Messages in this thread | | | Date | Thu, 13 May 2010 11:43:36 -0400 | From | Josef Bacik <> | Subject | Re: [PATCH 4/4] Btrfs: add basic DIO read/write support V3 |
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On Thu, May 13, 2010 at 11:26:39AM -0400, Christoph Hellwig wrote: > On Thu, May 13, 2010 at 11:31:45AM -0400, Josef Bacik wrote: > > 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, > > aio_complete does a spin_lock_irqsave before that, which disables > interrupts on the local CPU. >
Ok so looking at debug_kmap_atomic it seems that KM_IRQ0 is ok to use in all cases, in_irq(), !irqs_disabled() and !in_interrupt(), so I should be safe. If you still don't like it, would something like this be acceptable?
if (in_interrupt() || irqs_disabled()) { if (in_irq()) type = KM_IRQ0; else if (!irqs_disabled()) type = KM_SOFTIRQ0; else type = KM_IRQ0; } else { type = KM_USER0; }
Hrm, you'd think somebody would have had this problem before and already come up with a nice helper, oh well. Thanks,
Josef
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