linux-kernel - [PATCH v6 8/8] bus: mhi: core: Do not clear channel context more than once

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Date:   Thu,  4 Feb 2021 12:28:06 -0800
From:   Bhaumik Bhatt <bbhatt@...eaurora.org>
To:     manivannan.sadhasivam@...aro.org
Cc:     linux-arm-msm@...r.kernel.org, hemantk@...eaurora.org,
        jhugo@...eaurora.org, linux-kernel@...r.kernel.org,
        loic.poulain@...aro.org, Bhaumik Bhatt <bbhatt@...eaurora.org>
Subject: [PATCH v6 8/8] bus: mhi: core: Do not clear channel context more than once

Clearing a channel context can happen twice if the client driver
unprepares and reset the channels from the remove() callback from
a controller requested MHI power down sequence. If there are
multiple attempts at calling the mhi_free_coherent() API, we see
kernel warnings such as "trying to free invalid coherent area".
Example for one such client is the QRTR MHI driver. Avoid these
warnings by skipping mhi_deinit_chan_ctxt() API call and prevent
extra work from MHI as the channels are already disabled.

Signed-off-by: Bhaumik Bhatt <bbhatt@...eaurora.org>
---
 drivers/bus/mhi/core/init.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 30eef19..272f350 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -1314,6 +1314,7 @@ static int mhi_driver_remove(struct device *dev)

 		if ((ch_state[dir] == MHI_CH_STATE_ENABLED ||
 		     ch_state[dir] == MHI_CH_STATE_STOP) &&
+		    mhi_chan->ch_state != MHI_CH_STATE_DISABLED &&
 		    !mhi_chan->offload_ch)
 			mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);

-- 
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