linux-kernel - [char-misc-next 2/2] mei: cleanup status before client dma setup call

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Date:   Thu, 23 Dec 2021 11:47:05 +0200
From:   Tomas Winkler <tomas.winkler@...el.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Alexander Usyskin <alexander.usyskin@...el.com>,
        Vitaly Lubart <vitaly.lubart@...el.com>,
        linux-kernel@...r.kernel.org,
        Tomas Winkler <tomas.winkler@...el.com>
Subject: [char-misc-next 2/2] mei: cleanup status before client dma setup call

From: Alexander Usyskin <alexander.usyskin@...el.com>

The upper layer may retry call to mei_cl_dma_alloc_and_map(),
in that case the client status may be non-zero after the previous call
and the wait condition will be true immediately.
Set cl->status to zero to allow waiting for an actual result
from the firmware.

Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
---
 drivers/misc/mei/client.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 96f4e59c32a5..22be86a205bf 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -2327,6 +2327,8 @@ int mei_cl_dma_alloc_and_map(struct mei_cl *cl, const struct file *fp,
 		list_move_tail(&cb->list, &dev->ctrl_rd_list);
 	}
 
+	cl->status = 0;
+
 	mutex_unlock(&dev->device_lock);
 	wait_event_timeout(cl->wait,
 			   cl->dma_mapped || cl->status,
@@ -2404,6 +2406,8 @@ int mei_cl_dma_unmap(struct mei_cl *cl, const struct file *fp)
 		list_move_tail(&cb->list, &dev->ctrl_rd_list);
 	}
 
+	cl->status = 0;
+
 	mutex_unlock(&dev->device_lock);
 	wait_event_timeout(cl->wait,
 			   !cl->dma_mapped || cl->status,
-- 
2.31.1