Re: [PATCH 11/19] staging: lustre: remove back_to_sleep()

James Simmons
2018-01-17T15:33:07Z

> When 'back_to_sleep()' is passed as the 'timeout' function,
> the effect is to wait indefinitely for the event, polling
> once after the timeout.
> If LWI_ON_SIGNAL_NOOP is given, then after the timeout
> we allow fatal signals to interrupt the wait.
>
> Make this more obvious in both places "back_to_sleep()" is
> used but using two explicit sleeps.
>
> The code in ptlrpcd_add_req() looks odd - why not just have one
> wait_event_idle()? However I believe this is a faithful
> transformation of the existing code.

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

> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
> drivers/staging/lustre/lustre/include/lustre_lib.h | 4 ----
> drivers/staging/lustre/lustre/ptlrpc/import.c | 11 ++++++-----
> drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c | 9 +++++----
> 3 files changed, 11 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/staging/lustre/lustre/include/lustre_lib.h b/drivers/staging/lustre/lustre/include/lustre_lib.h
> index b2a64d0e682c..1939e959b92a 100644
> --- a/drivers/staging/lustre/lustre/include/lustre_lib.h
> +++ b/drivers/staging/lustre/lustre/include/lustre_lib.h
> @@ -140,10 +140,6 @@ void target_send_reply(struct ptlrpc_request *req, int rc, int fail_id);
> * 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))
>
> diff --git a/drivers/staging/lustre/lustre/ptlrpc/import.c b/drivers/staging/lustre/lustre/ptlrpc/import.c
> index 5d62c9de27eb..faf0f606f013 100644
> --- a/drivers/staging/lustre/lustre/ptlrpc/import.c
> +++ b/drivers/staging/lustre/lustre/ptlrpc/import.c
> @@ -1496,7 +1496,6 @@ int ptlrpc_disconnect_import(struct obd_import *imp, int noclose)
> }
>
> if (ptlrpc_import_in_recovery(imp)) {
> - struct l_wait_info lwi;
> long timeout;
>
> if (AT_OFF) {
> @@ -1510,10 +1509,12 @@ int ptlrpc_disconnect_import(struct obd_import *imp, int noclose)
> timeout = at_get(&imp->imp_at.iat_service_estimate[idx]) * HZ;
> }
>
> - lwi = LWI_TIMEOUT_INTR(cfs_timeout_cap(timeout),
> - back_to_sleep, LWI_ON_SIGNAL_NOOP, NULL);
> - rc = l_wait_event(imp->imp_recovery_waitq,
> - !ptlrpc_import_in_recovery(imp), &lwi);
> + if (wait_event_idle_timeout(imp->imp_recovery_waitq,
> + !ptlrpc_import_in_recovery(imp),
> + cfs_timeout_cap(timeout)) == 0)
> + l_wait_event_abortable(
> + imp->imp_recovery_waitq,
> + !ptlrpc_import_in_recovery(imp));
> }
>
> spin_lock(&imp->imp_lock);
> diff --git a/drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c b/drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c
> index dad2f9290f70..437b4b2a9072 100644
> --- a/drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c
> +++ b/drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c
> @@ -230,12 +230,13 @@ void ptlrpcd_add_req(struct ptlrpc_request *req)
>
> spin_lock(&req->rq_lock);
> if (req->rq_invalid_rqset) {
> - struct l_wait_info lwi = LWI_TIMEOUT(5 * HZ,
> - back_to_sleep, NULL);
> -
> req->rq_invalid_rqset = 0;
> spin_unlock(&req->rq_lock);
> - l_wait_event(req->rq_set_waitq, !req->rq_set, &lwi);
> + if (wait_event_idle_timeout(req->rq_set_waitq,
> + !req->rq_set,
> + 5 * HZ) == 0)
> + wait_event_idle(req->rq_set_waitq,
> + !req->rq_set);
> } else if (req->rq_set) {
> /* If we have a valid "rq_set", just reuse it to avoid double
> * linked.
>
>
>