On Thu, Nov 26, 2020 at 02:29:41PM +0100, Sebastian Andrzej Siewior wrote:
From: "Ahmed S. Darwish" <a.darwish@xxxxxxxxxxxxx>
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().
Fixes: f4f5df23bf72 ("[SCSI] qla4xxx: Added support for ISP82XX")
Signed-off-by: Ahmed S. Darwish <a.darwish@xxxxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Nilesh Javali <njavali@xxxxxxxxxxx>
Cc: Manish Rangankar <mrangankar@xxxxxxxxxxx>
Cc: <GR-QLogic-Storage-Upstream@xxxxxxxxxxx>
Reviewed-by: Daniel Wagner <dwagner@xxxxxxx>
