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coresight/ultrasoc: change smb_drv_data spinlock's type to raw_spinlock_t

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In ultrasoc-smb drivers, smb_drv_data->spinlock can be held
during __schedule() by perf_event_task_sched_out()/in().

Since smb__drv_data->spinlock type is spinlock_t and
perf_event_task_sched_out()/in() is called after acquiring rq_lock,
which is raw_spinlock_t (an unsleepable lock),
this poses an issue in PREEMPT_RT kernel where spinlock_t is sleepable.

To address this, change type smb_drv_data->spinlock in ultrasoc-smb drivers,
which can be called by perf_event_task_sched_out()/in(),
from spinlock_t to raw_spinlock_t.

Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250306121110.1647948-10-yeoreum.yun@arm.com
This commit is contained in:
Yeoreum Yun 2025-03-06 12:11:10 +00:00 committed by Suzuki K Poulose
parent db11f75bc2
commit d11eb31db2
2 changed files with 7 additions and 7 deletions
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12
drivers/hwtracing/coresight/ultrasoc-smb.c
View File

@ -98,7 +98,7 @@ static int smb_open(struct inode *inode, struct file *file)
struct smb_drv_data *drvdata = container_of(file->private_data,
struct smb_drv_data, miscdev);
guard(spinlock)(&drvdata->spinlock);
guard(raw_spinlock)(&drvdata->spinlock);
if (drvdata->reading)
return -EBUSY;
@ -152,7 +152,7 @@ static int smb_release(struct inode *inode, struct file *file)
struct smb_drv_data *drvdata = container_of(file->private_data,
struct smb_drv_data, miscdev);
guard(spinlock)(&drvdata->spinlock);
guard(raw_spinlock)(&drvdata->spinlock);
drvdata->reading = false;
return 0;
@ -245,7 +245,7 @@ static int smb_enable(struct coresight_device *csdev, enum cs_mode mode,
struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
int ret = 0;
guard(spinlock)(&drvdata->spinlock);
guard(raw_spinlock)(&drvdata->spinlock);
/* Do nothing, the trace data is reading by other interface now */
if (drvdata->reading)
@ -280,7 +280,7 @@ static int smb_disable(struct coresight_device *csdev)
{
struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
guard(spinlock)(&drvdata->spinlock);
guard(raw_spinlock)(&drvdata->spinlock);
if (drvdata->reading)
return -EBUSY;
@ -378,7 +378,7 @@ static unsigned long smb_update_buffer(struct coresight_device *csdev,
if (!buf)
return 0;
guard(spinlock)(&drvdata->spinlock);
guard(raw_spinlock)(&drvdata->spinlock);
/* Don't do anything if another tracer is using this sink. */
if (csdev->refcnt != 1)
@ -563,7 +563,7 @@ static int smb_probe(struct platform_device *pdev)
smb_reset_buffer(drvdata);
platform_set_drvdata(pdev, drvdata);
spin_lock_init(&drvdata->spinlock);
raw_spin_lock_init(&drvdata->spinlock);
drvdata->pid = -1;
ret = smb_register_sink(pdev, drvdata);

2
drivers/hwtracing/coresight/ultrasoc-smb.h
View File

@ -115,7 +115,7 @@ struct smb_drv_data {
struct coresight_device *csdev;
struct smb_data_buffer sdb;
struct miscdevice miscdev;
spinlock_t spinlock;
raw_spinlock_t spinlock;
bool reading;
pid_t pid;
};