| Message ID | 489a9322eed1f95f8770752cc715084f1fa961d3.1667314759.git.nickyc975@zju.edu.cn (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | some random cleanups for blk-mq.c | expand |
On Tue, Nov 01, 2022 at 11:11:34PM +0800, Jinlong Chen wrote: > blk_mq_quiesce_queue_nowait() is now reasonably used by scsi_host_block() > to avoid calling synchronize_rcu() for each LUN. We should not consider to > remove it. I strongly disagree about this being a reasonable use. What SCSI did there is a horrible hack that should have never been merged. The right thing to do is the per-tag_set quiesce that we've been working on.
> On Tue, Nov 01, 2022 at 11:11:34PM +0800, Jinlong Chen wrote: > > blk_mq_quiesce_queue_nowait() is now reasonably used by scsi_host_block() > > to avoid calling synchronize_rcu() for each LUN. We should not consider to > > remove it. > > I strongly disagree about this being a reasonable use. What SCSI did > there is a horrible hack that should have never been merged. The > right thing to do is the per-tag_set quiesce that we've been working > on. Ok, I guess I need to read the per-tag_set quiesce patch series. Thanks! Jinlong Chen
diff --git a/block/blk-mq.c b/block/blk-mq.c index 623e8a506539..7ceceea91b3b 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -237,9 +237,12 @@ void blk_mq_unfreeze_queue(struct request_queue *q) } EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); -/* - * FIXME: replace the scsi_internal_device_*block_nowait() calls in the - * mpt3sas driver such that this function can be removed. +/** + * blk_mq_quiesce_queue_nowait() - start the quiesce of the queue + * @q: request queue. + * + * Note: synchronize_rcu() or synchronize_srcu(q->srcu) needs to + * be called to ensure the quiesce is done. */ void blk_mq_quiesce_queue_nowait(struct request_queue *q) {
blk_mq_quiesce_queue_nowait() is now reasonably used by scsi_host_block() to avoid calling synchronize_rcu() for each LUN. We should not consider to remove it. See commit f983622ae60516d634008c7b1ff9ffff4f7bb8ae ("scsi: core: Avoid calling synchronize_rcu() for each device in scsi_host_block()") Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn> --- block/blk-mq.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)