[PATCH v2 15/16] scsi: fc: move FC transport's bsg code to bsg-lib

From: Johannes Thumshirn
Date: Wed Oct 12 2016 - 09:08:49 EST


Now that all conversions are done, move the FibreChannel bsg code over to the
bsg library. Note that CONFIG_SCSI_FC_ATTRS now needs to select BLK_DEV_BSGLIB
in order to build correctly.

This patch is derived from work done by Mike Christie in 2011 [1] but only the
iscsi parts got merged back then.

[1] http://marc.info/?l=linux-scsi&m=131149780921009&w=2

Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
---
drivers/scsi/Kconfig | 1 +
drivers/scsi/scsi_transport_fc.c | 287 ++++++---------------------------------
2 files changed, 44 insertions(+), 244 deletions(-)

diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 7d1b431..1a0338c 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -263,6 +263,7 @@ config SCSI_SPI_ATTRS
config SCSI_FC_ATTRS
tristate "FiberChannel Transport Attributes"
depends on SCSI && NET
+ select BLK_DEV_BSGLIB
select SCSI_NETLINK
help
If you wish to export transport-specific information about
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 7fae045..916d488 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -3591,111 +3591,12 @@ fc_bsg_job_timeout(struct request *req)
return BLK_EH_HANDLED;
}

-static int
-fc_bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
-{
- size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
-
- BUG_ON(!req->nr_phys_segments);
-
- buf->sg_list = kzalloc(sz, GFP_KERNEL);
- if (!buf->sg_list)
- return -ENOMEM;
- sg_init_table(buf->sg_list, req->nr_phys_segments);
- buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
- buf->payload_len = blk_rq_bytes(req);
- return 0;
-}
-
-
-/**
- * fc_req_to_bsgjob - Allocate/create the fc_bsg_job structure for the
- * bsg request
- * @shost: SCSI Host corresponding to the bsg object
- * @rport: (optional) FC Remote Port corresponding to the bsg object
- * @req: BSG request that needs a job structure
- */
-static int
-fc_req_to_bsgjob(struct Scsi_Host *shost, struct fc_rport *rport,
- struct request *req)
-{
- struct fc_internal *i = to_fc_internal(shost->transportt);
- struct request *rsp = req->next_rq;
- struct bsg_job *job;
- struct fc_bsg_request *bsg_request;
- struct fc_bsg_reply *bsg_reply;
- int ret;
-
- BUG_ON(req->special);
-
- job = kzalloc(sizeof(struct bsg_job) + i->f->dd_bsg_size,
- GFP_KERNEL);
- if (!job)
- return -ENOMEM;
-
- /*
- * Note: this is a bit silly.
- * The request gets formatted as a SGIO v4 ioctl request, which
- * then gets reformatted as a blk request, which then gets
- * reformatted as a fc bsg request. And on completion, we have
- * to wrap return results such that SGIO v4 thinks it was a scsi
- * status. I hope this was all worth it.
- */
-
- req->special = job;
- job->req = req;
- if (i->f->dd_bsg_size)
- job->dd_data = (void *)&job[1];
- bsg_request = (struct fc_bsg_request *)req->cmd;
- job->request_len = req->cmd_len;
- bsg_reply = req->sense;
- job->reply_len = SCSI_SENSE_BUFFERSIZE; /* Size of sense buffer
- * allocated */
- if (req->bio) {
- ret = fc_bsg_map_buffer(&job->request_payload, req);
- if (ret)
- goto failjob_rls_job;
- }
- if (rsp && rsp->bio) {
- ret = fc_bsg_map_buffer(&job->reply_payload, rsp);
- if (ret)
- goto failjob_rls_rqst_payload;
- }
- if (rport)
- job->dev = &rport->dev;
- else
- job->dev = &shost->shost_gendev;
- get_device(job->dev); /* take a reference for the request */
-
- kref_init(&job->kref);
-
- return 0;
-
-
-failjob_rls_rqst_payload:
- kfree(job->request_payload.sg_list);
-failjob_rls_job:
- kfree(job);
- return -ENOMEM;
-}
-
-
-enum fc_dispatch_result {
- FC_DISPATCH_BREAK, /* on return, q is locked, break from q loop */
- FC_DISPATCH_LOCKED, /* on return, q is locked, continue on */
- FC_DISPATCH_UNLOCKED, /* on return, q is unlocked, continue on */
-};
-
-
/**
* fc_bsg_host_dispatch - process fc host bsg requests and dispatch to LLDD
- * @q: fc host request queue
* @shost: scsi host rport attached to
* @job: bsg job to be processed
*/
-static enum fc_dispatch_result
-fc_bsg_host_dispatch(struct request_queue *q, struct Scsi_Host *shost,
- struct bsg_job *job)
+static int fc_bsg_host_dispatch(struct Scsi_Host *shost, struct bsg_job *job)
{
struct fc_internal *i = to_fc_internal(shost->transportt);
struct fc_bsg_request *bsg_request = job->request;
@@ -3756,7 +3657,7 @@ fc_bsg_host_dispatch(struct request_queue *q, struct Scsi_Host *shost,

ret = i->f->bsg_request(job);
if (!ret)
- return FC_DISPATCH_UNLOCKED;
+ return 0;

fail_host_msg:
/* return the errno failure code as the only status */
@@ -3766,7 +3667,7 @@ fail_host_msg:
job->reply_len = sizeof(uint32_t);
bsg_job_done(job, bsg_reply->result,
bsg_reply->reply_payload_rcv_len);
- return FC_DISPATCH_UNLOCKED;
+ return 0;
}


@@ -3790,14 +3691,10 @@ fc_bsg_goose_queue(struct fc_rport *rport)

/**
* fc_bsg_rport_dispatch - process rport bsg requests and dispatch to LLDD
- * @q: rport request queue
* @shost: scsi host rport attached to
- * @rport: rport request destined to
* @job: bsg job to be processed
*/
-static enum fc_dispatch_result
-fc_bsg_rport_dispatch(struct request_queue *q, struct Scsi_Host *shost,
- struct fc_rport *rport, struct bsg_job *job)
+static int fc_bsg_rport_dispatch(struct Scsi_Host *shost, struct bsg_job *job)
{
struct fc_internal *i = to_fc_internal(shost->transportt);
struct fc_bsg_request *bsg_request = job->request;
@@ -3834,7 +3731,7 @@ check_bidi:

ret = i->f->bsg_request(job);
if (!ret)
- return FC_DISPATCH_UNLOCKED;
+ return 0;

fail_rport_msg:
/* return the errno failure code as the only status */
@@ -3844,119 +3741,19 @@ fail_rport_msg:
job->reply_len = sizeof(uint32_t);
bsg_job_done(job, bsg_reply->result,
bsg_reply->reply_payload_rcv_len);
- return FC_DISPATCH_UNLOCKED;
-}
-
-
-/**
- * fc_bsg_request_handler - generic handler for bsg requests
- * @q: request queue to manage
- * @shost: Scsi_Host related to the bsg object
- * @rport: FC remote port related to the bsg object (optional)
- * @dev: device structure for bsg object
- */
-static void
-fc_bsg_request_handler(struct request_queue *q, struct Scsi_Host *shost,
- struct fc_rport *rport, struct device *dev)
-{
- struct request *req;
- struct bsg_job *job;
- enum fc_dispatch_result ret;
- struct fc_bsg_reply *bsg_reply;
-
- if (!get_device(dev))
- return;
-
- while (1) {
- if (rport && (rport->port_state == FC_PORTSTATE_BLOCKED) &&
- !(rport->flags & FC_RPORT_FAST_FAIL_TIMEDOUT))
- break;
-
- req = blk_fetch_request(q);
- if (!req)
- break;
-
- if (rport && (rport->port_state != FC_PORTSTATE_ONLINE)) {
- req->errors = -ENXIO;
- spin_unlock_irq(q->queue_lock);
- blk_end_request_all(req, -ENXIO);
- spin_lock_irq(q->queue_lock);
- continue;
- }
-
- spin_unlock_irq(q->queue_lock);
-
- ret = fc_req_to_bsgjob(shost, rport, req);
- if (ret) {
- req->errors = ret;
- blk_end_request_all(req, ret);
- spin_lock_irq(q->queue_lock);
- continue;
- }
-
- job = req->special;
-
- /* check if we have the msgcode value at least */
- if (job->request_len < sizeof(uint32_t)) {
- BUG_ON(job->reply_len < sizeof(uint32_t));
- bsg_reply = job->reply;
- bsg_reply->reply_payload_rcv_len = 0;
- bsg_reply->result = -ENOMSG;
- job->reply_len = sizeof(uint32_t);
- bsg_job_done(job, bsg_reply->result,
- bsg_reply->reply_payload_rcv_len);
- spin_lock_irq(q->queue_lock);
- continue;
- }
-
- /* the dispatch routines will unlock the queue_lock */
- if (rport)
- ret = fc_bsg_rport_dispatch(q, shost, rport, job);
- else
- ret = fc_bsg_host_dispatch(q, shost, job);
-
- /* did dispatcher hit state that can't process any more */
- if (ret == FC_DISPATCH_BREAK)
- break;
-
- /* did dispatcher had released the lock */
- if (ret == FC_DISPATCH_UNLOCKED)
- spin_lock_irq(q->queue_lock);
- }
-
- spin_unlock_irq(q->queue_lock);
- put_device(dev);
- spin_lock_irq(q->queue_lock);
-}
-
-
-/**
- * fc_bsg_host_handler - handler for bsg requests for a fc host
- * @q: fc host request queue
- */
-static void
-fc_bsg_host_handler(struct request_queue *q)
-{
- struct Scsi_Host *shost = q->queuedata;
-
- fc_bsg_request_handler(q, shost, NULL, &shost->shost_gendev);
+ return 0;
}

-
-/**
- * fc_bsg_rport_handler - handler for bsg requests for a fc rport
- * @q: rport request queue
- */
-static void
-fc_bsg_rport_handler(struct request_queue *q)
+static int fc_bsg_dispatch(struct bsg_job *job)
{
- struct fc_rport *rport = q->queuedata;
- struct Scsi_Host *shost = rport_to_shost(rport);
+ struct Scsi_Host *shost = fc_bsg_to_shost(job);

- fc_bsg_request_handler(q, shost, rport, &rport->dev);
+ if (scsi_is_fc_rport(job->dev))
+ return fc_bsg_rport_dispatch(shost, job);
+ else
+ return fc_bsg_host_dispatch(shost, job);
}

-
/**
* fc_bsg_hostadd - Create and add the bsg hooks so we can receive requests
* @shost: shost for fc_host
@@ -3979,33 +3776,42 @@ fc_bsg_hostadd(struct Scsi_Host *shost, struct fc_host_attrs *fc_host)
snprintf(bsg_name, sizeof(bsg_name),
"fc_host%d", shost->host_no);

- q = __scsi_alloc_queue(shost, fc_bsg_host_handler);
+ q = __scsi_alloc_queue(shost, bsg_request_fn);
if (!q) {
- printk(KERN_ERR "fc_host%d: bsg interface failed to "
- "initialize - no request queue\n",
- shost->host_no);
+ dev_err(dev,
+ "fc_host%d: bsg interface failed to initialize - no request queue\n",
+ shost->host_no);
return -ENOMEM;
}

- q->queuedata = shost;
- queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q);
- blk_queue_softirq_done(q, bsg_softirq_done);
- blk_queue_rq_timed_out(q, fc_bsg_job_timeout);
- blk_queue_rq_timeout(q, FC_DEFAULT_BSG_TIMEOUT);
-
- err = bsg_register_queue(q, dev, bsg_name, NULL);
+ err = bsg_setup_queue(dev, q, bsg_name, fc_bsg_dispatch,
+ i->f->dd_bsg_size);
if (err) {
- printk(KERN_ERR "fc_host%d: bsg interface failed to "
- "initialize - register queue\n",
- shost->host_no);
+ dev_err(dev,
+ "fc_host%d: bsg interface failed to initialize - setup queue\n",
+ shost->host_no);
blk_cleanup_queue(q);
return err;
}
-
+ blk_queue_rq_timed_out(q, fc_bsg_job_timeout);
+ blk_queue_rq_timeout(q, FC_DEFAULT_BSG_TIMEOUT);
fc_host->rqst_q = q;
return 0;
}

+static int fc_bsg_rport_prep(struct request_queue *q, struct request *req)
+{
+ struct fc_rport *rport = dev_to_rport(q->queuedata);
+
+ if (rport->port_state == FC_PORTSTATE_BLOCKED &&
+ !(rport->flags & FC_RPORT_FAST_FAIL_TIMEDOUT))
+ return BLKPREP_DEFER;
+
+ if (rport->port_state != FC_PORTSTATE_ONLINE)
+ return BLKPREP_KILL;
+
+ return BLKPREP_OK;
+}

/**
* fc_bsg_rportadd - Create and add the bsg hooks so we can receive requests
@@ -4025,29 +3831,22 @@ fc_bsg_rportadd(struct Scsi_Host *shost, struct fc_rport *rport)
if (!i->f->bsg_request)
return -ENOTSUPP;

- q = __scsi_alloc_queue(shost, fc_bsg_rport_handler);
+ q = __scsi_alloc_queue(shost, bsg_request_fn);
if (!q) {
- printk(KERN_ERR "%s: bsg interface failed to "
- "initialize - no request queue\n",
- dev->kobj.name);
+ dev_err(dev, "bsg interface failed to initialize - no request queue\n");
return -ENOMEM;
}

- q->queuedata = rport;
- queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q);
- blk_queue_softirq_done(q, bsg_softirq_done);
- blk_queue_rq_timed_out(q, fc_bsg_job_timeout);
- blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
-
- err = bsg_register_queue(q, dev, NULL, NULL);
+ err = bsg_setup_queue(dev, q, NULL, fc_bsg_dispatch, i->f->dd_bsg_size);
if (err) {
- printk(KERN_ERR "%s: bsg interface failed to "
- "initialize - register queue\n",
- dev->kobj.name);
+ dev_err(dev, "failed to setup bsg queue\n");
blk_cleanup_queue(q);
return err;
}

+ blk_queue_prep_rq(q, fc_bsg_rport_prep);
+ blk_queue_rq_timed_out(q, fc_bsg_job_timeout);
+ blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
rport->rqst_q = q;
return 0;
}
--
1.8.5.6