[PATCH 17/19] staging: lustre: remove l_wait_event from ptlrpc_set_wait

NeilBrown
2018-01-08T03:31:19Z

This is the last remaining use of l_wait_event().
It is the only use of LWI_TIMEOUT_INTR_ALL() which
has a meaning that timeouts can be interrupted.
Only interrupts by "fatal" signals are allowed, so
introduce l_wait_event_abortable_timeout() to
support this.

Signed-off-by: NeilBrown <neilb@suse.com>
---
drivers/staging/lustre/lustre/include/lustre_lib.h | 14 +++
drivers/staging/lustre/lustre/ptlrpc/client.c | 84 ++++++++------------
2 files changed, 49 insertions(+), 49 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/lustre_lib.h b/drivers/staging/lustre/lustre/include/lustre_lib.h
index 1939e959b92a..ccc1a329e42b 100644
--- a/drivers/staging/lustre/lustre/include/lustre_lib.h
+++ b/drivers/staging/lustre/lustre/include/lustre_lib.h
@@ -196,6 +196,10 @@ struct l_wait_info {
#define LUSTRE_FATAL_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | \
sigmask(SIGTERM) | sigmask(SIGQUIT) | \
sigmask(SIGALRM))
+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
@@ -347,6 +351,16 @@ do { \
__ret; \
})

+#define l_wait_event_abortable_timeout(wq, condition, timeout) \
+({ \
+ sigset_t __blocked; \
+ int __ret = 0; \
+ __blocked = cfs_block_sigsinv(LUSTRE_FATAL_SIGS); \
+ __ret = wait_event_interruptible_timeout(wq, condition, timeout);\
+ cfs_restore_sigs(__blocked); \
+ __ret; \
+})
+
#define l_wait_event_abortable_exclusive(wq, condition) \
({ \
sigset_t __blocked; \
diff --git a/drivers/staging/lustre/lustre/ptlrpc/client.c b/drivers/staging/lustre/lustre/ptlrpc/client.c
index ffdd3ffd62c6..3d689d6100bc 100644
--- a/drivers/staging/lustre/lustre/ptlrpc/client.c
+++ b/drivers/staging/lustre/lustre/ptlrpc/client.c
@@ -1774,7 +1774,7 @@ int ptlrpc_check_set(const struct lu_env *env, struct ptlrpc_request_set *set)
}

/*
- * ptlrpc_set_wait->l_wait_event sets lwi_allow_intr
+ * ptlrpc_set_wait allow signal to abort the timeout
* so it sets rq_intr regardless of individual rpc
* timeouts. The synchronous IO waiting path sets
* rq_intr irrespective of whether ptlrpcd
@@ -2122,8 +2122,7 @@ int ptlrpc_expire_one_request(struct ptlrpc_request *req, int async_unlink)

/**
* Time out all uncompleted requests in request set pointed by \a data
- * Callback used when waiting on sets with l_wait_event.
- * Always returns 1.
+ * Called when wait_event_idle_timeout times out.
*/
void ptlrpc_expired_set(struct ptlrpc_request_set *set)
{
@@ -2156,18 +2155,6 @@ void ptlrpc_expired_set(struct ptlrpc_request_set *set)
ptlrpc_expire_one_request(req, 1);
}
}
-static int ptlrpc_expired_set_void(void *data)
-{
- struct ptlrpc_request_set *set = data;
-
- ptlrpc_expired_set(set);
- /*
- * When waiting for a whole set, we always break out of the
- * sleep so we can recalculate the timeout, or enable interrupts
- * if everyone's timed out.
- */
- return 1;
-}

/**
* Sets rq_intr flag in \a req under spinlock.
@@ -2182,11 +2169,10 @@ EXPORT_SYMBOL(ptlrpc_mark_interrupted);

/**
* Interrupts (sets interrupted flag) all uncompleted requests in
- * a set \a data. Callback for l_wait_event for interruptible waits.
+ * a set \a data. Called when l_wait_event_abortable_timeout receives signal.
*/
-static void ptlrpc_interrupted_set(void *data)
+static void ptlrpc_interrupted_set(struct ptlrpc_request_set *set)
{
- struct ptlrpc_request_set *set = data;
struct list_head *tmp;

CDEBUG(D_RPCTRACE, "INTERRUPTED SET %p\n", set);
@@ -2256,7 +2242,6 @@ int ptlrpc_set_wait(struct ptlrpc_request_set *set)
{
struct list_head *tmp;
struct ptlrpc_request *req;
- struct l_wait_info lwi;
int rc, timeout;

if (set->set_producer)
@@ -2282,46 +2267,47 @@ int ptlrpc_set_wait(struct ptlrpc_request_set *set)
CDEBUG(D_RPCTRACE, "set %p going to sleep for %d seconds\n",
set, timeout);

- if (timeout == 0 && !signal_pending(current))
+ if (timeout == 0 && !signal_pending(current)) {
/*
* No requests are in-flight (ether timed out
* or delayed), so we can allow interrupts.
* We still want to block for a limited time,
* so we allow interrupts during the timeout.
*/
- lwi = LWI_TIMEOUT_INTR_ALL(HZ,
- ptlrpc_expired_set_void,
- ptlrpc_interrupted_set, set);
- else
+ rc = l_wait_event_abortable_timeout(set->set_waitq,
+ ptlrpc_check_set(NULL, set),
+ HZ);
+ if (rc == 0) {
+ rc = -ETIMEDOUT;
+ ptlrpc_expired_set(set);
+ } else if (rc < 0) {
+ rc = -EINTR;
+ ptlrpc_interrupted_set(set);
+ } else
+ rc = 0;
+ } else {
/*
* At least one request is in flight, so no
* interrupts are allowed. Wait until all
* complete, or an in-flight req times out.
*/
- lwi = LWI_TIMEOUT((timeout ? timeout : 1) * HZ,
- ptlrpc_expired_set_void, set);
-
- rc = l_wait_event(set->set_waitq, ptlrpc_check_set(NULL, set), &lwi);
-
- /*
- * LU-769 - if we ignored the signal because it was already
- * pending when we started, we need to handle it now or we risk
- * it being ignored forever
- */
- if (rc == -ETIMEDOUT && !lwi.lwi_allow_intr &&
- signal_pending(current)) {
- sigset_t blocked_sigs =
- cfs_block_sigsinv(LUSTRE_FATAL_SIGS);
-
- /*
- * In fact we only interrupt for the "fatal" signals
- * like SIGINT or SIGKILL. We still ignore less
- * important signals since ptlrpc set is not easily
- * reentrant from userspace again
- */
- if (signal_pending(current))
- ptlrpc_interrupted_set(set);
- cfs_restore_sigs(blocked_sigs);
+ rc = wait_event_idle_timeout(set->set_waitq,
+ ptlrpc_check_set(NULL, set),
+ (timeout ? timeout : 1) * HZ);
+ if (rc == 0) {
+ ptlrpc_expired_set(set);
+ rc = -ETIMEDOUT;
+ /*
+ * LU-769 - if we ignored the signal
+ * because it was already pending when
+ * we started, we need to handle it
+ * now or we risk it being ignored
+ * forever
+ */
+ if (l_fatal_signal_pending(current))
+ ptlrpc_interrupted_set(set);
+ } else
+ rc = 0;
}

LASSERT(rc == 0 || rc == -EINTR || rc == -ETIMEDOUT);
@@ -2528,7 +2514,7 @@ static int ptlrpc_unregister_reply(struct ptlrpc_request *request, int async)
return 0;

/*
- * We have to l_wait_event() whatever the result, to give liblustre
+ * We have to wait_event_idle_timeout() whatever the result, to give liblustre
* a chance to run reply_in_callback(), and to make sure we've
* unlinked before returning a req to the pool.
*/