[PATCH 00/19] Enable -Wshadow=local for kernel/sched

From: Matthew Wilcox (Oracle)
Date: Tue Mar 01 2022 - 23:35:55 EST


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(-)

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2.34.1