[PATCH 8/9] firmware: arm_scmi: Unwind P2A receiver mailbox setup failure

[Sudeep Holla <sudeep.holla@kernel.org>]

mailbox_chan_setup() can request an additional P2A receiver channel after
successfully acquiring the primary P2A channel. If that later request
fails, the function returns immediately and leaves the primary channel
allocated.

Unwind the primary mailbox channel before returning the error so probe
deferral or other setup failures do not leave the channel busy for later
probe attempts.

Fixes: fa8b28ba22d9 ("firmware: arm_scmi: Add support for platform to agent channel completion")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
---
 drivers/firmware/arm_scmi/transports/mailbox.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_scmi/transports/mailbox.c b/drivers/firmware/arm_scmi/transports/mailbox.c
index 44d45ce838e5..f2bda95953d4 100644
--- a/drivers/firmware/arm_scmi/transports/mailbox.c
+++ b/drivers/firmware/arm_scmi/transports/mailbox.c
@@ -236,9 +236,10 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 		smbox->chan_platform_receiver = mbox_request_channel(cl, p2a_rx_chan);
 		if (IS_ERR(smbox->chan_platform_receiver)) {
 			ret = PTR_ERR(smbox->chan_platform_receiver);
+			smbox->chan_platform_receiver = NULL;
 			if (ret != -EPROBE_DEFER)
 				dev_err(cdev, "failed to request SCMI P2A Receiver mailbox\n");
-			return ret;
+			goto err_free_chan_receiver;
 		}
 	}
 
@@ -248,6 +249,8 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 
 	return 0;
 
+err_free_chan_receiver:
+	mbox_free_channel(smbox->chan_receiver);
 err_free_chan:
 	mbox_free_channel(smbox->chan);
 	return ret;

-- 
2.43.0