Now that mode is in struct coresight_device, this pattern can be wrapped in a helper.
Signed-off-by: James Clark james.clark@arm.com --- drivers/hwtracing/coresight/coresight-etm3x-core.c | 8 +++----- drivers/hwtracing/coresight/coresight-etm4x-core.c | 8 +++----- drivers/hwtracing/coresight/coresight-stm.c | 8 +++----- include/linux/coresight.h | 11 +++++++++++ 4 files changed, 20 insertions(+), 15 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c index a8be115636f0..ce2b3ed90fb9 100644 --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c @@ -556,14 +556,12 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event, enum cs_mode mode) { int ret; - u32 val; struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
- val = local_cmpxchg(&drvdata->csdev->mode, CS_MODE_DISABLED, mode); - - /* Someone is already using the tracer */ - if (val) + if (!coresight_take_mode(csdev, mode)) { + /* Someone is already using the tracer */ return -EBUSY; + }
switch (mode) { case CS_MODE_SYSFS: diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 3480b563981c..8fca7fc379e6 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -840,13 +840,11 @@ static int etm4_enable(struct coresight_device *csdev, struct perf_event *event, enum cs_mode mode) { int ret; - u32 val;
- val = local_cmpxchg(&csdev->mode, CS_MODE_DISABLED, mode); - - /* Someone is already using the tracer */ - if (val) + if (!coresight_take_mode(csdev, mode)) { + /* Someone is already using the tracer */ return -EBUSY; + }
switch (mode) { case CS_MODE_SYSFS: diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c index af9b21224246..80fed4c377f1 100644 --- a/drivers/hwtracing/coresight/coresight-stm.c +++ b/drivers/hwtracing/coresight/coresight-stm.c @@ -193,17 +193,15 @@ static void stm_enable_hw(struct stm_drvdata *drvdata) static int stm_enable(struct coresight_device *csdev, struct perf_event *event, enum cs_mode mode) { - u32 val; struct stm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
if (mode != CS_MODE_SYSFS) return -EINVAL;
- val = local_cmpxchg(&csdev->mode, CS_MODE_DISABLED, mode); - - /* Someone is already using the tracer */ - if (val) + if (!coresight_take_mode(csdev, mode)) { + /* Someone is already using the tracer */ return -EBUSY; + }
pm_runtime_get_sync(csdev->dev.parent);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h index c5be46d7f85c..175d184b3a1b 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -580,6 +580,17 @@ static inline bool coresight_is_percpu_sink(struct coresight_device *csdev) (csdev->subtype.sink_subtype == CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM); }
+/* + * Atomically try to take the device and set a new mode. Returns true on + * success, false if the device is already taken by someone else. + */ +static inline bool coresight_take_mode(struct coresight_device *csdev, + enum cs_mode new_mode) +{ + return local_cmpxchg(&csdev->mode, CS_MODE_DISABLED, new_mode) == + CS_MODE_DISABLED; +} + extern struct coresight_device * coresight_register(struct coresight_desc *desc); extern void coresight_unregister(struct coresight_device *csdev);