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From:   Qiang Yu <quic_qianyu@quicinc.com>
To:     mani@kernel.org, quic_jhugo@quicinc.com
Cc:     mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, quic_cang@quicinc.com,
        quic_mrana@quicinc.com, Qiang Yu <quic_qianyu@quicinc.com>
Subject: [PATCH v5 0/2] bus: mhi: host: Add lock to avoid race when ringing channel DB
Date:   Mon, 11 Dec 2023 14:42:50 +0800
Message-Id: <1702276972-41296-1-git-send-email-quic_qianyu@quicinc.com>
Precedence: bulk


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

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

v4 -> v5:
1. Squash "protecting WP" and "Take irqsave lock" into one patch
2. Drop patch 3/4 of patch v4

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

Qiang Yu (1):
  bus: mhi: host: Drop chan lock before queuing buffers

 drivers/bus/mhi/host/main.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

-- 
2.7.4