar <mrangankar@marvell.com>
Cc: <GR-QLogic-Storage-Upstream@marvell.com>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@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.