Re: [PATCH] libata: ignore EH scheduling during initialization

[Jeff Garzik <jeff@garzik.org>]

Tejun Heo wrote:
> libata enables SCSI host during ATA host activation which happens
> after IRQ handler is registered and IRQ is enabled.  All ATA ports are
> in frozen state when IRQ is enabled but frozen ports may raise limited
> number of IRQs after being frozen - IOW, ->freeze() is not responsible
> for clearing pending IRQs.  During normal operation, the IRQ handler
> is responsible for clearing spurious IRQs on frozen ports and it
> usually doesn't require any extra code.
> 
> Unfortunately, during host initialization, the IRQ handler can end up
> scheduling EH for a port whose SCSI host isn't initialized yet.  This
> results in OOPS in the SCSI midlayer.  This is relatively short window
> and scheduling EH for probing is the first thing libata does after
> initialization, so ignoring EH scheduling until initialization is
> complete solves the problem nicely.
> 
> This problem was spotted by Berck E. Nash in the following thread.
> 
>   http://thread.gmane.org/gmane.linux.kernel/519412
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>
> Cc: Berck E. Nash <flyboy@gmail.com>

applied