• Ingo Molnar's avatar
    sched/wait: Standardize internal naming of wait-queue entries · 50816c48
    Ingo Molnar authored
    So the various wait-queue entry variables in include/linux/wait.h
    and kernel/sched/wait.c are named in a colorfully inconsistent
    way:
    
    	wait_queue_entry_t *wait
    	wait_queue_entry_t *__wait	(even in plain C code!)
    	wait_queue_entry_t *q		(!)
    	wait_queue_entry_t *new		(making anyone who knows C++ cringe)
    	wait_queue_entry_t *old
    
    I think part of the reason for the inconsistency is the constant
    apparent confusion about what a wait queue 'head' versus 'entry' is.
    
    ( Some of the documentation talks about a 'wait descriptor', which is
      the wait-queue entry itself - further adding to the confusion. )
    
    The most common name is 'wait', but that in itself is somewhat
    ambiguous as well, as it does not really make it clear whether
    it's a wait-queue entry or head.
    
    To improve all this name the wait-queue entry structure parameters
    and variables consistently and push through this naming into all
    the wait.h and wait.c code:
    
    	struct wait_queue_entry *wq_entry
    
    The 'wq_' prefix makes it easy to grep for, and we also use the
    opportunity to move away from the typedef to a plain 'struct' naming:
    in the kernel we typically reserve typedefs for cases where a
    C structure is really small and somewhat opaque - such as pte_t.
    
    wait-queue entries are neither small nor opaque, so use the more
    standard 'struct xxx_entry' list management code nomenclature instead.
    
    ( We don't touch external users, and we preserve the typedef as well
      for actual wait-queue users, to reduce unnecessary churn. )
    
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: linux-kernel@vger.kernel.org
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
    50816c48
wait.c 18.7 KB