All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: gregkh@linuxfoundation.org
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH 2/2] usb: isp1760: Replace mdelay with msleep in isp1760_stop
Date: Tue, 10 Apr 2018 15:37:06 +0800	[thread overview]
Message-ID: <1523345826-29223-1-git-send-email-baijiaju1990@gmail.com> (raw)

isp1760_stop() is never called in atomic context.

The call chain ending up at isp1760_stop() is:
[1] isp1760_stop() <- isp1760_shutdown()

isp1760_shutdown() is set as ".shutdown" in struct hc_driver.
isp1760_stop() is also set as ".stop" in hc_driver.
These functions are not called in atomic context.

Despite never getting called from atomic context, isp1760_stop()
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@gmail.com>
---
 drivers/usb/isp1760/isp1760-hcd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/isp1760/isp1760-hcd.c b/drivers/usb/isp1760/isp1760-hcd.c
index 8e59e0c..5599310 100644
--- a/drivers/usb/isp1760/isp1760-hcd.c
+++ b/drivers/usb/isp1760/isp1760-hcd.c
@@ -2090,7 +2090,7 @@ static void isp1760_stop(struct usb_hcd *hcd)
 
 	isp1760_hub_control(hcd, ClearPortFeature, USB_PORT_FEAT_POWER,	1,
 			NULL, 0);
-	mdelay(20);
+	msleep(20);
 
 	spin_lock_irq(&priv->lock);
 	ehci_reset(hcd);
-- 
1.9.1


WARNING: multiple messages have this Message-ID (diff)
From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: gregkh@linuxfoundation.org
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [2/2] usb: isp1760: Replace mdelay with msleep in isp1760_stop
Date: Tue, 10 Apr 2018 15:37:06 +0800	[thread overview]
Message-ID: <1523345826-29223-1-git-send-email-baijiaju1990@gmail.com> (raw)

isp1760_stop() is never called in atomic context.

The call chain ending up at isp1760_stop() is:
[1] isp1760_stop() <- isp1760_shutdown()

isp1760_shutdown() is set as ".shutdown" in struct hc_driver.
isp1760_stop() is also set as ".stop" in hc_driver.
These functions are not called in atomic context.

Despite never getting called from atomic context, isp1760_stop()
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@gmail.com>
---
 drivers/usb/isp1760/isp1760-hcd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/isp1760/isp1760-hcd.c b/drivers/usb/isp1760/isp1760-hcd.c
index 8e59e0c..5599310 100644
--- a/drivers/usb/isp1760/isp1760-hcd.c
+++ b/drivers/usb/isp1760/isp1760-hcd.c
@@ -2090,7 +2090,7 @@ static void isp1760_stop(struct usb_hcd *hcd)
 
 	isp1760_hub_control(hcd, ClearPortFeature, USB_PORT_FEAT_POWER,	1,
 			NULL, 0);
-	mdelay(20);
+	msleep(20);
 
 	spin_lock_irq(&priv->lock);
 	ehci_reset(hcd);

             reply	other threads:[~2018-04-10  7:37 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-10  7:37 Jia-Ju Bai [this message]
2018-04-10  7:37 ` [2/2] usb: isp1760: Replace mdelay with msleep in isp1760_stop Jia-Ju Bai

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1523345826-29223-1-git-send-email-baijiaju1990@gmail.com \
    --to=baijiaju1990@gmail.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.