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a93c383531
qla4_82xx_crb_win_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.
The in_interrupt() macro is ill-defined as it does not provide what the
name suggests, and it does not catch the intended use-case here.
qla4_82xx_crb_win_lock() is always invoked with scsi_qla_host::hw_lock
acquired, with disabled interrupts. If the caller is in process context, as
in qla4_82xx_need_reset_handler(), then in_interrupt() will return false
even though it is not allowed to call schedule().
Remove the in_interrupt() check.
Change qla4_82xx_crb_win_lock() specification to a purely atomic
function. Mark it as static, remove its forward declaration, and move it
above its callers. To avoid hammering the PCI bus while spinning, use a 10
micro-second delay instead of cpu_relax().
Link: https://lore.kernel.org/r/20201126132952.2287996-4-bigeasy@linutronix.de
Fixes: f4f5df23bf ("[SCSI] qla4xxx: Added support for ISP82XX")
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.