Re: [PATCH 12/19] staging: lustre: make polling loop in ptlrpc_unregister_bulk more obvious

James Simmons
2018-01-17T15:33:32Z

> This use of l_wait_event() is a polling loop that re-checks
> every second. Make this more obvious with a while loop
> and wait_event_idle_timeout().

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

> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
> drivers/staging/lustre/lustre/ptlrpc/niobuf.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/staging/lustre/lustre/ptlrpc/niobuf.c b/drivers/staging/lustre/lustre/ptlrpc/niobuf.c
> index 0c2ded721c49..86883abaad2c 100644
> --- a/drivers/staging/lustre/lustre/ptlrpc/niobuf.c
> +++ b/drivers/staging/lustre/lustre/ptlrpc/niobuf.c
> @@ -229,7 +229,6 @@ int ptlrpc_unregister_bulk(struct ptlrpc_request *req, int async)
> {
> struct ptlrpc_bulk_desc *desc = req->rq_bulk;
> wait_queue_head_t *wq;
> - struct l_wait_info lwi;
> int rc;
>
> LASSERT(!in_interrupt()); /* might sleep */
> @@ -246,7 +245,7 @@ int ptlrpc_unregister_bulk(struct ptlrpc_request *req, int async)
>
> /* the unlink ensures the callback happens ASAP and is the last
> * one. If it fails, it must be because completion just happened,
> - * but we must still l_wait_event() in this case to give liblustre
> + * but we must still wait_event() in this case to give liblustre
> * a chance to run client_bulk_callback()
> */
> mdunlink_iterate_helper(desc->bd_mds, desc->bd_md_max_brw);
> @@ -270,15 +269,17 @@ int ptlrpc_unregister_bulk(struct ptlrpc_request *req, int async)
> /* Network access will complete in finite time but the HUGE
> * timeout lets us CWARN for visibility of sluggish LNDs
> */
> - lwi = LWI_TIMEOUT_INTERVAL(LONG_UNLINK * HZ,
> - HZ, NULL, NULL);
> - rc = l_wait_event(*wq, !ptlrpc_client_bulk_active(req), &lwi);
> - if (rc == 0) {
> + int cnt = 0;
> + while (cnt < LONG_UNLINK &&
> + (rc = wait_event_idle_timeout(*wq,
> + !ptlrpc_client_bulk_active(req),
> + HZ)) == 0)
> + cnt += 1;
> + if (rc > 0) {
> ptlrpc_rqphase_move(req, req->rq_next_phase);
> return 1;
> }
>
> - LASSERT(rc == -ETIMEDOUT);
> DEBUG_REQ(D_WARNING, req, "Unexpectedly long timeout: desc %p",
> desc);
> }
>
>
>