From mboxrd@z Thu Jan 1 00:00:00 1970 From: suzuki.poulose@arm.com (Suzuki K Poulose) Date: Tue, 31 Jul 2018 22:32:39 +0100 Subject: [PATCH v3 02/13] coresight: etb10: Fix handling of perf mode In-Reply-To: <20180731170731.GA11692@xps15> References: <1532609691-16863-1-git-send-email-suzuki.poulose@arm.com> <1532609691-16863-3-git-send-email-suzuki.poulose@arm.com> <20180731170731.GA11692@xps15> Message-ID: <7b311596-025a-f4f4-1859-6f3531258b75@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 >> Signed-off-by: Suzuki K Poulose >> --- >> 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