struct ptlrpc_request;
struct obd_export;
struct lu_target;
-struct l_wait_info;
#include <lustre_ha.h>
#include <lustre_net.h>
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)
- *
- * OBD_FREE_PTR(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.
- *
- */
-static inline int back_to_sleep(void *arg)
-{
- return 0;
-}
-
-#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)
-
-/**
- * wait_queue_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 != NULL && (__timeout == 0 || __allow_intr)) \
- __blocked = cfs_block_sigsinv(LUSTRE_FATAL_SIGS); \
- else \
- __blocked = cfs_block_sigsinv(0); \
- \
- for (;;) { \
- set_current_state(TASK_INTERRUPTIBLE); \
- \
- /* To guarantee that the condition check will be done */ \
- /* after setting the thread state as TASK_INTERRUPTIBLE. */ \
- /* Otherwise, out-of-order execution may cause some race. */ \
- /* Consider the following real execution order: */ \
- \
- /* 1. Thread1 checks condition on CPU1, gets false. */ \
- /* 2. Thread2 sets condition on CPU2. */ \
- /* 3. Thread2 calls wake_up() on CPU2 to wake the threads */ \
- /* with state TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE. */ \
- /* But the Thread1's state is TASK_RUNNING at that time. */ \
- /* 4. Thread1 sets its state as TASK_INTERRUPTIBLE on CPU1, */ \
- /* then schedule. */ \
- \
- /* If the '__timeout' variable is zero, the Thread1 will */ \
- /* have no chance to check the condition again. */ \
- \
- /* Generally, the interval between out-of-ordered step1 and */ \
- /* step4 is very tiny, as to above step2 and step3 cannot */ \
- /* happen. On some degree, it can explain why we seldom hit */ \
- /* related trouble. But such race really exists, especially */ \
- /* consider that the step1 and step4 can be interruptible. */ \
- /* So add barrier to avoid Thread1 out-of-order execution. */ \
- smp_mb(); \
- \
- if (condition) \
- break; \
- \
- if (__timeout == 0) { \
- schedule(); \
- } else { \
- long interval = info->lwi_interval ? \
- min_t(long, info->lwi_interval,\
- __timeout) : __timeout; \
- long remaining = schedule_timeout(interval); \
- \
- __timeout -= interval - remaining; \
- if (__timeout == 0) { \
- if (info->lwi_on_timeout == NULL || \
- info->lwi_on_timeout(info->lwi_cb_data)) { \
- ret = -ETIMEDOUT; \
- break; \
- } \
- /* Take signals after the timeout expires. */ \
- if (info->lwi_on_signal != NULL) \
- (void)cfs_block_sigsinv(LUSTRE_FATAL_SIGS);\
- } \
- } \
- \
- if (condition) \
- break; \
- if (signal_pending(current)) { \
- unsigned long flags; \
- \
- if (info->lwi_on_signal != NULL && \
- (__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. */ \
- spin_lock_irqsave(¤t->sighand->siglock, flags); \
- clear_tsk_thread_flag(current, TIF_SIGPENDING); \
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);\
- } \
- } \
- \
- cfs_restore_sigs(__blocked); \
- \
- set_current_state(TASK_RUNNING); \
- 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; \
-})
-
-#define l_wait_condition(wq, condition) \
-({ \
- struct l_wait_info lwi = { 0 }; \
- l_wait_event(wq, condition, &lwi); \
-})
-
-#define l_wait_condition_exclusive(wq, condition) \
-({ \
- struct l_wait_info lwi = { 0 }; \
- l_wait_event_exclusive(wq, condition, &lwi); \
-})
-
-#define l_wait_condition_exclusive_head(wq, condition) \
-({ \
- struct l_wait_info lwi = { 0 }; \
- l_wait_event_exclusive_head(wq, condition, &lwi); \
-})
-
/** @} lib */
#endif /* _LUSTRE_LIB_H */
git://git.whamcloud.com / fs / lustre-release.git / commitdiff