[PATCH] arm: Improve MMC performance on Versatile Express

[Russell King - ARM Linux]

On Fri, Jan 21, 2011 at 05:20:57PM -0500, Nicolas Pitre wrote:
> The only solution in that case is to give top priority to the FIFO IRQ 
> and never disable IRQs when in interrupt context, except for that FIFO 
> servicing handler which should keep IRQs masked out throughout.  In any 
> case this would certainly be only a hack for badly misdesigned hardware.

Not possible anymore.  The kernel's IRQ handling has changed such that
generic code now ensures that IRQs are disabled irrespective of the
IRQF_DISABLED flag.  All IRQ handlers are called with IRQs disabled,
and they remain that way until they call local_irq_enable().