mcs7830 usb net: "scheduling while atomic" danger?

From: Andreas Mohr
Date: Mon Jan 18 2010 - 13:49:49 EST


Hi,

drivers/net/usb/mcs7830.c does several:

mutex_lock(&dev->phy_mutex);
/* write the MII command */
ret = mcs7830_set_reg(dev, HIF_REG_PHY_CMD1, 2, cmd);
if (ret < 0)
goto out;

/* wait for the data to become valid, should be within < 1ms */
for (i = 0; i < 10; i++) {
ret = mcs7830_get_reg(dev, HIF_REG_PHY_CMD1, 2, cmd);
if ((ret < 0) || (cmd[1] &
HIF_REG_PHY_CMD2_READY_FLAG_BIT))
break;
ret = -EIO;
msleep(1);
}


Forgive me, but doesn't that mutex_lock()/msleep() (ab)use mean
risking a "scheduling while atomic"?
(such as discussed in e.g.
http://search.luky.org/linux-kernel.2004/msg92817.html )


And, if that is the case, shouldn't all such cases simply be killed for
good via a capable semantic patch?

Thanks,

Andreas Mohr
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