From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: perex@perex.cz, tiwai@suse.com
Cc: alsa-devel@alsa-project.org, Jia-Ju Bai <baijiaju1990@gmail.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/3] sound: usb: line6: Replace mdelay with msleep in line6_write_data
Date: Sun, 18 Mar 2018 22:51:59 +0800 [thread overview]
Message-ID: <1521384719-23423-1-git-send-email-baijiaju1990@gmail.com> (raw)
line6_write_data() is never called in atomic context.
The call chains ending up at line6_write_data() are:
[1] line6_write_data() <- toneport_setup() <- toneport_init()
<- line6_probe()
[2] line6_write_data() <- toneport_setup() <- toneport_reset_resume()
line6_probe() is called in toneport_probe(), pod_probe(), podhd_probe()
and variax_probe(), which are set as ".probe" in usb_driver structure.
toneport_reset_resume() is set as ".reset_resume" in usb_driver structure.
These functions are not called in atomic context.
Despite never getting called from atomic context, line6_write_data()
calls mdelay for busy wait.
That 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.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
sound/usb/line6/driver.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index 0ff5a7d..29acd86 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -426,7 +426,7 @@ int line6_write_data(struct usb_line6 *line6, unsigned address, void *data,
}
for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
- mdelay(LINE6_READ_WRITE_STATUS_DELAY);
+ msleep(LINE6_READ_WRITE_STATUS_DELAY);
ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0),
0x67,
--
1.9.1
reply other threads:[~2018-03-18 14:52 UTC|newest]
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