Re: [PATCH 19/19] staging: lustre: remove l_wait_event() and related code

[James Simmons]

> These macros are no longer used, so they can
> be removed.

Reviewed-by: James Simmons <jsimmons@xxxxxxxxxxxxx>
 
> Signed-off-by: NeilBrown <neilb@xxxxxxxx>
> ---
>  drivers/staging/lustre/lustre/include/lustre_lib.h |  249 --------------------
>  1 file changed, 249 deletions(-)
> 
> diff --git a/drivers/staging/lustre/lustre/include/lustre_lib.h b/drivers/staging/lustre/lustre/include/lustre_lib.h
> index ccc1a329e42b..1efd86f18c1f 100644
> --- a/drivers/staging/lustre/lustre/include/lustre_lib.h
> +++ b/drivers/staging/lustre/lustre/include/lustre_lib.h
> @@ -76,123 +76,6 @@ int do_set_info_async(struct obd_import *imp,
>  
>  void target_send_reply(struct ptlrpc_request *req, int rc, int fail_id);
>  
> -/*
> - * l_wait_event is a flexible sleeping function, permitting simple caller
> - * configuration of interrupt and timeout sensitivity along with actions to
> - * be performed in the event of either exception.
> - *
> - * The first form of usage looks like this:
> - *
> - * struct l_wait_info lwi = LWI_TIMEOUT_INTR(timeout, timeout_handler,
> - *					   intr_handler, callback_data);
> - * rc = l_wait_event(waitq, condition, &lwi);
> - *
> - * l_wait_event() makes the current process wait on 'waitq' until 'condition'
> - * is TRUE or a "killable" signal (SIGTERM, SIKGILL, SIGINT) is pending.  It
> - * returns 0 to signify 'condition' is TRUE, but if a signal wakes it before
> - * 'condition' becomes true, it optionally calls the specified 'intr_handler'
> - * if not NULL, and returns -EINTR.
> - *
> - * If a non-zero timeout is specified, signals are ignored until the timeout
> - * has expired.  At this time, if 'timeout_handler' is not NULL it is called.
> - * If it returns FALSE l_wait_event() continues to wait as described above with
> - * signals enabled.  Otherwise it returns -ETIMEDOUT.
> - *
> - * LWI_INTR(intr_handler, callback_data) is shorthand for
> - * LWI_TIMEOUT_INTR(0, NULL, intr_handler, callback_data)
> - *
> - * The second form of usage looks like this:
> - *
> - * struct l_wait_info lwi = LWI_TIMEOUT(timeout, timeout_handler);
> - * rc = l_wait_event(waitq, condition, &lwi);
> - *
> - * This form is the same as the first except that it COMPLETELY IGNORES
> - * SIGNALS.  The caller must therefore beware that if 'timeout' is zero, or if
> - * 'timeout_handler' is not NULL and returns FALSE, then the ONLY thing that
> - * can unblock the current process is 'condition' becoming TRUE.
> - *
> - * Another form of usage is:
> - * struct l_wait_info lwi = LWI_TIMEOUT_INTERVAL(timeout, interval,
> - *					       timeout_handler);
> - * rc = l_wait_event(waitq, condition, &lwi);
> - * This is the same as previous case, but condition is checked once every
> - * 'interval' jiffies (if non-zero).
> - *
> - * Subtle synchronization point: this macro does *not* necessary takes
> - * wait-queue spin-lock before returning, and, hence, following idiom is safe
> - * ONLY when caller provides some external locking:
> - *
> - *	     Thread1			    Thread2
> - *
> - *   l_wait_event(&obj->wq, ....);				       (1)
> - *
> - *				    wake_up(&obj->wq):		 (2)
> - *					 spin_lock(&q->lock);	  (2.1)
> - *					 __wake_up_common(q, ...);     (2.2)
> - *					 spin_unlock(&q->lock, flags); (2.3)
> - *
> - *   kfree(obj);						  (3)
> - *
> - * As l_wait_event() may "short-cut" execution and return without taking
> - * wait-queue spin-lock, some additional synchronization is necessary to
> - * guarantee that step (3) can begin only after (2.3) finishes.
> - *
> - * XXX nikita: some ptlrpc daemon threads have races of that sort.
> - *
> - */
> -
> -#define LWI_ON_SIGNAL_NOOP ((void (*)(void *))(-1))
> -
> -struct l_wait_info {
> -	long lwi_timeout;
> -	long lwi_interval;
> -	int	    lwi_allow_intr;
> -	int  (*lwi_on_timeout)(void *);
> -	void (*lwi_on_signal)(void *);
> -	void  *lwi_cb_data;
> -};
> -
> -/* NB: LWI_TIMEOUT ignores signals completely */
> -#define LWI_TIMEOUT(time, cb, data)	     \
> -((struct l_wait_info) {			 \
> -	.lwi_timeout    = time,		 \
> -	.lwi_on_timeout = cb,		   \
> -	.lwi_cb_data    = data,		 \
> -	.lwi_interval   = 0,		    \
> -	.lwi_allow_intr = 0		     \
> -})
> -
> -#define LWI_TIMEOUT_INTERVAL(time, interval, cb, data)  \
> -((struct l_wait_info) {				 \
> -	.lwi_timeout    = time,			 \
> -	.lwi_on_timeout = cb,			   \
> -	.lwi_cb_data    = data,			 \
> -	.lwi_interval   = interval,		     \
> -	.lwi_allow_intr = 0			     \
> -})
> -
> -#define LWI_TIMEOUT_INTR(time, time_cb, sig_cb, data)   \
> -((struct l_wait_info) {				 \
> -	.lwi_timeout    = time,			 \
> -	.lwi_on_timeout = time_cb,		      \
> -	.lwi_on_signal  = sig_cb,		       \
> -	.lwi_cb_data    = data,			 \
> -	.lwi_interval   = 0,			    \
> -	.lwi_allow_intr = 0			     \
> -})
> -
> -#define LWI_TIMEOUT_INTR_ALL(time, time_cb, sig_cb, data)       \
> -((struct l_wait_info) {					 \
> -	.lwi_timeout    = time,				 \
> -	.lwi_on_timeout = time_cb,			      \
> -	.lwi_on_signal  = sig_cb,			       \
> -	.lwi_cb_data    = data,				 \
> -	.lwi_interval   = 0,				    \
> -	.lwi_allow_intr = 1				     \
> -})
> -
> -#define LWI_INTR(cb, data)  LWI_TIMEOUT_INTR(0, NULL, cb, data)
> -
>  #define LUSTRE_FATAL_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) |		\
>  			   sigmask(SIGTERM) | sigmask(SIGQUIT) |	\
>  			   sigmask(SIGALRM))
> @@ -201,138 +84,6 @@ static inline int l_fatal_signal_pending(struct task_struct *p)
>  	return signal_pending(p) && sigtestsetmask(&p->pending.signal, LUSTRE_FATAL_SIGS);
>  }
>  
> -/**
> - * wait_queue_entry_t of Linux (version < 2.6.34) is a FIFO list for exclusively
> - * waiting threads, which is not always desirable because all threads will
> - * be waken up again and again, even user only needs a few of them to be
> - * active most time. This is not good for performance because cache can
> - * be polluted by different threads.
> - *
> - * LIFO list can resolve this problem because we always wakeup the most
> - * recent active thread by default.
> - *
> - * NB: please don't call non-exclusive & exclusive wait on the same
> - * waitq if add_wait_queue_exclusive_head is used.
> - */
> -#define add_wait_queue_exclusive_head(waitq, link)		\
> -{								\
> -	unsigned long flags;					\
> -								\
> -	spin_lock_irqsave(&((waitq)->lock), flags);		\
> -	__add_wait_queue_exclusive(waitq, link);		\
> -	spin_unlock_irqrestore(&((waitq)->lock), flags);	\
> -}
> -
> -/*
> - * wait for @condition to become true, but no longer than timeout, specified
> - * by @info.
> - */
> -#define __l_wait_event(wq, condition, info, ret, l_add_wait)		   \
> -do {									   \
> -	wait_queue_entry_t __wait;						 \
> -	long __timeout = info->lwi_timeout;			  \
> -	sigset_t   __blocked;					      \
> -	int   __allow_intr = info->lwi_allow_intr;			     \
> -									       \
> -	ret = 0;							       \
> -	if (condition)							 \
> -		break;							 \
> -									       \
> -	init_waitqueue_entry(&__wait, current);					    \
> -	l_add_wait(&wq, &__wait);					      \
> -									       \
> -	/* Block all signals (just the non-fatal ones if no timeout). */       \
> -	if (info->lwi_on_signal && (__timeout == 0 || __allow_intr))   \
> -		__blocked = cfs_block_sigsinv(LUSTRE_FATAL_SIGS);	      \
> -	else								   \
> -		__blocked = cfs_block_sigsinv(0);			      \
> -									       \
> -	for (;;) {							     \
> -		if (condition)						 \
> -			break;						 \
> -									       \
> -		set_current_state(TASK_INTERRUPTIBLE);			       \
> -									       \
> -		if (__timeout == 0) {					  \
> -			schedule();					       \
> -		} else {						       \
> -			long interval = info->lwi_interval ?	  \
> -					     min_t(long,	     \
> -						 info->lwi_interval, __timeout) : \
> -					     __timeout;			\
> -			long remaining = schedule_timeout(interval);\
> -			__timeout = cfs_time_sub(__timeout,		    \
> -					    cfs_time_sub(interval, remaining));\
> -			if (__timeout == 0) {				  \
> -				if (!info->lwi_on_timeout ||		      \
> -				    info->lwi_on_timeout(info->lwi_cb_data)) { \
> -					ret = -ETIMEDOUT;		      \
> -					break;				 \
> -				}					      \
> -				/* Take signals after the timeout expires. */  \
> -				if (info->lwi_on_signal)		       \
> -				    (void)cfs_block_sigsinv(LUSTRE_FATAL_SIGS);\
> -			}						      \
> -		}							      \
> -									       \
> -		set_current_state(TASK_RUNNING);			       \
> -									       \
> -		if (condition)						 \
> -			break;						 \
> -		if (signal_pending(current)) {				    \
> -			if (info->lwi_on_signal &&		     \
> -			    (__timeout == 0 || __allow_intr)) {		\
> -				if (info->lwi_on_signal != LWI_ON_SIGNAL_NOOP) \
> -					info->lwi_on_signal(info->lwi_cb_data);\
> -				ret = -EINTR;				  \
> -				break;					 \
> -			}						      \
> -			/* We have to do this here because some signals */     \
> -			/* are not blockable - ie from strace(1).       */     \
> -			/* In these cases we want to schedule_timeout() */     \
> -			/* again, because we don't want that to return  */     \
> -			/* -EINTR when the RPC actually succeeded.      */     \
> -			/* the recalc_sigpending() below will deliver the */     \
> -			/* signal properly.			     */     \
> -			cfs_clear_sigpending();				\
> -		}							      \
> -	}								      \
> -									       \
> -	cfs_restore_sigs(__blocked);					   \
> -									       \
> -	remove_wait_queue(&wq, &__wait);					   \
> -} while (0)
> -
> -#define l_wait_event(wq, condition, info)		       \
> -({							      \
> -	int		 __ret;			      \
> -	struct l_wait_info *__info = (info);		    \
> -								\
> -	__l_wait_event(wq, condition, __info,		   \
> -		       __ret, add_wait_queue);		   \
> -	__ret;						  \
> -})
> -
> -#define l_wait_event_exclusive(wq, condition, info)	     \
> -({							      \
> -	int		 __ret;			      \
> -	struct l_wait_info *__info = (info);		    \
> -								\
> -	__l_wait_event(wq, condition, __info,		   \
> -		       __ret, add_wait_queue_exclusive);	 \
> -	__ret;						  \
> -})
> -
> -#define l_wait_event_exclusive_head(wq, condition, info)	\
> -({							      \
> -	int		 __ret;			      \
> -	struct l_wait_info *__info = (info);		    \
> -								\
> -	__l_wait_event(wq, condition, __info,		   \
> -		       __ret, add_wait_queue_exclusive_head);    \
> -	__ret;						  \
> -})
> -
>  /** @} lib */
>  
>  
> 
> 
>