From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: [PATCH v5 11/14] SRP transport: Move queuecommand() wait code to SCSI core To: Jens Axboe References: <7460e8b2-2cfd-c0d5-7ae7-7f662d89dad3@sandisk.com> CC: Christoph Hellwig , James Bottomley , "Martin K. Petersen" , Mike Snitzer , Doug Ledford , Keith Busch , Ming Lei , "Konrad Rzeszutek Wilk" , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Laurence Oberman , "linux-block@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" From: Bart Van Assche Message-ID: Date: Fri, 28 Oct 2016 17:22:37 -0700 MIME-Version: 1.0 In-Reply-To: <7460e8b2-2cfd-c0d5-7ae7-7f662d89dad3@sandisk.com> Content-Type: text/plain; charset="utf-8" Sender: linux-scsi-owner@vger.kernel.org List-ID: Additionally, rename srp_wait_for_queuecommand() into scsi_wait_for_queuecommand() and add a comment about the queuecommand() call from scsi_send_eh_cmnd(). Signed-off-by: Bart Van Assche Cc: James Bottomley Cc: Martin K. Petersen Cc: Christoph Hellwig Cc: Sagi Grimberg Cc: Doug Ledford --- drivers/scsi/scsi_lib.c | 38 ++++++++++++++++++++++++++++++++++++ drivers/scsi/scsi_transport_srp.c | 41 ++++++--------------------------------- 2 files changed, 44 insertions(+), 35 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index b4f682c..3ab9c87 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2721,6 +2721,39 @@ void sdev_evt_send_simple(struct scsi_device *sdev, EXPORT_SYMBOL_GPL(sdev_evt_send_simple); /** + * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn() + * @sdev: SCSI device to count the number of scsi_request_fn() callers for. + */ +static int scsi_request_fn_active(struct scsi_device *sdev) +{ + struct request_queue *q = sdev->request_queue; + int request_fn_active; + + WARN_ON_ONCE(sdev->host->use_blk_mq); + + spin_lock_irq(q->queue_lock); + request_fn_active = q->request_fn_active; + spin_unlock_irq(q->queue_lock); + + return request_fn_active; +} + +/** + * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls + * @shost: SCSI host pointer. + * + * Wait until the ongoing shost->hostt->queuecommand() calls that are + * invoked from scsi_request_fn() have finished. + */ +static void scsi_wait_for_queuecommand(struct scsi_device *sdev) +{ + WARN_ON_ONCE(sdev->host->use_blk_mq); + + while (scsi_request_fn_active(sdev)) + msleep(20); +} + +/** * scsi_device_quiesce - Block user issued commands. * @sdev: scsi device to quiesce. * @@ -2814,6 +2847,10 @@ EXPORT_SYMBOL(scsi_target_resume); * (which must be a legal transition). When the device is in this * state, all commands are deferred until the scsi lld reenables * the device with scsi_device_unblock or device_block_tmo fires. + * + * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after + * scsi_internal_device_block() has blocked a SCSI device and also + * remove the rport mutex lock and unlock calls from srp_queuecommand(). */ int scsi_internal_device_block(struct scsi_device *sdev) @@ -2841,6 +2878,7 @@ scsi_internal_device_block(struct scsi_device *sdev) spin_lock_irqsave(q->queue_lock, flags); blk_stop_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); + scsi_wait_for_queuecommand(sdev); } return 0; diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c index e3cd3ec..b48328a 100644 --- a/drivers/scsi/scsi_transport_srp.c +++ b/drivers/scsi/scsi_transport_srp.c @@ -24,7 +24,6 @@ #include #include #include -#include #include #include @@ -402,36 +401,6 @@ static void srp_reconnect_work(struct work_struct *work) } } -/** - * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn() - * @shost: SCSI host for which to count the number of scsi_request_fn() callers. - * - * To do: add support for scsi-mq in this function. - */ -static int scsi_request_fn_active(struct Scsi_Host *shost) -{ - struct scsi_device *sdev; - struct request_queue *q; - int request_fn_active = 0; - - shost_for_each_device(sdev, shost) { - q = sdev->request_queue; - - spin_lock_irq(q->queue_lock); - request_fn_active += q->request_fn_active; - spin_unlock_irq(q->queue_lock); - } - - return request_fn_active; -} - -/* Wait until ongoing shost->hostt->queuecommand() calls have finished. */ -static void srp_wait_for_queuecommand(struct Scsi_Host *shost) -{ - while (scsi_request_fn_active(shost)) - msleep(20); -} - static void __rport_fail_io_fast(struct srp_rport *rport) { struct Scsi_Host *shost = rport_to_shost(rport); @@ -441,14 +410,17 @@ static void __rport_fail_io_fast(struct srp_rport *rport) if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST)) return; + /* + * Call scsi_target_block() to wait for ongoing shost->queuecommand() + * calls before invoking i->f->terminate_rport_io(). + */ + scsi_target_block(rport->dev.parent); scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE); /* Involve the LLD if possible to terminate all I/O on the rport. */ i = to_srp_internal(shost->transportt); - if (i->f->terminate_rport_io) { - srp_wait_for_queuecommand(shost); + if (i->f->terminate_rport_io) i->f->terminate_rport_io(rport); - } } /** @@ -576,7 +548,6 @@ int srp_reconnect_rport(struct srp_rport *rport) if (res) goto out; scsi_target_block(&shost->shost_gendev); - srp_wait_for_queuecommand(shost); res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV; pr_debug("%s (state %d): transport.reconnect() returned %d\n", dev_name(&shost->shost_gendev), rport->state, res); -- 2.10.1