From: va.storage2010@gmail.com (va stg2010)
To: kernelnewbies@lists.kernelnewbies.org
Subject: On sg_miter_next sg_miter_stop
Date: Wed, 16 Mar 2011 11:48:36 -0700 [thread overview]
Message-ID: <AANLkTiku1okkPiGFHERH7v5=0ZZPbww-QAfoAjNT1iwB@mail.gmail.com> (raw)
In-Reply-To: <AANLkTikvQVzcEA_b8dkV5=k65oJ1PTVaxpzPxVGm8goa@mail.gmail.com>
On Wed, Mar 16, 2011 at 10:49 AM, Mulyadi Santosa
<mulyadi.santosa@gmail.com> wrote:
> Hi...
>
> On Thu, Mar 17, 2011 at 00:26, va stg2010 <va.storage2010@gmail.com> wrote:
>> I also looked into sg_miter_next() ? and sg_miter_stop()
>> implementations. ?They ?are calling ?kmap_atomic() ? and
>> kunmap_atomic() respectively. ? ?Based on comment -- ?Is following an
>> illegal operation? and why?
>> 1) ?IRQ disabled
>> 2) sg_miter_next , meaning kmap_atomic
>> 3) IRQ enabled
>> 4) ?IRQ ?disabled again little later
>> 5) sg_miter_stop, meaning kunmap_atomic()
>>
>> The above sequence caused following scheduler messages (if
>> sg_miter_stop() ?is moved between step1 & step3 then following error
>> messages disappeared) :--------
>> BUG: scheduling while atomic: swapper/0/0xffffffff
>> Modules linked in: my_scsi_lld
>
> quite likely the error was triggered not due to kmap_atomic() and
> kunmap_atomic(), but due to something that you do toward the page
> allocated via kmap_atomic() itself.
The page is given to my scsi mid layer LLDD by linux-scsi layer for
SCSI read request. When sg_miter_stop() happens the page will have
READ data available and I call scsi_done().
prev parent reply other threads:[~2011-03-16 18:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-16 1:40 On sg_miter_next sg_miter_stop va stg2010
2011-03-16 4:50 ` Mulyadi Santosa
2011-03-16 17:26 ` va stg2010
2011-03-16 17:49 ` Mulyadi Santosa
2011-03-16 18:48 ` va stg2010 [this message]
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