Messages in this thread | | | Date | Fri, 4 Aug 2023 09:55:04 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH] x86/microcode: Remove microcode_mutex. |
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On 2023-08-03 14:15:13 [-0700], Sohil Mehta wrote: > Nit: The full stop at the end is not needed. > > On 8/3/2023 1:32 AM, Sebastian Andrzej Siewior wrote: > > microcode_mutex is only used by reload_store(). It has a comment saying > > "to synchronize with each other". This probably means the sysfs > > interface vs the legacy interface which was removed in commit > > 181b6f40e9ea8 ("x86/microcode: Rip out the OLD_INTERFACE"). > > > > There is also commit b6f86689d5b7 ("x86/microcode: Rip out the subsys > interface gunk") which last year removed another usage of microcode_mutex.
Okay.
> > The sysfs interface does not need additional synchronisation vs itself > > because it is provided as kernfs_ops::mutex which is acquired in > > kernfs_fop_write_iter(). > > > > Remove superfluous microcode_mutex. > > I agree, the current usage does look unnecessary. > > Maybe reword the commit message to say that after these two Rip outs > there are no of *other* usages of microcode_mutex to synchronize with?
Okay.
> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > > --- > > This poped up as "defined but not used" on RT builds without > > CONFIG_MICROCODE_LATE_LOADING enabled. > > This issue has been raised a couple of times recently but the > justification has been deemed insufficient since it can't be reproduced > with a .config file.
The PREEMPT_RT's implementation of struct mutex is different which makes it easier for the compiler to spot an used mutex. The !RT's implementation has list_head pointing to the mutex as part of MUTEX_INIT which marks the variable as used.
> See: > https://lore.kernel.org/lkml/20230324114720.1756466-1-john.ogness@linutronix.de/ > > and > > https://lore.kernel.org/lkml/20230522062713.427998-1-christian.gmeiner@gmail.com/ > > However, your current justification of not needing the mutex itself > seems reasonable to me.
So everyone tried to move it but me…
… > The code changes look fine to me. > > You can also add below to the patch.
Will do.
Sebastian
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