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

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

[Vaishali Thakkar]

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?

Thank you.

-- 
Vaishali

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

[Vaishali Thakkar]

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?

Thanks

> Thank you.
> 

-- 
Vaishali

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

[Hannes Reinecke]

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 ...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare@suse.de			               +49 911 74053 688
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