Re: [PATCH 01/12] scsi_transport_srp: Introduce srp_wait_for_queuecommand()

Sagi Grimberg
2015-04-30T09:32:04Z

On 4/30/2015 11:56 AM, Bart Van Assche wrote:
> Introduce the helper function srp_wait_for_queuecommand().
> Move the definition of scsi_request_fn_active(). This patch
> does not change any functionality. A second call to
> scsi_wait_for_queuecommand() will be introduced in the next
> patch.
>
> Signed-off-by: Bart Van Assche <bart.vanassche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
> Cc: James Bottomley <JBottomley-O3H1v1f1dlM@public.gmane.org>
> Cc: Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Cc: Sebastian Parschauer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
> Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org> #v3.13
> ---
> drivers/scsi/scsi_transport_srp.c | 52 ++++++++++++++++++++++-----------------
> 1 file changed, 29 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
> index ae45bd9..6ce1c48 100644
> --- a/drivers/scsi/scsi_transport_srp.c
> +++ b/drivers/scsi/scsi_transport_srp.c
> @@ -396,6 +396,34 @@ 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.
> + */
> +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);
> @@ -504,27 +532,6 @@ 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 +566,7 @@ 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);
>

Looks good.

Reviewed-by: Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
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