On Mon, May 11, 2020 at 07:03:09PM -0700, Hemant Kumar wrote: > Take write lock only to protect db_mode member of mhi channel. > This allows rest of the mhi channels to just take read lock which > fine grains the locking. It prevents channel readers to starve if > they try to enter critical section after a writer. > > Signed-off-by: Hemant Kumar <[email protected]>
Reviewed-by: Manivannan Sadhasivam <[email protected]> Thanks, Mani > --- > drivers/bus/mhi/core/pm.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c > index 345f197..de5abb2 100644 > --- a/drivers/bus/mhi/core/pm.c > +++ b/drivers/bus/mhi/core/pm.c > @@ -288,14 +288,18 @@ int mhi_pm_m0_transition(struct mhi_controller > *mhi_cntrl) > for (i = 0; i < mhi_cntrl->max_chan; i++, mhi_chan++) { > struct mhi_ring *tre_ring = &mhi_chan->tre_ring; > > - write_lock_irq(&mhi_chan->lock); > - if (mhi_chan->db_cfg.reset_req) > + if (mhi_chan->db_cfg.reset_req) { > + write_lock_irq(&mhi_chan->lock); > mhi_chan->db_cfg.db_mode = true; > + write_unlock_irq(&mhi_chan->lock); > + } > + > + read_lock_irq(&mhi_chan->lock); > > /* Only ring DB if ring is not empty */ > if (tre_ring->base && tre_ring->wp != tre_ring->rp) > mhi_ring_chan_db(mhi_cntrl, mhi_chan); > - write_unlock_irq(&mhi_chan->lock); > + read_unlock_irq(&mhi_chan->lock); > } > > mhi_cntrl->wake_put(mhi_cntrl, false); > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project
