Re: [PATCH] scsi_lib: increase {host|target|device}_busy count after dispatch cmd

[Ganesh Mahendran]

Hi, Bart:

2018-03-02 7:11 GMT+08:00 Bart Van Assche <Bart.VanAssche@xxxxxxx>:
> On Mon, 2017-06-05 at 17:37 +0800, Ganesh Mahendran wrote:
>> In android system, when there are lots of threads running. Thread A
>> holding *host_busy* count is easily to be preempted, and if at the
>> same time, thread B set *host_blocked*, then all other threads will
>> be io blocked.
>
> Hello Ganesh,
>
> Have you considered to insert preempt_disable() and preempt_enable() calls
> where necessary to achieve the same effect? I think that would result in a
> much less intrusive patch.

Yes, preempt_disable()preempt_enable will also achieve the same effect.
But I just think preempt_disable()preempt_enable may be a little heavy for
this problem which can be fixed by increaseing {host|target|device}_busy count
after dispatch cmd.

Thanks.

>
> Thanks,
>
> Bart.
>
>