Re: [PATCH 4/4] Btrfs: add basic DIO read/write support V3

From: Josef Bacik
Date: Thu May 13 2010 - 11:23:20 EST


On Thu, May 13, 2010 at 11:14:30AM -0400, Christoph Hellwig wrote:
> On Wed, May 12, 2010 at 04:40:53PM -0400, Josef Bacik wrote:
> > V1->V2
> > -Use __blockdev_direct_IO instead of helper
> > -Use KM_IRQ0 for kmap instead of KM_USER0
>
> I still don't think this is correct. The completion can come from
> softirq and hardirq context, and possibly even normal process context.
> You either need to check for all these, or you need to use the generic
> complete in user context helper btrfs has available for other types
> of I/O.
>

AIO's aio_complete does kmap with KM_IRQ0/1 and it gets called in the same
context as the btrfs completion handler, so if it's ok for aio_complete it
should be ok for btrfs right? Thanks,

Josef
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