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    Subject[patch 04/20] posix-timers: Cleanup comments about timer ID tracking
    Date
    Describe the hash table properly and remove the IDR leftover comments.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    ---
    kernel/time/posix-timers.c | 28 ++++++++--------------------
    1 file changed, 8 insertions(+), 20 deletions(-)

    --- a/kernel/time/posix-timers.c
    +++ b/kernel/time/posix-timers.c
    @@ -35,20 +35,17 @@
    #include "timekeeping.h"
    #include "posix-timers.h"

    -/*
    - * Management arrays for POSIX timers. Timers are now kept in static hash table
    - * with 512 entries.
    - * Timer ids are allocated by local routine, which selects proper hash head by
    - * key, constructed from current->signal address and per signal struct counter.
    - * This keeps timer ids unique per process, but now they can intersect between
    - * processes.
    - */
    +static struct kmem_cache *posix_timers_cache;

    /*
    - * Lets keep our timers in a slab cache :-)
    + * Timers are managed in a hash table for lockless lookup. The hash key is
    + * constructed from current::signal and the timer ID and the timer is
    + * matched against current::signal and the timer ID when walking the hash
    + * bucket list.
    + *
    + * This allows checkpoint/restore to reconstruct the exact timer IDs for
    + * a process.
    */
    -static struct kmem_cache *posix_timers_cache;
    -
    static DEFINE_HASHTABLE(posix_timers_hashtable, 9);
    static DEFINE_SPINLOCK(hash_lock);

    @@ -66,15 +63,6 @@ static const struct k_clock clock_realti
    #endif

    /*
    - * The timer ID is turned into a timer address by idr_find().
    - * Verifying a valid ID consists of:
    - *
    - * a) checking that idr_find() returns other than -1.
    - * b) checking that the timer id matches the one in the timer itself.
    - * c) that the timer owner is in the callers thread group.
    - */
    -
    -/*
    * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
    * to implement others. This structure defines the various
    * clocks.
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