On Wed, 4 May 2011, Per Forlin wrote:
On 4 May 2011 19:34, Nicolas Pitre nicolas.pitre@linaro.org wrote:
On Wed, 4 May 2011, Per Forlin wrote:
From: Stefan Nilsson XK stefan.xk.nilsson@stericsson.com
If there is only 1 function registered it is possible to improve performance by directly calling the irq handler and avoiding the overhead of reading the CCCR registers.
Signed-off-by: Per Forlin per.forlin@linaro.org Acked-by: Ulf Hansson ulf.hansson@stericsson.com
drivers/mmc/core/sdio_irq.c | 30 ++++++++++++++++++++++++++++++ include/linux/mmc/card.h | 1 + 2 files changed, 31 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c index b300161..64c4409 100644 --- a/drivers/mmc/core/sdio_irq.c +++ b/drivers/mmc/core/sdio_irq.c @@ -32,6 +32,16 @@ static int process_sdio_pending_irqs(struct mmc_card *card) int i, ret, count; unsigned char pending;
- /*
- * Optimization, if there is only 1 function registered
- * call irq handler directly
- */
- if (card->sdio_single_irq && card->sdio_single_irq->irq_handler) {
- struct sdio_func *func = card->sdio_single_irq;
- func->irq_handler(func);
I think there is little point using a func variable here, especially since you already reference the handler pointer in the if() statement. Hence:
if (card->sdio_single_irq && card->sdio_single_irq->irq_handler) { card->sdio_single_irq->irq_handler(); return 1; }
What do you think about:
struct sdio_func *func = card->sdio_single_irq;/** Optimization, if there is only 1 function interrupt registered* call irq handler directly*/if (func) {func->irq_handler(func);return 1;}
Sure, but I'd move the assignment right before the if() in that case for clarity:
struct sdio_func *func;
/* * Optimization, if there is only 1 function interrupt registered * call irq handler directly */ func = card->sdio_single_irq; if (func) { func->irq_handler(func); return 1; } [...]
Nicolas