On 6/21/24 11:15, Bjorn Andersson wrote:
On Tue, Jun 18, 2024 at 09:13:05PM GMT, Sibi Sankar wrote:
The multiple BWMONv4 instances available on the X1E80100 SoC use the
same interrupt number. Mark them are shared to allow for re-use across
instances. Handle the ensuing race introduced by relying on bwmon_disable
In an effort to educate the reader, could you please describe what the
race condition is here.
It would also make sense to break this ("Handle...") into a separate
paragraph.
Ack, will make the changes in the next re-spin.
-Sibi
Regards,
Bjorn
to disable the interrupt and coupled with explicit request/free irqs.
Signed-off-by: Sibi Sankar <quic_sibis@xxxxxxxxxxx>
---
v2:
* Use explicit request/free irq and add comments regarding the race
introduced when adding the IRQF_SHARED flag. [Krzysztof/Dmitry]
drivers/soc/qcom/icc-bwmon.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/soc/qcom/icc-bwmon.c b/drivers/soc/qcom/icc-bwmon.c
index fb323b3364db..4a4e28b41509 100644
--- a/drivers/soc/qcom/icc-bwmon.c
+++ b/drivers/soc/qcom/icc-bwmon.c
@@ -781,9 +781,10 @@ static int bwmon_probe(struct platform_device *pdev)
bwmon->dev = dev;
bwmon_disable(bwmon);
- ret = devm_request_threaded_irq(dev, bwmon->irq, bwmon_intr,
- bwmon_intr_thread,
- IRQF_ONESHOT, dev_name(dev), bwmon);
+
+ /* SoCs with multiple cpu-bwmon instances can end up using a shared interrupt line */
+ ret = request_threaded_irq(bwmon->irq, bwmon_intr, bwmon_intr_thread,
+ IRQF_ONESHOT | IRQF_SHARED, dev_name(dev), bwmon);
if (ret)
return dev_err_probe(dev, ret, "failed to request IRQ\n");
@@ -798,6 +799,13 @@ static void bwmon_remove(struct platform_device *pdev)
struct icc_bwmon *bwmon = platform_get_drvdata(pdev);
bwmon_disable(bwmon);
+
+ /*
+ * Handle the race introduced, when dealing with multiple bwmon instances
+ * using a shared interrupt line, by relying on bwmon_disable to disable
+ * the interrupt and followed by an explicit free.
+ */
+ free_irq(bwmon->irq, bwmon);
}
static const struct icc_bwmon_data msm8998_bwmon_data = {
--
2.34.1
