Re: [PATCHv2 1/5] block: support polling through blk_execute_rq
From: Christoph Hellwig <hch@lst.de>
Date: 2021-04-26 14:35:48
Also in:
linux-nvme
On Fri, Apr 23, 2021 at 03:05:54PM -0700, Keith Busch wrote:
quoted hunk ↗ jump to hunk
Poll for completions if the request's hctx is a polling type. Signed-off-by: Keith Busch <kbusch@kernel.org> --- block/blk-exec.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)diff --git a/block/blk-exec.c b/block/blk-exec.c index beae70a0e5e5..b960ad187ba5 100644 --- a/block/blk-exec.c +++ b/block/blk-exec.c@@ -63,6 +63,11 @@ void blk_execute_rq_nowait(struct gendisk *bd_disk, struct request *rq, } EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); +static bool blk_rq_is_poll(struct request *rq) +{ + return rq->mq_hctx && rq->mq_hctx->type == HCTX_TYPE_POLL; +} + /** * blk_execute_rq - insert a request into queue for execution * @bd_disk: matching gendisk@@ -83,7 +88,12 @@ void blk_execute_rq(struct gendisk *bd_disk, struct request *rq, int at_head) /* Prevent hang_check timer from firing at us during very long I/O */ hang_check = sysctl_hung_task_timeout_secs; - if (hang_check) + if (blk_rq_is_poll(rq)) { + do { + blk_poll(rq->q, request_to_qc_t(rq->mq_hctx, rq), true); + cond_resched(); + } while (!completion_done(&wait));
I think it would be nice to split this into a little helper.
+ } else if (hang_check) while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
And while we're at it, it would be nice to split this out as well and document this mess..