media: cec: safely unhook lists in cec_data

smatch warns about data->list not being removed from list:

drivers/media/cec/core/cec-adap.c:926 cec_transmit_msg_fh() warn: '&data->list' not removed from list

It is a false warning, but it doesn't hurt to make the code more robust
and safely unhook data->list and data->xfer_list together with a WARN_ON
if this is actually ever needed (this really shouldn't happen).

Note that fixing the data->list warning just replaced it with a new similar
warning for data->xfer_list, so both needed to be addressed.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/cec/core/cec-adap.c b/drivers/media/cec/core/cec-adap.c
index 79fa36de8a04a936249d7383751bc853cefd8103..da73eb50cce2faf4bff09d78b2c4c28dd2a618dd 100644 (file)
--- a/drivers/media/cec/core/cec-adap.c
+++ b/drivers/media/cec/core/cec-adap.c
@@ -342,7 +342,7 @@ static void cec_data_completed(struct cec_data *data)
         * Without that we would be referring to a closed filehandle.
         */
        if (data->fh)
-               list_del(&data->xfer_list);
+               list_del_init(&data->xfer_list);
 
        if (data->blocking) {
                /*
@@ -898,6 +898,8 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
 
        if (fh)
                list_add_tail(&data->xfer_list, &fh->xfer_list);
+       else
+               INIT_LIST_HEAD(&data->xfer_list);
 
        list_add_tail(&data->list, &adap->transmit_queue);
        adap->transmit_queue_sz++;
@@ -923,6 +925,10 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
 
        /* The transmit completed (possibly with an error) */
        *msg = data->msg;
+       if (WARN_ON(!list_empty(&data->list)))
+               list_del(&data->list);
+       if (WARN_ON(!list_empty(&data->xfer_list)))
+               list_del(&data->xfer_list);
        kfree(data);
        return 0;
 }

diff --git a/drivers/media/cec/core/cec-api.c b/drivers/media/cec/core/cec-api.c
index 769e6b4cddce3449323a69de376f062485cf0b64..0edb7142afdb8fdcc1df25c8cb0f028b92ba642e 100644 (file)
--- a/drivers/media/cec/core/cec-api.c
+++ b/drivers/media/cec/core/cec-api.c
@@ -669,7 +669,7 @@ static int cec_release(struct inode *inode, struct file *filp)
 
                data->blocking = false;
                data->fh = NULL;
-               list_del(&data->xfer_list);
+               list_del_init(&data->xfer_list);
        }
        mutex_unlock(&adap->lock);
        while (!list_empty(&fh->msgs)) {