On Mon, Nov 27, 2023 at 03:19:49PM +0800, Qiang Yu wrote:
>
> On 11/24/2023 6:09 PM, Manivannan Sadhasivam wrote:
> > On Tue, Nov 14, 2023 at 01:27:41PM +0800, Qiang Yu wrote:
> > > From: Hemant Kumar <quic_hemantk@xxxxxxxxxxx>
> > >
> > > If CONFIG_TRACE_IRQFLAGS is enabled, irq will be enabled once __local_bh_
> > > enable_ip is called as part of write_unlock_bh. Hence, let's take irqsave
> > "__local_bh_enable_ip" is a function name, so you should not break it.
> Thanks for let me know, will note this in following patch.
> >
> > > lock after TRE is generated to avoid running write_unlock_bh when irqsave
> > > lock is held.
> > >
> > I still don't understand this commit message. Where is the write_unlock_bh()
> > being called?
> >
> > - Mani
> Write_unlock_bh() is invoked in mhi_gen_te()
> The calling flow is like
> mhi_queue
> read_lock_irqsave(&mhi_cntrl->pm_lock, flags)
> mhi_gen_tre
> write_lock_bh(&mhi_chan->lock)
> write_unlock_bh(&mhi_chan->lock) // Will enable irq if
> CONFIG_TRACE_IRQFLAGS is enabled
> read_lock_irqsave(&mhi_cntrl->pm_lock, flags)
>
> after adding this patch, the calling flow becomes
>
> mhi_queue
> mhi_gen_tre
> write_lock_bh(&mhi_chan->lock)
> write_unlock_bh(&mhi_chan->lock)
> read_lock_irqsave(&mhi_cntrl->pm_lock, flags)
> read_lock_irqsave(&mhi_cntrl->pm_lock, flags)
So this patch essentially fixes the issue caused by patch 1? If so, this should
be squashed into patch 1.
- Mani
> >
> > > Signed-off-by: Hemant Kumar <quic_hemantk@xxxxxxxxxxx>
> > > Signed-off-by: Lazarus Motha <quic_lmotha@xxxxxxxxxxx>
> > > Signed-off-by: Qiang Yu <quic_qianyu@xxxxxxxxxxx>
> > > ---
> > > drivers/bus/mhi/host/main.c | 13 +++++--------
> > > 1 file changed, 5 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
> > > index 33f27e2..d7abd0b 100644
> > > --- a/drivers/bus/mhi/host/main.c
> > > +++ b/drivers/bus/mhi/host/main.c
> > > @@ -1128,17 +1128,15 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info,
> > > if (unlikely(MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)))
> > > return -EIO;
> > > - read_lock_irqsave(&mhi_cntrl->pm_lock, flags);
> > > -
> > > ret = mhi_is_ring_full(mhi_cntrl, tre_ring);
> > > - if (unlikely(ret)) {
> > > - ret = -EAGAIN;
> > > - goto exit_unlock;
> > > - }
> > > + if (unlikely(ret))
> > > + return -EAGAIN;
> > > ret = mhi_gen_tre(mhi_cntrl, mhi_chan, buf_info, mflags);
> > > if (unlikely(ret))
> > > - goto exit_unlock;
> > > + return ret;
> > > +
> > > + read_lock_irqsave(&mhi_cntrl->pm_lock, flags);
> > > /* Packet is queued, take a usage ref to exit M3 if necessary
> > > * for host->device buffer, balanced put is done on buffer completion
> > > @@ -1158,7 +1156,6 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info,
> > > if (dir == DMA_FROM_DEVICE)
> > > mhi_cntrl->runtime_put(mhi_cntrl);
> > > -exit_unlock:
> > > read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags);
> > > return ret;
> > > --
> > > 2.7.4
> > >
> > >
>
--
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