Messages in this thread | | | Date | Fri, 6 Jan 2023 16:41:32 +0000 | Subject | Re: [PATCH v2 1/3] coresight: cti: Prevent negative values of enable count | From | Suzuki K Poulose <> |
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Hi James,
Thanks for fixing this.
On 06/01/2023 15:23, James Clark wrote: > Writing 0 to the enable control repeatedly results in a negative value > for enable_req_count. After this, writing 1 to the enable control > appears to not work until the count returns to positive. > > Change it so that it's impossible for enable_req_count to be < 0.
I prefer rephrasing the following :
> Returning an error will also allow us to decide whether to call > runtime_pm_put() or not in the following commit.
"Return an error to indicate the disable request was invalid"
and don't mention the forward dependency.
>
May be also add ?
Fixes: 835d722ba10a ("coresight: cti: Initial CoreSight CTI Driver")
> Signed-off-by: James Clark <james.clark@arm.com>
Rest looks fine to me.
Suzuki
> --- > drivers/hwtracing/coresight/coresight-cti-core.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c > index d2cf4f4848e1..838872f2484d 100644 > --- a/drivers/hwtracing/coresight/coresight-cti-core.c > +++ b/drivers/hwtracing/coresight/coresight-cti-core.c > @@ -151,9 +151,16 @@ static int cti_disable_hw(struct cti_drvdata *drvdata) > { > struct cti_config *config = &drvdata->config; > struct coresight_device *csdev = drvdata->csdev; > + int ret = 0; > > spin_lock(&drvdata->spinlock); > > + /* don't allow negative refcounts, return an error */ > + if (!atomic_read(&drvdata->config.enable_req_count)) { > + ret = -EINVAL; > + goto cti_not_disabled; > + } > + > /* check refcount - disable on 0 */ > if (atomic_dec_return(&drvdata->config.enable_req_count) > 0) > goto cti_not_disabled; > @@ -171,12 +178,12 @@ static int cti_disable_hw(struct cti_drvdata *drvdata) > coresight_disclaim_device_unlocked(csdev); > CS_LOCK(drvdata->base); > spin_unlock(&drvdata->spinlock); > - return 0; > + return ret; > > /* not disabled this call */ > cti_not_disabled: > spin_unlock(&drvdata->spinlock); > - return 0; > + return ret; > } > > void cti_write_single_reg(struct cti_drvdata *drvdata, int offset, u32 value)
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