| From: |
| James Smart <James.Smart@Emulex.Com> |
| To: |
| <linux-scsi@vger.kernel.org> |
| Subject: |
| [RFC] iscsi transport : add sgio pass-thru support |
| Date: |
| Thu, 29 Oct 2009 17:50:36 -0400 |
This patch implements the same infrastructure as found in the FC transport
for sgio request/response handling.
The patch creates (and exports to userland) a new header - scsi_bsg_iscsi.h
-- james s
Signed-off-by: James Smart <james.smart@emulex.com>
---
drivers/scsi/scsi_transport_iscsi.c | 414 +++++++++++++++++++++++++++++++++++-
include/scsi/Kbuild | 1
include/scsi/scsi_bsg_iscsi.h | 111 +++++++++
include/scsi/scsi_transport_iscsi.h | 45 +++
4 files changed, 570 insertions(+), 1 deletion(-)
diff -upNr a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
--- a/drivers/scsi/scsi_transport_iscsi.c 2009-10-26 12:58:17.000000000 -0400
+++ b/drivers/scsi/scsi_transport_iscsi.c 2009-10-29 15:00:57.000000000 -0400
@@ -29,6 +29,8 @@
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_iscsi.h>
#include <scsi/iscsi_if.h>
+#include <scsi/scsi_bsg_iscsi.h>
+#include <scsi/scsi_cmnd.h>
#define ISCSI_SESSION_ATTRS 21
#define ISCSI_CONN_ATTRS 13
@@ -268,6 +270,402 @@ struct iscsi_endpoint *iscsi_lookup_endp
}
EXPORT_SYMBOL_GPL(iscsi_lookup_endpoint);
+
+/*
+ * BSG support
+ */
+
+/**
+ * iscsi_destroy_bsgjob - routine to teardown/delete a iscsi bsg job
+ * @job: iscsi_bsg_job that is to be torn down
+ */
+static void
+iscsi_destroy_bsgjob(struct iscsi_bsg_job *job)
+{
+ unsigned long flags;
+
+ 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);
+
+ put_device(job->dev); /* release reference for the request */
+
+ kfree(job->request_payload.sg_list);
+ kfree(job->reply_payload.sg_list);
+ kfree(job);
+}
+
+/**
+ * iscsi_bsg_jobdone - completion routine for bsg requests that the LLD has
+ * completed
+ * @job: iscsi_bsg_job that is complete
+ */
+static void
+iscsi_bsg_jobdone(struct iscsi_bsg_job *job)
+{
+ struct request *req = job->req;
+ struct request *rsp = req->next_rq;
+ int err;
+
+ err = job->req->errors = job->reply->result;
+
+ if (err < 0)
+ /* we're only returning the result field in the reply */
+ job->req->sense_len = sizeof(uint32_t);
+ else
+ job->req->sense_len = job->reply_len;
+
+ /* we assume all request payload was transferred, residual == 0 */
+ req->resid_len = 0;
+
+ if (rsp) {
+ WARN_ON(job->reply->reply_payload_rcv_len > rsp->resid_len);
+
+ /* set reply (bidi) residual */
+ rsp->resid_len -= min(job->reply->reply_payload_rcv_len,
+ rsp->resid_len);
+ }
+ blk_complete_request(req);
+}
+
+/**
+ * iscsi_bsg_softirq_done - softirq done routine for destroying the bsg requests
+ * @rq: BSG request that holds the job to be destroyed
+ */
+static void
+iscsi_bsg_softirq_done(struct request *rq)
+{
+ struct iscsi_bsg_job *job = rq->special;
+ unsigned long flags;
+
+ spin_lock_irqsave(&job->job_lock, flags);
+ job->state_flags |= ISCSI_RQST_STATE_DONE;
+ job->ref_cnt--;
+ spin_unlock_irqrestore(&job->job_lock, flags);
+
+ blk_end_request_all(rq, rq->errors);
+ iscsi_destroy_bsgjob(job);
+}
+
+/**
+ * iscsi_bsg_job_timeout - handler for when a bsg request timesout
+ * @req: request that timed out
+ */
+static enum blk_eh_timer_return
+iscsi_bsg_job_timeout(struct request *req)
+{
+ struct iscsi_bsg_job *job = (void *) req->special;
+ struct Scsi_Host *shost = job->shost;
+ struct iscsi_internal *i = to_iscsi_internal(shost->transportt);
+ unsigned long flags;
+ int err = 0, done = 0;
+
+ spin_lock_irqsave(&job->job_lock, flags);
+ if (job->state_flags & ISCSI_RQST_STATE_DONE)
+ done = 1;
+ else
+ job->ref_cnt++;
+ spin_unlock_irqrestore(&job->job_lock, flags);
+
+ if (!done && i->iscsi_transport->bsg_timeout) {
+ /* call LLDD to abort the i/o as it has timed out */
+ err = i->iscsi_transport->bsg_timeout(job);
+ if (err)
+ printk(KERN_ERR "ERROR: iSCSI BSG request timeout - "
+ "LLD abort failed with status %d\n", err);
+ }
+
+ /* the blk_end_sync_io() doesn't check the error */
+ if (done)
+ return BLK_EH_NOT_HANDLED;
+ else
+ return BLK_EH_HANDLED;
+}
+
+static int
+iscsi_bsg_map_buffer(struct iscsi_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;
+}
+
+/**
+ * iscsi_req_to_bsgjob - Allocate/create the iscsi_bsg_job structure for the
+ * bsg request
+ * @req: BSG request that needs a job structure
+ * @shost: SCSI Host corresponding to the bsg object
+ */
+static int
+iscsi_req_to_bsgjob(struct request *req, struct Scsi_Host *shost)
+{
+ struct iscsi_internal *i = to_iscsi_internal(shost->transportt);
+ struct request *rsp = req->next_rq;
+ struct iscsi_bsg_job *job;
+ int ret;
+
+ BUG_ON(req->special);
+
+ job = kzalloc(sizeof(struct iscsi_bsg_job) +
+ i->iscsi_transport->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 iscsi 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->shost = shost;
+ job->req = req;
+ if (i->iscsi_transport->dd_bsg_size)
+ job->dd_data = (void *)&job[1];
+ spin_lock_init(&job->job_lock);
+ job->request = (struct iscsi_bsg_request *)req->cmd;
+ job->request_len = req->cmd_len;
+ job->reply = req->sense;
+ job->reply_len = SCSI_SENSE_BUFFERSIZE; /* Size of sense buffer
+ * allocated */
+ if (req->bio) {
+ ret = iscsi_bsg_map_buffer(&job->request_payload, req);
+ if (ret)
+ goto failjob_rls_job;
+ }
+ if (rsp && rsp->bio) {
+ ret = iscsi_bsg_map_buffer(&job->reply_payload, rsp);
+ if (ret)
+ goto failjob_rls_rqst_payload;
+ }
+ job->job_done = iscsi_bsg_jobdone;
+ job->dev = &shost->shost_gendev;
+ get_device(job->dev); /* take a reference for the request */
+
+ job->ref_cnt = 1;
+
+ return 0;
+
+
+failjob_rls_rqst_payload:
+ kfree(job->request_payload.sg_list);
+failjob_rls_job:
+ kfree(job);
+ return -ENOMEM;
+}
+
+
+enum iscsi_dispatch_result {
+ DISPATCH_BREAK, /* on return, q is locked, break from q loop */
+ DISPATCH_LOCKED, /* on return, q is locked, continue on */
+ DISPATCH_UNLOCKED, /* on return, q is unlocked, continue on */
+};
+
+/**
+ * iscsi_bsg_host_dispatch - process iscsi host bsg requests and
+ * dispatch to LLDD
+ * @q: iscsi host request queue
+ * @shost: scsi host request queue attached to
+ * @job: bsg job to be processed
+ */
+static enum iscsi_dispatch_result
+iscsi_bsg_host_dispatch(struct request_queue *q, struct Scsi_Host *shost,
+ struct iscsi_bsg_job *job)
+{
+ struct iscsi_internal *i = to_iscsi_internal(shost->transportt);
+ int cmdlen = sizeof(uint32_t); /* start with length of msgcode */
+ int ret;
+
+ /* Validate the host command */
+ switch (job->request->msgcode) {
+ case ISCSI_BSG_HST_VENDOR:
+ cmdlen += sizeof(struct iscsi_bsg_host_vendor);
+ if ((shost->hostt->vendor_id == 0L) ||
+ (job->request->rqst_data.h_vendor.vendor_id !=
+ shost->hostt->vendor_id)) {
+ ret = -ESRCH;
+ goto fail_host_msg;
+ }
+ break;
+
+ default:
+ ret = -EBADR;
+ goto fail_host_msg;
+ }
+
+ /* check if we really have all the request data needed */
+ if (job->request_len < cmdlen) {
+ ret = -ENOMSG;
+ goto fail_host_msg;
+ }
+
+ ret = i->iscsi_transport->bsg_request(job);
+ if (!ret)
+ return DISPATCH_UNLOCKED;
+
+fail_host_msg:
+ /* return the errno failure code as the only status */
+ BUG_ON(job->reply_len < sizeof(uint32_t));
+ job->reply->result = ret;
+ job->reply_len = sizeof(uint32_t);
+ iscsi_bsg_jobdone(job);
+ return DISPATCH_UNLOCKED;
+}
+
+/**
+ * iscsi_bsg_request_handler - generic handler for bsg requests
+ * @q: request queue to manage
+ * @shost: Scsi_Host related to the bsg object
+ * @dev: device structure for bsg object
+ *
+ * NOTE: only shost messages are expected
+ */
+static void
+iscsi_bsg_request_handler(struct request_queue *q, struct Scsi_Host *shost,
+ struct device *dev)
+{
+ struct request *req;
+ struct iscsi_bsg_job *job;
+ enum iscsi_dispatch_result ret;
+
+ if (!get_device(dev))
+ return;
+
+ while (!blk_queue_plugged(q)) {
+
+ req = blk_fetch_request(q);
+ if (!req)
+ break;
+
+ spin_unlock_irq(q->queue_lock);
+
+ ret = iscsi_req_to_bsgjob(req, shost);
+ if (ret) {
+ req->errors = ret;
+ blk_end_request(req, ret, blk_rq_bytes(req));
+ 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));
+ job->reply->result = -ENOMSG;
+ job->reply_len = sizeof(uint32_t);
+ iscsi_bsg_jobdone(job);
+ spin_lock_irq(q->queue_lock);
+ continue;
+ }
+
+ /* the dispatch routines will unlock the queue_lock */
+ iscsi_bsg_host_dispatch(q, shost, job);
+
+ /* did dispatcher hit state that can't process any more */
+ if (ret == DISPATCH_BREAK)
+ break;
+
+ /* did dispatcher had released the lock */
+ if (ret == DISPATCH_UNLOCKED)
+ spin_lock_irq(q->queue_lock);
+ }
+
+ spin_unlock_irq(q->queue_lock);
+ put_device(dev);
+ spin_lock_irq(q->queue_lock);
+}
+
+/**
+ * iscsi_bsg_host_handler - handler for bsg requests for a iscsi host
+ * @q: iscsi host request queue
+ */
+static void
+iscsi_bsg_host_handler(struct request_queue *q)
+{
+ struct Scsi_Host *shost = q->queuedata;
+
+ iscsi_bsg_request_handler(q, shost, &shost->shost_gendev);
+}
+
+/**
+ * iscsi_bsg_hostadd - Create and add the bsg hooks so we can receive requests
+ * @shost: shost for iscsi_host
+ * @cls_host: iscsi_cls_host adding the structures to
+ */
+static int
+iscsi_bsg_hostadd(struct Scsi_Host *shost, struct iscsi_cls_host *ihost)
+{
+ struct device *dev = &shost->shost_gendev;
+ struct iscsi_internal *i = to_iscsi_internal(shost->transportt);
+ struct request_queue *q;
+ int err;
+ char bsg_name[20];
+
+ ihost->rqst_q = NULL;
+
+ if (!i->iscsi_transport->bsg_request)
+ return -ENOTSUPP;
+
+ snprintf(bsg_name, sizeof(bsg_name),
+ "iscsi_host%d", shost->host_no);
+
+ q = __scsi_alloc_queue(shost, iscsi_bsg_host_handler);
+ if (!q) {
+ printk(KERN_ERR "iscsi_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, iscsi_bsg_softirq_done);
+ blk_queue_rq_timed_out(q, iscsi_bsg_job_timeout);
+ blk_queue_rq_timeout(q, ISCSI_DEFAULT_BSG_TIMEOUT);
+
+ err = bsg_register_queue(q, dev, bsg_name, NULL);
+ if (err) {
+ printk(KERN_ERR "iscsi_host%d: bsg interface failed to "
+ "initialize - register queue\n",
+ shost->host_no);
+ blk_cleanup_queue(q);
+ return err;
+ }
+
+ ihost->rqst_q = q;
+ return 0;
+}
+
+/**
+ * iscsi_bsg_remove - Deletes the bsg hooks on iscsi objects
+ * @q: the request_queue that is to be torn down.
+ */
+static void
+iscsi_bsg_remove(struct request_queue *q)
+{
+ if (q) {
+ bsg_unregister_queue(q);
+ blk_cleanup_queue(q);
+ }
+}
+
+/* End BSG routines */
+
static int iscsi_setup_host(struct transport_container *tc, struct device *dev,
struct device *cdev)
{
@@ -277,13 +675,27 @@ static int iscsi_setup_host(struct trans
memset(ihost, 0, sizeof(*ihost));
atomic_set(&ihost->nr_scans, 0);
mutex_init(&ihost->mutex);
+
+ iscsi_bsg_hostadd(shost, ihost);
+ /* ignore any bsg add error - we just can't do sgio */
+
+ return 0;
+}
+
+static int iscsi_remove_host(struct transport_container *tc, struct device *dev,
+ struct device *cdev)
+{
+ struct Scsi_Host *shost = dev_to_shost(dev);
+ struct iscsi_cls_host *ihost = shost->shost_data;
+
+ iscsi_bsg_remove(ihost->rqst_q);
return 0;
}
static DECLARE_TRANSPORT_CLASS(iscsi_host_class,
"iscsi_host",
iscsi_setup_host,
- NULL,
+ iscsi_remove_host,
NULL);
static DECLARE_TRANSPORT_CLASS(iscsi_session_class,
diff -upNr a/include/scsi/Kbuild b/include/scsi/Kbuild
--- a/include/scsi/Kbuild 2009-10-26 12:58:28.000000000 -0400
+++ b/include/scsi/Kbuild 2009-10-28 09:17:36.000000000 -0400
@@ -2,3 +2,4 @@ header-y += scsi.h
header-y += scsi_netlink.h
header-y += scsi_netlink_fc.h
header-y += scsi_bsg_fc.h
+header-y += scsi_bsg_iscsi.h
diff -upNr a/include/scsi/scsi_bsg_iscsi.h b/include/scsi/scsi_bsg_iscsi.h
--- a/include/scsi/scsi_bsg_iscsi.h 1969-12-31 19:00:00.000000000 -0500
+++ b/include/scsi/scsi_bsg_iscsi.h 2009-10-29 14:29:31.000000000 -0400
@@ -0,0 +1,111 @@
+/*
+ * iSCSI Transport BSG Interface
+ *
+ * Copyright (C) 2009 James Smart, Emulex Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#ifndef SCSI_BSG_ISCSI_H
+#define SCSI_BSG_ISCSI_H
+
+/*
+ * This file intended to be included by both kernel and user space
+ */
+
+#include <scsi/scsi.h>
+
+/*
+ * iSCSI Transport SGIO v4 BSG Message Support
+ */
+
+/* Default BSG request timeout (in seconds) */
+#define ISCSI_DEFAULT_BSG_TIMEOUT (10 * HZ)
+
+
+/*
+ * Request Message Codes supported by the iSCSI Transport
+ */
+
+/* define the class masks for the message codes */
+#define ISCSI_BSG_CLS_MASK 0xF0000000 /* find object class */
+#define ISCSI_BSG_HST_MASK 0x80000000 /* iscsi host class */
+
+ /* iscsi host Message Codes */
+#define ISCSI_BSG_HST_VENDOR (ISCSI_BSG_HST_MASK | 0x000000FF)
+
+
+/*
+ * iSCSI Host Messages
+ */
+
+/* ISCSI_BSG_HST_VENDOR : */
+
+/* Request:
+ * Note: When specifying vendor_id, be sure to read the Vendor Type and ID
+ * formatting requirements specified in scsi_netlink.h
+ */
+struct iscsi_bsg_host_vendor {
+ /*
+ * Identifies the vendor that the message is formatted for. This
+ * should be the recipient of the message.
+ */
+ uint64_t vendor_id;
+
+ /* start of vendor command area */
+ uint32_t vendor_cmd[0];
+};
+
+/* Response:
+ */
+struct iscsi_bsg_host_vendor_reply {
+ /* start of vendor response area */
+ uint32_t vendor_rsp[0];
+};
+
+
+/* request (CDB) structure of the sg_io_v4 */
+struct iscsi_bsg_request {
+ uint32_t msgcode;
+ union {
+ struct iscsi_bsg_host_vendor h_vendor;
+ } rqst_data;
+};
+
+
+/* response (request sense data) structure of the sg_io_v4 */
+struct iscsi_bsg_reply {
+ /*
+ * The completion result. Result exists in two forms:
+ * if negative, it is an -Exxx system errno value. There will
+ * be no further reply information supplied.
+ * else, it's the 4-byte scsi error result, with driver, host,
+ * msg and status fields. The per-msgcode reply structure
+ * will contain valid data.
+ */
+ uint32_t result;
+
+ /* If there was reply_payload, how much was recevied ? */
+ uint32_t reply_payload_rcv_len;
+
+ union {
+ struct iscsi_bsg_host_vendor_reply vendor_reply;
+ } reply_data;
+};
+
+
+#endif /* SCSI_BSG_ISCSI_H */
+
diff -upNr a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
--- a/include/scsi/scsi_transport_iscsi.h 2009-10-26 12:58:28.000000000 -0400
+++ b/include/scsi/scsi_transport_iscsi.h 2009-10-29 14:55:04.000000000 -0400
@@ -37,6 +37,45 @@ struct iscsi_conn;
struct iscsi_task;
struct sockaddr;
+struct iscsi_bsg_buffer {
+ unsigned int payload_len;
+ int sg_cnt;
+ struct scatterlist *sg_list;
+};
+
+/* Values for iscsi_bsg_job->state_flags (bitflags) */
+#define ISCSI_RQST_STATE_INPROGRESS 0
+#define ISCSI_RQST_STATE_DONE 1
+
+struct iscsi_bsg_job {
+ struct Scsi_Host *shost;
+ struct device *dev;
+ struct request *req;
+ spinlock_t job_lock;
+ unsigned int state_flags;
+ unsigned int ref_cnt;
+ void (*job_done)(struct iscsi_bsg_job *);
+
+ struct iscsi_bsg_request *request;
+ struct iscsi_bsg_reply *reply;
+ unsigned int request_len;
+ unsigned int reply_len;
+ /*
+ * On entry : reply_len indicates the buffer size allocated for
+ * the reply.
+ *
+ * Upon completion : the message handler must set reply_len
+ * to indicates the size of the reply to be returned to the
+ * caller.
+ */
+
+ /* DMA payloads for the request/response */
+ struct iscsi_bsg_buffer request_payload;
+ struct iscsi_bsg_buffer reply_payload;
+
+ void *dd_data; /* Used for driver-specific storage */
+};
+
/**
* struct iscsi_transport - iSCSI Transport template
*
@@ -134,6 +173,11 @@ struct iscsi_transport {
int (*tgt_dscvr) (struct Scsi_Host *shost, enum iscsi_tgt_dscvr type,
uint32_t enable, struct sockaddr *dst_addr);
int (*set_path) (struct Scsi_Host *shost, struct iscsi_path *params);
+
+ /* bsg support */
+ int (*bsg_request)(struct iscsi_bsg_job *);
+ int (*bsg_timeout)(struct iscsi_bsg_job *);
+ u32 dd_bsg_size; /* allocation length for host-specific data */
};
/*
@@ -212,6 +256,7 @@ struct iscsi_cls_session {
struct iscsi_cls_host {
atomic_t nr_scans;
struct mutex mutex;
+ struct request_queue *rqst_q; /* bsg support */
};
extern void iscsi_host_for_each_session(struct Scsi_Host *shost,
--
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