can: mcp251x: fix resume from sleep before interface was brought up

Since 8ce8c0abcba3 the driver queues work via priv->restart_work when
resuming after suspend, even when the interface was not previously
enabled. This causes a null dereference error as the workqueue is only
allocated and initialized in mcp251x_open().

To fix this we move the workqueue init to mcp251x_can_probe() as there
is no reason to do it later and repeat it whenever mcp251x_open() is
called.

Fixes: 8ce8c0abcba3 ("can: mcp251x: only reset hardware as required")
Link: https://lore.kernel.org/r/17d5d714-b468-482f-f37a-482e3d6df84e@kontron.de
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[mkl: fix error handling in mcp251x_stop()]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index 492f1bc..173c661 100644 (file)
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -956,8 +956,6 @@ static int mcp251x_stop(struct net_device *net)
 
        priv->force_quit = 1;
        free_irq(spi->irq, priv);
-       destroy_workqueue(priv->wq);
-       priv->wq = NULL;
 
        mutex_lock(&priv->mcp_lock);
 
@@ -1224,24 +1222,15 @@ static int mcp251x_open(struct net_device *net)
                goto out_close;
        }
 
-       priv->wq = alloc_workqueue("mcp251x_wq", WQ_FREEZABLE | WQ_MEM_RECLAIM,
-                                  0);
-       if (!priv->wq) {
-               ret = -ENOMEM;
-               goto out_clean;
-       }
-       INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);
-       INIT_WORK(&priv->restart_work, mcp251x_restart_work_handler);
-
        ret = mcp251x_hw_wake(spi);
        if (ret)
-               goto out_free_wq;
+               goto out_free_irq;
        ret = mcp251x_setup(net, spi);
        if (ret)
-               goto out_free_wq;
+               goto out_free_irq;
        ret = mcp251x_set_normal_mode(spi);
        if (ret)
-               goto out_free_wq;
+               goto out_free_irq;
 
        can_led_event(net, CAN_LED_EVENT_OPEN);
 
@@ -1250,9 +1239,7 @@ static int mcp251x_open(struct net_device *net)
 
        return 0;
 
-out_free_wq:
-       destroy_workqueue(priv->wq);
-out_clean:
+out_free_irq:
        free_irq(spi->irq, priv);
        mcp251x_hw_sleep(spi);
 out_close:
@@ -1373,6 +1360,15 @@ static int mcp251x_can_probe(struct spi_device *spi)
        if (ret)
                goto out_clk;
 
+       priv->wq = alloc_workqueue("mcp251x_wq", WQ_FREEZABLE | WQ_MEM_RECLAIM,
+                                  0);
+       if (!priv->wq) {
+               ret = -ENOMEM;
+               goto out_clk;
+       }
+       INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);
+       INIT_WORK(&priv->restart_work, mcp251x_restart_work_handler);
+
        priv->spi = spi;
        mutex_init(&priv->mcp_lock);
 
@@ -1417,6 +1413,8 @@ static int mcp251x_can_probe(struct spi_device *spi)
        return 0;
 
 error_probe:
+       destroy_workqueue(priv->wq);
+       priv->wq = NULL;
        mcp251x_power_enable(priv->power, 0);
 
 out_clk:
@@ -1438,6 +1436,9 @@ static int mcp251x_can_remove(struct spi_device *spi)
 
        mcp251x_power_enable(priv->power, 0);
 
+       destroy_workqueue(priv->wq);
+       priv->wq = NULL;
+
        clk_disable_unprepare(priv->clk);
 
        free_candev(net);