From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/7] stm class: Replace uuid_t with plain u8 uuid[16]
Date: Wed, 14 Apr 2021 20:47:48 +0300 [thread overview]
Message-ID: <YHcqxMLR44laX2PZ@smile.fi.intel.com> (raw)
In-Reply-To: <YHcnckePpKDujCU+@kroah.com>
On Wed, Apr 14, 2021 at 07:33:38PM +0200, Greg Kroah-Hartman wrote:
> On Wed, Apr 14, 2021 at 08:12:46PM +0300, Alexander Shishkin wrote:
> > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> >
> > It appears that uuid_t use in STM code abuses UUID API.
>
> How is it being abused?
We are using it against the buffer that is u8, and neither uuid_t nor guid_t.
> Moreover,
> > this type is only useful when we parse user input. Due to above
> > replace uuid_t with u8 uuid[16] and use uuid_t only when parse
> > user input.
> >
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> > ---
> > drivers/hwtracing/stm/p_sys-t.c | 16 ++++++++++------
> > 1 file changed, 10 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/hwtracing/stm/p_sys-t.c b/drivers/hwtracing/stm/p_sys-t.c
> > index 360b5c03df95..04d13b3785d3 100644
> > --- a/drivers/hwtracing/stm/p_sys-t.c
> > +++ b/drivers/hwtracing/stm/p_sys-t.c
> > @@ -76,7 +76,7 @@ enum sys_t_message_string_subtype {
> > MIPI_SYST_SEVERITY(MAX))
> >
> > struct sys_t_policy_node {
> > - uuid_t uuid;
> > + u8 uuid[UUID_SIZE];
>
> This feels wrong, what is wrong with the uuid_t type usage here?
Nothing, just will require additional export_uuid() / import_uuid() call.
> > bool do_len;
> > unsigned long ts_interval;
> > unsigned long clocksync_interval;
> > @@ -92,7 +92,7 @@ static void sys_t_policy_node_init(void *priv)
> > {
> > struct sys_t_policy_node *pn = priv;
> >
> > - generate_random_uuid(pn->uuid.b);
>
> Ok, that's not good, but that looks to be a flaw in the
> generate_random_uuid() api, not this driver implementation.
>
> I don't understand why this change is needed?
Using raw buffer APIs against uuid_t / guid_t.
We can import_uuid() first and call uuid_gen() against it. Will it work for
you?
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2021-04-14 17:48 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 17:12 [PATCH 0/7] stm class/intel_th: Updates for v5.13 Alexander Shishkin
2021-04-14 17:12 ` [PATCH 1/7] stm class: Remove an unused function Alexander Shishkin
2021-04-14 17:12 ` [PATCH 2/7] stm class: Replace uuid_t with plain u8 uuid[16] Alexander Shishkin
2021-04-14 17:33 ` Greg Kroah-Hartman
2021-04-14 17:47 ` Andy Shevchenko [this message]
2021-04-14 18:56 ` Greg Kroah-Hartman
2021-04-14 19:12 ` Andy Shevchenko
2021-04-14 19:14 ` Alexander Shishkin
2021-04-14 19:16 ` Andy Shevchenko
2021-04-15 8:34 ` Greg Kroah-Hartman
2021-04-15 8:48 ` Andy Shevchenko
2021-04-15 9:08 ` Greg Kroah-Hartman
2021-04-15 9:20 ` Alexander Shishkin
2021-04-14 17:12 ` [PATCH 3/7] intel_th: Constify all drvdata references Alexander Shishkin
2021-04-14 17:12 ` [PATCH 4/7] intel_th: Constify attribute_group structs Alexander Shishkin
2021-04-14 17:12 ` [PATCH 5/7] intel_th: Consistency and off-by-one fix Alexander Shishkin
2021-04-14 17:12 ` [PATCH 6/7] intel_th: pci: Add Rocket Lake CPU support Alexander Shishkin
2021-04-14 17:12 ` [PATCH 7/7] intel_th: pci: Add Alder Lake-M support Alexander Shishkin
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