I don't know if there are less efficient ways to code that. Get rid of the loop mess and use efficient code. Signed-off-by: Thomas Gleixner --- drivers/irqchip/spear-shirq.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) Index: linux/drivers/irqchip/spear-shirq.c =================================================================== --- linux.orig/drivers/irqchip/spear-shirq.c +++ linux/drivers/irqchip/spear-shirq.c @@ -224,23 +224,20 @@ static void shirq_handler(unsigned irq, struct spear_shirq *shirq = irq_get_handler_data(irq); struct irq_data *idata = irq_desc_get_irq_data(desc); struct irq_chip *chip = irq_data_get_irq_chip(idata); - u32 i, j, val, mask; + u32 pend; chip->irq_ack(idata); - mask = shirq->mask; - while ((val = readl(shirq->base + shirq->regs.status_reg) & - mask)) { + pend = readl(shirq->base + shirq->regs.status_reg) & shirq->mask; + pend >>= shirq->offset; - val >>= shirq->offset; - for (i = 0, j = 1; i < shirq->nr_irqs; i++, j <<= 1) { + while (pend) { + int irq = __ffs(pend); - if (!(j & val)) - continue; - - generic_handle_irq(shirq->virq_base + i); - } + pend &= ~(0x1 << irq); + generic_handle_irq(shirq->virq_base + irq); } + chip->irq_unmask(idata); }