[PATCH 3.16 362/366] net: ethernet: ti: cpdma: correct error handling for chan create

[Ben Hutchings <ben@xxxxxxxxxxxxxxx>]

3.16.60-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>

commit 8a83c5d7969b8433584e3cf658a8d76c4dc37f4d upstream.

It's not correct to return NULL when that is actually an error and
function returns errors in any other wrong case. In the same time,
the cpsw driver and davinci emac doesn't check error case while
creating channel and it can miss actual error. Also remove WARNs
replacing them on dev_err msgs.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
Reviewed-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.16:
 - Channel pointers are stored in different fields
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/ti/cpsw.c          | 12 +++++++++---
 drivers/net/ethernet/ti/davinci_cpdma.c |  2 +-
 drivers/net/ethernet/ti/davinci_emac.c  | 11 +++++++++--
 3 files changed, 19 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -2216,12 +2216,17 @@ static int cpsw_probe(struct platform_de
 
 	priv->txch = cpdma_chan_create(priv->dma, tx_chan_num(0),
 				       cpsw_tx_handler);
+	if (IS_ERR(priv->txch)) {
+		dev_err(priv->dev, "error initializing tx dma channel\n");
+		ret = PTR_ERR(priv->txch);
+		goto clean_dma_ret;
+	}
+
 	priv->rxch = cpdma_chan_create(priv->dma, rx_chan_num(0),
 				       cpsw_rx_handler);
-
-	if (WARN_ON(!priv->txch || !priv->rxch)) {
-		dev_err(priv->dev, "error initializing dma channels\n");
-		ret = -ENOMEM;
+	if (IS_ERR(priv->rxch)) {
+		dev_err(priv->dev, "error initializing rx dma channel\n");
+		ret = PTR_ERR(priv->rxch);
 		goto clean_dma_ret;
 	}
 
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -503,7 +503,7 @@ struct cpdma_chan *cpdma_chan_create(str
 	unsigned long flags;
 
 	if (__chan_linear(chan_num) >= ctlr->num_chan)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	chan = devm_kzalloc(ctlr->dev, sizeof(*chan), GFP_KERNEL);
 	if (!chan)
--- a/drivers/net/ethernet/ti/davinci_emac.c
+++ b/drivers/net/ethernet/ti/davinci_emac.c
@@ -1951,10 +1951,17 @@ static int davinci_emac_probe(struct pla
 
 	priv->txchan = cpdma_chan_create(priv->dma, tx_chan_num(EMAC_DEF_TX_CH),
 				       emac_tx_handler);
+	if (IS_ERR(priv->txchan)) {
+		dev_err(&pdev->dev, "error initializing tx dma channel\n");
+		rc = PTR_ERR(priv->txchan);
+		goto no_cpdma_chan;
+	}
+
 	priv->rxchan = cpdma_chan_create(priv->dma, rx_chan_num(EMAC_DEF_RX_CH),
 				       emac_rx_handler);
-	if (WARN_ON(!priv->txchan || !priv->rxchan)) {
-		rc = -ENOMEM;
+	if (IS_ERR(priv->rxchan)) {
+		dev_err(&pdev->dev, "error initializing rx dma channel\n");
+		rc = PTR_ERR(priv->rxchan);
 		goto no_cpdma_chan;
 	}