From f933d160b1e71dd8ab3d4e2586b9ff0f584d985c Mon Sep 17 00:00:00 2001 From: Jia-Ju Bai Date: Thu, 7 May 2020 12:25:21 +0200 Subject: [PATCH] media: usb: ttusb-dec: reduce the number of memory reads in ttusb_dec_handle_irq() In ttusb_dec_handle_irq(), buffer[4] is continuously read from memory three times, without being modified. To reduce the number of memory reads, buffer[4] is first assigned to a local variable index, and then index is used to replace buffer[4]. Signed-off-by: Jia-Ju Bai Reviewed-by: Greg Kroah-Hartman Signed-off-by: Sean Young Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/ttusb-dec/ttusb_dec.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/media/usb/ttusb-dec/ttusb_dec.c b/drivers/media/usb/ttusb-dec/ttusb_dec.c index 3198f96..b8d39b2 100644 --- a/drivers/media/usb/ttusb-dec/ttusb_dec.c +++ b/drivers/media/usb/ttusb-dec/ttusb_dec.c @@ -250,6 +250,7 @@ static void ttusb_dec_handle_irq( struct urb *urb) struct ttusb_dec *dec = urb->context; char *buffer = dec->irq_buffer; int retval; + int index = buffer[4]; switch(urb->status) { case 0: /*success*/ @@ -281,11 +282,11 @@ static void ttusb_dec_handle_irq( struct urb *urb) * this should/could be added later ... * for now lets report each signal as a key down and up */ - if (buffer[4] - 1 < ARRAY_SIZE(rc_keys)) { - dprintk("%s:rc signal:%d\n", __func__, buffer[4]); - input_report_key(dec->rc_input_dev, rc_keys[buffer[4] - 1], 1); + if (index - 1 < ARRAY_SIZE(rc_keys)) { + dprintk("%s:rc signal:%d\n", __func__, index); + input_report_key(dec->rc_input_dev, rc_keys[index - 1], 1); input_sync(dec->rc_input_dev); - input_report_key(dec->rc_input_dev, rc_keys[buffer[4] - 1], 0); + input_report_key(dec->rc_input_dev, rc_keys[index - 1], 0); input_sync(dec->rc_input_dev); } } -- 2.7.4