On Fri, Apr 17, 2020 at 03:44:28PM +0530, Manivannan Sadhasivam wrote:
> Hi Hemant,
>
> On Thu, Apr 16, 2020 at 08:37:16PM -0700, Hemant Kumar wrote:
> >
> > On 4/7/20 7:33 AM, Manivannan Sadhasivam wrote:
> > > Hi Dan,
> > >
> > > On Tue, Apr 07, 2020 at 04:55:59PM +0300, Dan Carpenter wrote:
> > > > Hello Manivannan Sadhasivam,
> > > >
> > > > The patch 189ff97cca53: "bus: mhi: core: Add support for data
> > > > transfer" from Feb 20, 2020, leads to the following static checker
> > > > warning:
> > > >
> > > > drivers/bus/mhi/core/main.c:1153 mhi_queue_buf()
> > > > error: double locked 'mhi_chan->lock' (orig line 1110)
> > > >
> > > > drivers/bus/mhi/core/main.c
> > > > 1142 }
> > > > 1143
> > > > 1144 /* Toggle wake to exit out of M2 */
> > > > 1145 mhi_cntrl->wake_toggle(mhi_cntrl);
> > > > 1146
> > > > 1147 if (mhi_chan->dir == DMA_TO_DEVICE)
> > > > 1148 atomic_inc(&mhi_cntrl->pending_pkts);
> > > > 1149
> > > > 1150 if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl))) {
> > > > 1151 unsigned long flags;
> > > > 1152
> > > > 1153 read_lock_irqsave(&mhi_chan->lock, flags);
> >
> > parse_xfer_event is taking read lock : read_lock_bh(&mhi_chan->lock); first
> > and later
> >
> > mhi_queue_buf takes read lock: read_lock_irqsave(&mhi_chan->lock, flags);
> >
> > Both are read locks which are recursive, is this problematic ?
> >
>
> read_locks are recursive but I wanted to make the static checker happy.
Don't do things just to make the static checker happy.
regards,
dan carpenter
