Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
42 lines
640 B
Plaintext
42 lines
640 B
Plaintext
C RM-fixed
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(*
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* Result: Never
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*
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* This litmus test demonstrates that the old "roach motel" approach
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* to locking, where code can be freely moved into critical sections,
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* cannot be used in the Linux kernel.
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*)
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{
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int x;
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atomic_t y;
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}
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P0(int *x, atomic_t *y, spinlock_t *lck)
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{
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int r2;
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spin_lock(lck);
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r2 = atomic_inc_return(y);
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WRITE_ONCE(*x, 1);
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spin_unlock(lck);
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}
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P1(int *x, atomic_t *y, spinlock_t *lck)
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{
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int r0;
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int r1;
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int r2;
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r0 = READ_ONCE(*x);
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r1 = READ_ONCE(*x);
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spin_lock(lck);
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r2 = atomic_inc_return(y);
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spin_unlock(lck);
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}
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locations [x;0:r2;1:r0;1:r1;1:r2]
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filter (1:r0=0 /\ 1:r1=1)
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exists (1:r2=1)
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