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scsi: fc: implement kref backed reference counting

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Implement kref backed reference counting instead of rolling our own. This
elimnates the need of the following fields in 'struct fc_bsg_job':
* ref_cnt
* state_flags
* job_lock
bringing us close to unification of 'struct fc_bsg_job' and 'struct bsg_job'.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Johannes Thumshirn 2016-11-17 10:31:17 +01:00 committed by Martin K. Petersen
parent 7ac65007c2
commit ad7660cc1e
2 changed files with 12 additions and 32 deletions
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40
drivers/scsi/scsi_transport_fc.c
View file

@ -3560,16 +3560,12 @@ fc_vport_sched_delete(struct work_struct *work)
* @job: fc_bsg_job that is to be torn down
*/
static void
fc_destroy_bsgjob(struct fc_bsg_job *job)
fc_destroy_bsgjob(struct kref *kref)
{
unsigned long flags;
struct fc_bsg_job *job = container_of(kref, struct fc_bsg_job, kref);
struct request *rq = job->req;
spin_lock_irqsave(&job->job_lock, flags);
if (job->ref_cnt) {
spin_unlock_irqrestore(&job->job_lock, flags);
return;
}
spin_unlock_irqrestore(&job->job_lock, flags);
blk_end_request_all(rq, rq->errors);
put_device(job->dev); /* release reference for the request */
@ -3620,15 +3616,8 @@ EXPORT_SYMBOL_GPL(fc_bsg_jobdone);
static void fc_bsg_softirq_done(struct request *rq)
{
struct fc_bsg_job *job = rq->special;
unsigned long flags;
spin_lock_irqsave(&job->job_lock, flags);
job->state_flags |= FC_RQST_STATE_DONE;
job->ref_cnt--;
spin_unlock_irqrestore(&job->job_lock, flags);
blk_end_request_all(rq, rq->errors);
fc_destroy_bsgjob(job);
kref_put(&job->kref, fc_destroy_bsgjob);
}
/**
@ -3642,24 +3631,18 @@ fc_bsg_job_timeout(struct request *req)
struct Scsi_Host *shost = fc_bsg_to_shost(job);
struct fc_rport *rport = fc_bsg_to_rport(job);
struct fc_internal *i = to_fc_internal(shost->transportt);
unsigned long flags;
int err = 0, done = 0;
int err = 0, inflight = 0;
if (rport && rport->port_state == FC_PORTSTATE_BLOCKED)
return BLK_EH_RESET_TIMER;
spin_lock_irqsave(&job->job_lock, flags);
if (job->state_flags & FC_RQST_STATE_DONE)
done = 1;
else
job->ref_cnt++;
spin_unlock_irqrestore(&job->job_lock, flags);
inflight = kref_get_unless_zero(&job->kref);
if (!done && i->f->bsg_timeout) {
if (inflight && i->f->bsg_timeout) {
/* call LLDD to abort the i/o as it has timed out */
err = i->f->bsg_timeout(job);
if (err == -EAGAIN) {
job->ref_cnt--;
kref_put(&job->kref, fc_destroy_bsgjob);
return BLK_EH_RESET_TIMER;
} else if (err)
printk(KERN_ERR "ERROR: FC BSG request timeout - LLD "
@ -3667,7 +3650,7 @@ fc_bsg_job_timeout(struct request *req)
}
/* the blk_end_sync_io() doesn't check the error */
if (done)
if (!inflight)
return BLK_EH_NOT_HANDLED;
else
return BLK_EH_HANDLED;
@ -3728,7 +3711,6 @@ fc_req_to_bsgjob(struct Scsi_Host *shost, struct fc_rport *rport,
job->req = req;
if (i->f->dd_bsg_size)
job->dd_data = (void *)&job[1];
spin_lock_init(&job->job_lock);
job->request = (struct fc_bsg_request *)req->cmd;
job->request_len = req->cmd_len;
job->reply = req->sense;
@ -3750,7 +3732,7 @@ fc_req_to_bsgjob(struct Scsi_Host *shost, struct fc_rport *rport,
job->dev = &shost->shost_gendev;
get_device(job->dev); /* take a reference for the request */
job->ref_cnt = 1;
kref_init(&job->kref);
return 0;

4
include/scsi/scsi_transport_fc.h
View file

@ -634,9 +634,7 @@ struct fc_bsg_job {
struct fc_rport *rport;
struct device *dev;
struct request *req;
spinlock_t job_lock;
unsigned int state_flags;
unsigned int ref_cnt;
struct kref kref;
struct fc_bsg_request *request;
struct fc_bsg_reply *reply;