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[v4,0/4] bus: mhi: host: Add lock to avoid race when ringing channel DB

Message ID 1699939661-7385-1-git-send-email-quic_qianyu@quicinc.com
Headers
Series bus: mhi: host: Add lock to avoid race when ringing channel DB |

Message

Qiang Yu Nov. 14, 2023, 5:27 a.m. UTC 
  1. We need a write lock in mhi_gen_tre otherwise there is race of the WP
used for ringing channel DB between mhi_queue and M0 transition.
2. We can not invoke local_bh_enable() when irqs are disabled, so move
read_lock_irqsave() under the mhi_gen_tre() since we add write_lock_bh() in
mhi_gen_tre().
3. Unlock xfer_cb to prevent potential lockup
4. After re-lock, check mhi channel state again to stop processing of a
disabled or stopped channel.  

v1 -> v2:
Added write_unlock_bh(&mhi_chan->lock) in mhi_gen_tre() before return
because of error process.

v2 -> v3:
1. split protecting WP and unlocking xfer_cb into two patches
2. Add a new patch to stop processing buffer and eventof a disabled or
stopped channel.

v3 -> v4:
1. Modify commit message
2. Add unlock operation before return error

Bhaumik Bhatt (1):
  bus: mhi: host: Add spinlock to protect WP access when queueing TREs

Hemant Kumar (1):
  bus: mhi: host: Take irqsave lock after TRE is generated

Qiang Yu (2):
  bus: mhi: host: Drop chan lock before queuing buffers
  bus: mhi: host: Avoid processing buffer and event of a disable channel

 drivers/bus/mhi/host/main.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)