[bug report] bus: mhi: ep: Add support for suspending and resuming channels

[Dan Carpenter <error27@gmail.com>]

Hello Manivannan Sadhasivam,

The patch e4b7b5f0f30a: "bus: mhi: ep: Add support for suspending and
resuming channels" from Apr 5, 2022, leads to the following Smatch
static checker warning:

	drivers/bus/mhi/ep/main.c:1141 mhi_ep_resume_channels()
	warn: sleeping in atomic context

drivers/bus/mhi/ep/main.c
    1129 void mhi_ep_resume_channels(struct mhi_ep_cntrl *mhi_cntrl)
    1130 {
    1131         struct mhi_ep_chan *mhi_chan;
    1132         u32 tmp;
    1133         int i;
    1134 
    1135         for (i = 0; i < mhi_cntrl->max_chan; i++) {
    1136                 mhi_chan = &mhi_cntrl->mhi_chan[i];
    1137 
    1138                 if (!mhi_chan->mhi_dev)
    1139                         continue;
    1140 
--> 1141                 mutex_lock(&mhi_chan->lock);
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This is called from mhi_ep_set_m0_state().  The mhi_ep_set_m0_state()
function takes a spinlock so we can't take a mutex if we're holding a
spinlock.

Enable CONFIG_DEBUG_ATOMIC_SLEEP for more information.

regards,
dan carpenter