From be34c62ddf39d1931780b07a6f4241393e4ba2ee Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 18 May 2015 13:22:19 +0200 Subject: [PATCH] scsi_transport_srp: Introduce srp_wait_for_queuecommand() Introduce the helper function srp_wait_for_queuecommand(). Move the definition of scsi_request_fn_active(). Add a comment above srp_wait_for_queuecommand() that support for scsi-mq needs to be added. This patch does not change any functionality. A second call to srp_wait_for_queuecommand() will be introduced in the next patch. Signed-off-by: Bart Van Assche Cc: James Bottomley Cc: Sagi Grimberg Cc: Sebastian Parschauer Cc: #v3.13 Signed-off-by: Doug Ledford --- drivers/scsi/scsi_transport_srp.c | 54 ++++++++++++++++++------------- 1 file changed, 31 insertions(+), 23 deletions(-) diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c index ae45bd99baed..e05cd7e2d6d3 100644 --- a/drivers/scsi/scsi_transport_srp.c +++ b/drivers/scsi/scsi_transport_srp.c @@ -396,6 +396,36 @@ 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); @@ -503,27 +533,6 @@ void srp_start_tl_fail_timers(struct srp_rport *rport) } EXPORT_SYMBOL(srp_start_tl_fail_timers); -/** - * 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. - */ -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; -} - /** * srp_reconnect_rport() - reconnect to an SRP target port * @rport: SRP target port. @@ -559,8 +568,7 @@ int srp_reconnect_rport(struct srp_rport *rport) if (res) goto out; scsi_target_block(&shost->shost_gendev); - while (scsi_request_fn_active(shost)) - msleep(20); + 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);