Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Kumar Gala <galak@kernel.crashing.org>]

On Feb 21, 2007, at 3:31 PM, Andrew Morton wrote:

> On Wed, 21 Feb 2007 16:22:17 -0500 (EST)
> Alan Stern <stern@rowland.harvard.edu> wrote:
>
>> On Wed, 21 Feb 2007, Andrew Morton wrote:
>>
>>>>> It seems like usb-storage and aio are completely off in the weeds.
>>>>> Ideas?
>>>>
>>>> It seems usb-storage should remove some kmalloc and use mempool 
>>>> () for
>>>> urb...  Is someone working on this? And idea?
>>>
>>> I think Pete said that we're supposed to be using GFP_NOIO in there.
>>
>> We _are_ using it.
>
> How admirably prompt.
>
>>> Not that it'll help much: the VM calls throttle_vm_writeout() for  
>>> GFP_NOIO
>>> and GFP_NOFS allocations, which is a bug.  Because if the caller  
>>> holds
>>> locks which prevent filesystem or IO progress, we deadlock.
>>>
>>> I'll fix the VM if someone else fixes USB ;)
>>
>> What else needs to be fixed?
>
> Would be nice if someone can confirm that this fixes it:

Doesn't seem to help my problem in a quick test, will get more data  
in the morning.

- k