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

James Simmons
2018-01-17T15:36:49Z

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

Reviewed-by: James Simmons <jsimmons@infradead.org>

> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
> 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 */
>
>
>
>
>