diff mbox series

[net,06/13] can: m_can: Do not cancel timer from within timer

Message ID 20240829192947.1186760-7-mkl@pengutronix.de (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series [net,01/13] can: bcm: Remove proc entry when dev is unregistered. | expand

Checks

Context Check Description
netdev/series_format success Pull request is its own cover letter
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 16 this patch: 16
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers fail 3 blamed authors not CCed: tony@atomide.com jm@ti.com horms@kernel.org; 7 maintainers not CCed: pabeni@redhat.com rcsekar@samsung.com tony@atomide.com horms@kernel.org mailhol.vincent@wanadoo.fr edumazet@google.com jm@ti.com
netdev/build_clang success Errors and warnings before: 16 this patch: 16
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 16 this patch: 16
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 103 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-08-30--06-00 (tests: 714)

Commit Message

Marc Kleine-Budde Aug. 29, 2024, 7:20 p.m. UTC 
From: Markus Schneider-Pargmann <msp@baylibre.com>

On setups without interrupts, the interrupt handler is called from a
timer callback. For non-peripheral receives napi is scheduled,
interrupts are disabled and the timer is canceled with a blocking call.
In case of an error this can happen as well.

Check if napi is scheduled in the timer callback after the interrupt
handler executed. If napi is scheduled, the timer is disabled. It will
be reenabled by m_can_poll().

Return error values from the interrupt handler so that interrupt threads
and timer callback can deal differently with it. In case of the timer
we only disable the timer. The rest will be done when stopping the
interface.

Fixes: b382380c0d2d ("can: m_can: Add hrtimer to generate software interrupt")
Fixes: a163c5761019 ("can: m_can: Start/Cancel polling timer together with interrupts")
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Link: https://lore.kernel.org/all/20240805183047.305630-5-msp@baylibre.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/m_can/m_can.c | 57 ++++++++++++++++++++++++++---------
 1 file changed, 42 insertions(+), 15 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index a37ed376de9b..5228304779f1 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -487,7 +487,7 @@  static inline void m_can_disable_all_interrupts(struct m_can_classdev *cdev)
 
 	if (!cdev->net->irq) {
 		dev_dbg(cdev->dev, "Stop hrtimer\n");
-		hrtimer_cancel(&cdev->hrtimer);
+		hrtimer_try_to_cancel(&cdev->hrtimer);
 	}
 }
 
@@ -1201,11 +1201,15 @@  static void m_can_coalescing_update(struct m_can_classdev *cdev, u32 ir)
 			      HRTIMER_MODE_REL);
 }
 
-static irqreturn_t m_can_isr(int irq, void *dev_id)
+/* This interrupt handler is called either from the interrupt thread or a
+ * hrtimer. This has implications like cancelling a timer won't be possible
+ * blocking.
+ */
+static int m_can_interrupt_handler(struct m_can_classdev *cdev)
 {
-	struct net_device *dev = (struct net_device *)dev_id;
-	struct m_can_classdev *cdev = netdev_priv(dev);
+	struct net_device *dev = cdev->net;
 	u32 ir;
+	int ret;
 
 	if (pm_runtime_suspended(cdev->dev))
 		return IRQ_NONE;
@@ -1232,11 +1236,9 @@  static irqreturn_t m_can_isr(int irq, void *dev_id)
 			m_can_disable_all_interrupts(cdev);
 			napi_schedule(&cdev->napi);
 		} else {
-			int pkts;
-
-			pkts = m_can_rx_handler(dev, NAPI_POLL_WEIGHT, ir);
-			if (pkts < 0)
-				goto out_fail;
+			ret = m_can_rx_handler(dev, NAPI_POLL_WEIGHT, ir);
+			if (ret < 0)
+				return ret;
 		}
 	}
 
@@ -1254,8 +1256,9 @@  static irqreturn_t m_can_isr(int irq, void *dev_id)
 	} else  {
 		if (ir & (IR_TEFN | IR_TEFW)) {
 			/* New TX FIFO Element arrived */
-			if (m_can_echo_tx_event(dev) != 0)
-				goto out_fail;
+			ret = m_can_echo_tx_event(dev);
+			if (ret != 0)
+				return ret;
 		}
 	}
 
@@ -1263,16 +1266,31 @@  static irqreturn_t m_can_isr(int irq, void *dev_id)
 		can_rx_offload_threaded_irq_finish(&cdev->offload);
 
 	return IRQ_HANDLED;
+}
 
-out_fail:
-	m_can_disable_all_interrupts(cdev);
-	return IRQ_HANDLED;
+static irqreturn_t m_can_isr(int irq, void *dev_id)
+{
+	struct net_device *dev = (struct net_device *)dev_id;
+	struct m_can_classdev *cdev = netdev_priv(dev);
+	int ret;
+
+	ret =  m_can_interrupt_handler(cdev);
+	if (ret < 0) {
+		m_can_disable_all_interrupts(cdev);
+		return IRQ_HANDLED;
+	}
+
+	return ret;
 }
 
 static enum hrtimer_restart m_can_coalescing_timer(struct hrtimer *timer)
 {
 	struct m_can_classdev *cdev = container_of(timer, struct m_can_classdev, hrtimer);
 
+	if (cdev->can.state == CAN_STATE_BUS_OFF ||
+	    cdev->can.state == CAN_STATE_STOPPED)
+		return HRTIMER_NORESTART;
+
 	irq_wake_thread(cdev->net->irq, cdev->net);
 
 	return HRTIMER_NORESTART;
@@ -1973,8 +1991,17 @@  static enum hrtimer_restart hrtimer_callback(struct hrtimer *timer)
 {
 	struct m_can_classdev *cdev = container_of(timer, struct
 						   m_can_classdev, hrtimer);
+	int ret;
 
-	m_can_isr(0, cdev->net);
+	if (cdev->can.state == CAN_STATE_BUS_OFF ||
+	    cdev->can.state == CAN_STATE_STOPPED)
+		return HRTIMER_NORESTART;
+
+	ret = m_can_interrupt_handler(cdev);
+
+	/* On error or if napi is scheduled to read, stop the timer */
+	if (ret < 0 || napi_is_scheduled(&cdev->napi))
+		return HRTIMER_NORESTART;
 
 	hrtimer_forward_now(timer, ms_to_ktime(HRTIMER_POLL_INTERVAL_MS));