net: jme: Replace link-change tasklet with work

The link change tasklet disables the tasklets for tx/rx processing while
upating hw parameters and then enables the tasklets again.

This update can also be pushed into a workqueue where it can be performed
in preemptible context. This allows tasklet_disable() to become sleeping.

Replace the linkch_task tasklet with a work.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210309084242.106288922@linutronix.de

drivers/net/ethernet/jme.c

@@ -1265,9 +1265,9 @@ jme_stop_shutdown_timer(struct jme_adapter *jme)
 	jwrite32f(jme, JME_APMC, apmc);
 }
 
-static void jme_link_change_tasklet(struct tasklet_struct *t)
+static void jme_link_change_work(struct work_struct *work)
 {
-	struct jme_adapter *jme = from_tasklet(jme, t, linkch_task);
+	struct jme_adapter *jme = container_of(work, struct jme_adapter, linkch_task);
 	struct net_device *netdev = jme->dev;
 	int rc;
 
@@ -1510,7 +1510,7 @@ jme_intr_msi(struct jme_adapter *jme, u32 intrstat)
 		 * all other events are ignored
 		 */
 		jwrite32(jme, JME_IEVE, intrstat);
-		tasklet_schedule(&jme->linkch_task);
+		schedule_work(&jme->linkch_task);
 		goto out_reenable;
 	}
 
@@ -1832,7 +1832,6 @@ jme_open(struct net_device *netdev)
 	jme_clear_pm_disable_wol(jme);
 	JME_NAPI_ENABLE(jme);
 
-	tasklet_setup(&jme->linkch_task, jme_link_change_tasklet);
 	tasklet_setup(&jme->txclean_task, jme_tx_clean_tasklet);
 	tasklet_setup(&jme->rxclean_task, jme_rx_clean_tasklet);
 	tasklet_setup(&jme->rxempty_task, jme_rx_empty_tasklet);
@@ -1920,7 +1919,7 @@ jme_close(struct net_device *netdev)
 
 	JME_NAPI_DISABLE(jme);
 
-	tasklet_kill(&jme->linkch_task);
+	cancel_work_sync(&jme->linkch_task);
 	tasklet_kill(&jme->txclean_task);
 	tasklet_kill(&jme->rxclean_task);
 	tasklet_kill(&jme->rxempty_task);
@@ -3035,6 +3034,7 @@ jme_init_one(struct pci_dev *pdev,
 	atomic_set(&jme->rx_empty, 1);
 
 	tasklet_setup(&jme->pcc_task, jme_pcc_tasklet);
+	INIT_WORK(&jme->linkch_task, jme_link_change_work);
 	jme->dpi.cur = PCC_P1;
 
 	jme->reg_ghc = 0;

drivers/net/ethernet/jme.h

@@ -411,7 +411,7 @@ struct jme_adapter {
 	struct tasklet_struct	rxempty_task;
 	struct tasklet_struct	rxclean_task;
 	struct tasklet_struct	txclean_task;
-	struct tasklet_struct	linkch_task;
+	struct work_struct	linkch_task;
 	struct tasklet_struct	pcc_task;
 	unsigned long		flags;
 	u32			reg_txcs;