On Thu, 13 May 2010 11:31:45 -0400 Josef Bacik <josef@xxxxxxxxxx> wrote: > 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, > Using KM_USERx from irq context is a horrid, horrid bug. Using KM_IRQx with local interrupts enabled is a ditto. It's OK to use KM_IRQx from process context as long as local interrupts are disabled. kmap slots are just per-cpu variables. Each one has a particular usage convention: process-context-only, must-be-irq-safe, etc. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
