From e20fff8a1f4940f46be888bd175412c2e3e64e96 Mon Sep 17 00:00:00 2001 From: Martin Wilck Date: Wed, 14 Jun 2023 12:36:14 +0200 Subject: scsi: core: Don't wait for quiesce in scsi_device_block() scsi_device_block() is only called from scsi_target_block(), which calls it repeatedly for every child device. For targets with many devices, waiting for every queue to quiesce may cause a substantial delay (we measured more than 100s delay for blocking a FC rport with 2048 LUNs). Just call blk_mq_wait_quiesce_done() once from scsi_target_block() after stopping all queues. Signed-off-by: Martin Wilck Link: https://lore.kernel.org/r/20230614103616.31857-6-mwilck@suse.com Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi_lib.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'drivers/scsi') diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 4b46dcba7649..b98750028044 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2771,8 +2771,9 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); * @sdev: device to block * @data: dummy argument, ignored * - * Pause SCSI command processing on the specified device and wait until all - * ongoing scsi_queue_rq() calls have finished. May sleep. + * Pause SCSI command processing on the specified device. Callers must wait + * until all ongoing scsi_queue_rq() calls have finished after this function + * returns. * * Note: * This routine transitions the device to the SDEV_BLOCK state (which must be @@ -2786,17 +2787,15 @@ static void scsi_device_block(struct scsi_device *sdev, void *data) mutex_lock(&sdev->state_mutex); err = __scsi_internal_device_block_nowait(sdev); - if (err == 0) { + if (err == 0) /* * scsi_stop_queue() must be called with the state_mutex * held. Otherwise a simultaneous scsi_start_queue() call * might unquiesce the queue before we quiesce it. */ scsi_stop_queue(sdev); - mutex_unlock(&sdev->state_mutex); - blk_mq_wait_quiesce_done(sdev->request_queue->tag_set); - } else - mutex_unlock(&sdev->state_mutex); + + mutex_unlock(&sdev->state_mutex); WARN_ONCE(err, "__scsi_internal_device_block_nowait(%s) failed: err = %d\n", dev_name(&sdev->sdev_gendev), err); @@ -2894,11 +2893,15 @@ target_block(struct device *dev, void *data) void scsi_target_block(struct device *dev) { + struct Scsi_Host *shost = dev_to_shost(dev); + if (scsi_is_target_device(dev)) starget_for_each_device(to_scsi_target(dev), NULL, scsi_device_block); else device_for_each_child(dev, NULL, target_block); + + blk_mq_wait_quiesce_done(&shost->tag_set); } EXPORT_SYMBOL_GPL(scsi_target_block); -- cgit v1.2.3