Re: sata_mv port lockup on hotplug (kernel

From: Mark Lord
Date: Tue Apr 12 2011 - 10:56:04 EST

On 11-04-12 10:07 AM, Mark Lord wrote:
> On 11-04-12 06:30 AM, Bruce Stenning wrote:
>> I am currently inserting tracing into to try to work out what is going
>> on. From mv_write_main_irq_mask I can see that the IRQ for each port is still
>> enabled, even when ports stop responding. I see interrupts generated when I
>> hotplug or unplug disks on ports that are not locked up, but no interrupt is
>> generated at all for the ports that are locked (this is from tracing in
>> asm_do_IRQ in arch/arm/kernel/irq.c)
>> One thing I noticed was that there is no spinlock around the
>> mv_save_cached_regs/mv_edma_cfg in mv_hardreset (unlike mv_port_start and
>> mv_port_stop); why is this?
> The mv_hardreset path is run from a libata-eh thread,
> and it assumes it has exclusive access to the hardware.

Mmm.. another suspect is sata_mv's ".sff_irq_clear" function.
I don't see any locking in libata-sff.c before calling that one.

Tejun -- should libata-sff grab ap->lock before calling .sff_irq_clear,
or is that up to the LLD to do?

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