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To:     'Thomas Gleixner' <tglx@linutronix.de>,
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CC:     "Kani, Toshi" <toshi.kani@hpe.com>
Subject: Is CLOCKS_MASK macro obsolete?
Thread-Topic: Is CLOCKS_MASK macro obsolete?
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Date:   Thu, 14 Oct 2021 23:46:11 +0000
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The CLOCKS_MASK macro in include/uapi/linux/time.h seems broken; it's ORing=
 together
two numbered values, one of which is 0. Perhaps these clock IDs started as =
a bitmask?
CLOCKS_MASK doesn't appear to be used anywhere in the kernel; nor does the =
adjacent=20
CLOCKS_MONO.

Should those macros be deleted?

Excerpt:
#define CLOCK_REALTIME                  0
#define CLOCK_MONOTONIC                 1
#define CLOCK_PROCESS_CPUTIME_ID        2
#define CLOCK_THREAD_CPUTIME_ID         3
#define CLOCK_MONOTONIC_RAW             4
#define CLOCK_REALTIME_COARSE           5
#define CLOCK_MONOTONIC_COARSE          6
#define CLOCK_BOOTTIME                  7
#define CLOCK_REALTIME_ALARM            8
#define CLOCK_BOOTTIME_ALARM            9
/*
 * The driver implementing this got removed. The clock ID is kept as a
 * place holder. Do not reuse!
 */
#define CLOCK_SGI_CYCLE                 10
#define CLOCK_TAI                       11

#define MAX_CLOCKS                      16
#define CLOCKS_MASK                     (CLOCK_REALTIME | CLOCK_MONOTONIC)
#define CLOCKS_MONO                     CLOCK_MONOTONIC