lkml.org 
[lkml]   [2020]   [May]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 13/14] bus: mhi: core: Handle write lock properly in mhi_pm_m0_transition
Date
From: Hemant Kumar <hemantk@codeaurora.org>

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 <hemantk@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
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 a5d9973059c8..e6236a3ca39d 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);
--
2.26.GIT
\
 
 \ /
  Last update: 2020-05-21 17:27    [W:0.070 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site