linux-kernel - [PATCH] sound: usb: quirks: Replace mdelay() with msleep() and usleep

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Message-Id: <20180727085528.5802-1-baijiaju1990@gmail.com>
Date:   Fri, 27 Jul 2018 16:55:28 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     perex@...ex.cz, tiwai@...e.com, jussi@...arnerd.net,
        nob77413@...il.com, kai.heng.feng@...onical.com,
        elfring@...rs.sourceforge.net, daniel@...que.org,
        ruslan.bilovol@...il.com
Cc:     alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] sound: usb: quirks: Replace mdelay() with msleep() and usleep_range()

snd_usb_select_mode_quirk(), snd_usb_set_interface_quirk() and 
snd_usb_ctl_msg_quirk() are never called in atomic context.
They call mdelay() to busily wait, which is not necessary.
mdelay() can be replaced with msleep() and usleep_range().

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 sound/usb/quirks.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index acbeb52f6fd6..9eed650c54d4 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1181,7 +1181,7 @@ int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
 		if (err < 0)
 			return err;
 
-		mdelay(20); /* Delay needed after setting the interface */
+		msleep(20); /* Delay needed after setting the interface */
 
 		/* Vendor mode switch cmd is required. */
 		if (fmt->formats & SNDRV_PCM_FMTBIT_DSD_U32_BE) {
@@ -1202,7 +1202,7 @@ int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
 				return err;
 
 		}
-		mdelay(20);
+		msleep(20);
 	}
 	return 0;
 }
@@ -1249,7 +1249,7 @@ void snd_usb_set_interface_quirk(struct usb_device *dev)
 	switch (USB_ID_VENDOR(chip->usb_id)) {
 	case 0x23ba: /* Playback Design */
 	case 0x0644: /* TEAC Corp. */
-		mdelay(50);
+		msleep(50);
 		break;
 	}
 }
@@ -1269,7 +1269,7 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
 	 */
 	if (USB_ID_VENDOR(chip->usb_id) == 0x23ba &&
 	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
-		mdelay(20);
+		msleep(20);
 
 	/*
 	 * "TEAC Corp." products need a 20ms delay after each
@@ -1277,14 +1277,14 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
 	 */
 	if (USB_ID_VENDOR(chip->usb_id) == 0x0644 &&
 	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
-		mdelay(20);
+		msleep(20);
 
 	/* ITF-USB DSD based DACs functionality need a delay
 	 * after each class compliant request
 	 */
 	if (is_itf_usb_dsd_dac(chip->usb_id)
 	    && (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
-		mdelay(20);
+		msleep(20);
 
 	/* Zoom R16/24, Logitech H650e, Jabra 550a needs a tiny delay here,
 	 * otherwise requests like get/set frequency return as failed despite
@@ -1294,7 +1294,7 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
 	     chip->usb_id == USB_ID(0x046d, 0x0a46) ||
 	     chip->usb_id == USB_ID(0x0b0e, 0x0349)) &&
 	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
-		mdelay(1);
+		usleep_range(1000, 2000);
 }
 
 /*
-- 
2.17.0