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From:   "Matthew Wilcox (Oracle)" <willy@infradead.org>
To:     Kees Cook <keescook@chromium.org>, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
Cc:     "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        linux-kernel@vger.kernel.org
Subject: [PATCH 00/19] Enable -Wshadow=local for kernel/sched
Date:   Wed,  2 Mar 2022 04:34:32 +0000
Message-Id: <20220302043451.2441320-1-willy@infradead.org>
MIME-Version: 1.0
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I thought I'd choose one of the more core parts of the kernel to
demonstrate the value of -Wshadow.  It found two places where there are
shadowed variables that are at least confusing.  For all I know they're
buggy and my resolution of these warnings is wrong.

The first 12 patches just untangle the unclean uses of __ret in wait.h
& friends.  Then 4 patches to fix problems in headers that are noticed
by kernel/sched.  Two patches fix the two places in kernel/sched/
with shadowed variables and the final patch adds -Wshadow=local to
the Makefile.

I'm quite certain this patch series isn't going in as-is.  But maybe
it'll inspire some patches that can go in.

Matthew Wilcox (Oracle) (19):
  wait: Parameterize the return variable to ___wait_event()
  swait: Parameterize the return variable to __swait_event_timeout()
  swait: Parameterize the return variable to
    __swait_event_interruptible_timeout()
  swait: Parameterize the return variable to
    __swait_event_idle_timeout()
  wait: Parameterize the return variable to __wait_event_timeout()
  wait: Parameterize the return variable to
    __wait_event_freezable_timeout()
  wait: Parameterize the return variable to
    __wait_event_interruptible_timeout()
  wait: Parameterize the return variable to __wait_event_idle_timeout()
  wait: Parameterize the return variable to
    __wait_event_idle_exclusive_timeout()
  wait: Parameterize the return variable to
    __wait_event_killable_timeout()
  wait: Parameterize the return variable to
    __wait_event_lock_irq_timeout()
  wait_bit: Parameterize the return variable to
    __wait_var_event_timeout()
  Add UNIQUE_ID
  wait: Add a unique identifier to ___wait_event()
  x86: Use a unique identifier in __WARN_FLAGS()
  x86: Pass a unique identifier to __xchg_op()
  sched/rt: Rename a shadowed variable
  sched/topology: Rename the cpu parameter
  sched: Enable -Wshadow=local

 arch/x86/include/asm/bug.h     |   4 +-
 arch/x86/include/asm/cmpxchg.h |   6 +-
 include/linux/compiler.h       |   1 +
 include/linux/swait.h          |  24 ++--
 include/linux/wait.h           | 223 ++++++++++++++++-----------------
 include/linux/wait_bit.h       |   9 +-
 kernel/sched/Makefile          |   1 +
 kernel/sched/rt.c              |   4 +-
 kernel/sched/topology.c        |   6 +-
 9 files changed, 138 insertions(+), 140 deletions(-)

-- 
2.34.1