On Wed, Aug 03, 2016 at 03:13:01PM +0200, Hannes Reinecke wrote:
> The kref handling in fc_rport is a mess. This patch updates
> the kref handling according to the following rules:
>
> - Take a reference whenever scheduling a workqueue
> - Take a reference whenever an ELS command is send
> - Drop the reference at the end of the workqueue function
> - Drop the reference at the end of handling ELS replies
> - Take a reference when allocating an rport
> - Drop the reference when removing an rport
>
> Signed-off-by: Hannes Reinecke <hare@xxxxxxxx>
> ---
> drivers/scsi/libfc/fc_rport.c | 134 ++++++++++++++++++++++++++++++++----------
> 1 file changed, 103 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c
> index 93f5961..6a98bb8 100644
> --- a/drivers/scsi/libfc/fc_rport.c
> +++ b/drivers/scsi/libfc/fc_rport.c
> @@ -44,6 +44,17 @@
> * path this potential over-use of the mutex is acceptable.
> */
>
> +/*
> + * RPORT REFERENCE COUNTING
> + *
> + * A rport reference should be taken when:
> + * - a workqueue item is scheduled
> + * - an ELS request is send
> + * The reference should be dropped when:
> + * - the workqueue function has finished
> + * - the ELS response is handled
> + */
Please sync with the rules in the commit message.
> +
> #include <linux/kernel.h>
> #include <linux/spinlock.h>
> #include <linux/interrupt.h>
> @@ -242,6 +253,8 @@ static void fc_rport_state_enter(struct fc_rport_priv *rdata,
> /**
> * fc_rport_work() - Handler for remote port events in the rport_event_queue
> * @work: Handle to the remote port being dequeued
> + *
> + * Reference counting: drops kref on return
> */
> static void fc_rport_work(struct work_struct *work)
> {
> @@ -272,8 +285,10 @@ static void fc_rport_work(struct work_struct *work)
> kref_get(&rdata->kref);
> mutex_unlock(&rdata->rp_mutex);
>
> - if (!rport)
> + if (!rport) {
> + FC_RPORT_DBG(rdata, "No rport!\n");
If you're re-sending the series, this and the other added debug statements
might be better suited in '[PATCH 02/22] libfc: additional debugging messages'.
Otherwise
Acked-by: Johannes Thumshirn <jth@xxxxxxxxxx>
--
Johannes Thumshirn Storage
jthumshirn@xxxxxxx +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
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