Messages in this thread | | | Date | Mon, 18 Jan 2010 21:47:59 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: mcs7830 usb net: "scheduling while atomic" danger? |
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On Mon, 18 Jan 2010, Andreas Mohr wrote:
> 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 )
No, that's different. You are allowed to sleep with a mutex held. The thread is about spin_lock()/msleep().
spin_lock() is implicitly disabling preemption, mutex_lock() does not.
Thanks,
tglx
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