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Message-Id: <1523323748-28361-1-git-send-email-baijiaju1990@gmail.com> Date: Tue, 10 Apr 2018 09:29:08 +0800 From: Jia-Ju Bai <baijiaju1990@...il.com> To: stern@...land.harvard.edu, gregkh@...uxfoundation.org Cc: linux-usb@...r.kernel.org, usb-storage@...ts.one-eyed-alien.net, linux-kernel@...r.kernel.org, Jia-Ju Bai <baijiaju1990@...il.com> Subject: [PATCH] usb: storage: Replace mdelay with msleep in init_freecom init_freecom() is never called in atomic context. init_freecom() is set as ".initFunction" through UNUSUAL_DEV(). And ->initFunction() is only called by usb_stor_acquire_resources(), which is only called by usb_stor_probe2(). usb_stor_probe2() is called by *_probe() functions (like alauda_probe()) for each USB driver. *_probe() functions are set ".probe" in struct usb_driver. These functions are not called in atomic context. Despite never getting called from atomic context, init_freecom() calls mdelay() to busily wait. This is not necessary and can be replaced with msleep() to avoid busy waiting. This is found by a static analysis tool named DCNS written by myself. And I also manually check it. Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com> --- drivers/usb/storage/freecom.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/storage/freecom.c b/drivers/usb/storage/freecom.c index c0a5d95..c7f886d 100644 --- a/drivers/usb/storage/freecom.c +++ b/drivers/usb/storage/freecom.c @@ -477,7 +477,7 @@ static int init_freecom(struct us_data *us) usb_stor_dbg(us, "result from activate reset is %d\n", result); /* wait 250ms */ - mdelay(250); + msleep(250); /* clear reset */ result = usb_stor_control_msg(us, us->send_ctrl_pipe, @@ -485,7 +485,7 @@ static int init_freecom(struct us_data *us) usb_stor_dbg(us, "result from clear reset is %d\n", result); /* wait 3 seconds */ - mdelay(3 * 1000); + msleep(3 * 1000); return USB_STOR_TRANSPORT_GOOD; } -- 1.9.1
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