From ad7660cc1ef13551e3d0a649aaba7c728b8c0ac0 Mon Sep 17 00:00:00 2001 From: Johannes Thumshirn Date: Thu, 17 Nov 2016 10:31:17 +0100 Subject: [PATCH] scsi: fc: implement kref backed reference counting 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 Reviewed-by: Hannes Reinecke Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi_transport_fc.c | 40 +++++++++----------------------- include/scsi/scsi_transport_fc.h | 4 +--- 2 files changed, 12 insertions(+), 32 deletions(-) diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c index 45954a6edd94..9009acc27aed 100644 --- a/drivers/scsi/scsi_transport_fc.c +++ b/drivers/scsi/scsi_transport_fc.c @@ -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; diff --git a/include/scsi/scsi_transport_fc.h b/include/scsi/scsi_transport_fc.h index 9f53fe3fa249..8ae5680f2216 100644 --- a/include/scsi/scsi_transport_fc.h +++ b/include/scsi/scsi_transport_fc.h @@ -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; -- 2.20.1