On 2/24/2021 2:55 AM, Manivannan Sadhasivam wrote:
On Wed, Feb 17, 2021 at 09:43:31AM -0700, Jeffrey Hugo wrote:
We cannot process a power_down if the power state is DISABLED. There is
no valid mhi_ctxt in that case, so attepting to process the power_down
will likely result in a null pointer dereference. If the power state is
DISABLED, there is nothing to do anyways, so just bail early.
Signed-off-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
---
v2: Fix subject and tweak the locking to avoid needless lock/unlock/relock
drivers/bus/mhi/core/pm.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 56ba3ab..47f6621 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -1144,6 +1144,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
mhi_deinit_dev_ctxt(mhi_cntrl);
error_dev_ctxt:
+ mhi_cntrl->pm_state = MHI_PM_DISABLE;
mutex_unlock(&mhi_cntrl->pm_mutex);
return ret;
@@ -1155,11 +1156,17 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
enum mhi_pm_state cur_state, transition_state;
struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ mutex_lock(&mhi_cntrl->pm_mutex);
+ cur_state = mhi_cntrl->pm_state;
As I said in my previous review, you should use pm_lock for reading the
pm_state.
You also said on IRC that is a refactor of the entire driver, and not a
blocker for this fix. Based on that, I intrepreted your comments as
nothing needed to be done regarding the locking, so I'm confused by this
comment.
I'm not entirely sure what you want since I feel like you are giving
conflicting direction, but I'm guessing you want the lock of the pm_lock
to be moved up to just under the mutex lock then?
--
Jeffrey Hugo
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
