Re: [PATCH] bus: mhi: ep: Change state_lock to mutex

[Jeffrey Hugo]

On 1/23/2023 12:50 AM, Manivannan Sadhasivam wrote:
> state_lock, the spinlock type is meant to protect race against concurrent
> MHI state transitions. In mhi_ep_set_m0_state(), while the state_lock is
> being held, the channels are resumed in mhi_ep_resume_channels() if the
> previous state was M3. This causes sleeping in atomic bug, since
> mhi_ep_resume_channels() use mutex internally.
>
> Since the state_lock is supposed to be held throughout the state change,
> it is not ideal to drop the lock before calling mhi_ep_resume_channels().
> So to fix this issue, let's change the type of state_lock to mutex. This
> would also allow holding the lock throughout all state transitions thereby
> avoiding any potential race.
>
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.19
> Fixes: e4b7b5f0f30a ("bus: mhi: ep: Add support for suspending and resuming channels")
> Reported-by: Dan Carpenter <error27@xxxxxxxxx>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>

Looks sane.
Reviewed-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>