Re: [Question] Calling request_firmware under the spinlocks in file advansys.c

From: Hannes Reinecke
Date: Tue Sep 27 2016 - 11:16:25 EST

On 09/27/2016 01:26 PM, Vaishali Thakkar wrote:
> On Tuesday 13 September 2016 02:48 PM, Vaishali Thakkar wrote:
>> Hi,
>> In the file drivers/scsi/advansys.c we are calling function AdvISR at 2 instances
>> [in the function advansys_reset and advansys_interrupt] while holding spinlock.
>> Function AdvISR eventually calls request_firmware following this sequence of
>> routines:
>> AdvISR -> adv_async_callback -> AdvResetChipAndSB -> AdvInitAsc3550Driver ->
>> request_firmware
>> According to the definition of request_firmware it should be called from user
>> context where sleeping is allowed. And usually sleeping under the spin lock is
>> not allowed. Is it really necessary to call AdvISR under spinlocks here? Are
>> we taking care of sleeping related concern of request_firmware or am I
>> overlooking something here?
> Hi,
> Any comments on this?
AdvISR is the main interrupt handling routine, for which we definitely
will want to have interupts disabled. Plus the SCSI parallel drivers
(ab-) use the interrupt routine to do all sorts of things, and are
thereby well versed to keep interrupts disabled for an extented amount
of time.
However, we don't really have a good way of handling a request firmware
here; we probably would need to implement a workqueue to handle this
properly ...


Dr. Hannes Reinecke Teamlead Storage & Networking
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