locking/pvqspinlock: Use try_cmpxchg_acquire() in trylock_clear_pending()

Replace this pattern in trylock_clear_pending():

    cmpxchg_acquire(*ptr, old, new) == old

... with the simpler and faster:

    try_cmpxchg_acquire(*ptr, &old, new)

The x86 CMPXCHG instruction returns success in the ZF flag, so this change
saves a compare after the CMPXCHG.

Also change the return type of the function to bool and streamline
the control flow in the _Q_PENDING_BITS == 8 variant a bit.

No functional change intended.

Signed-off-by: Uros Bizjak <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Waiman Long <[email protected]>
Reviewed-by: Linus Torvalds <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions