Re: [PATCH v3 02/13] coresight: etb10: Fix handling of perf mode
From: Suzuki K Poulose
Date: Tue Jul 31 2018 - 17:32:06 EST
On 07/31/2018 06:07 PM, Mathieu Poirier wrote:
Hello,
On Thu, Jul 26, 2018 at 01:54:40PM +0100, Suzuki K Poulose wrote:
If the ETB is already enabled in sysfs mode, the ETB reports
success even if a perf mode is requested. Fix this by checking
the requested mode.
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
drivers/hwtracing/coresight/coresight-etb10.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 306119e..e5808fd 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -148,8 +148,12 @@ static int etb_enable(struct coresight_device *csdev, u32 mode)
return -EBUSY;
/* Nothing to do, the tracer is already enabled. */
- if (val == CS_MODE_SYSFS)
- goto out;
+ if (val == CS_MODE_SYSFS) {
+ if (mode == CS_MODE_SYSFS)
+ goto out;
+ else
+ return -EBUSY;
+ }
How about:
if (val == CS_MODE_PERF)
return -EBUSY;
+ /* Don't let perf disturb sysFS sessions */
+ if (val == CS_MODE_SYSFS && mode = CS_MODE_PERF)
+ return -EBUSY;
+
/* Nothing to do, the tracer is already enabled. */
if (val == CS_MODE_SYSFS)
goto out;
I just find it more readable that way.
Sure, thats fine by me.
Cheers
Suzuki