Re: [PATCH 08/14] scsi: qla4xxx: qla4_82xx_rom_lock(): Remove in_interrupt().

Daniel Wagner
2020-11-30T14:34:17Z

On Thu, Nov 26, 2020 at 02:29:46PM +0100, Sebastian Andrzej Siewior wrote:
> From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
>
> 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().
>
> Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
> Signed-off-by: Sebastian Andrzej Siewior <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>