Commit 17cb960f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe

bsg: split handling of SCSI CDBs vs transport requeues

The current BSG design tries to shoe-horn the transport-specific
passthrough commands into the overall framework for SCSI passthrough
requests.  This has a couple problems:

 - each passthrough queue has to set the QUEUE_FLAG_SCSI_PASSTHROUGH flag
   despite not dealing with SCSI commands at all.  Because of that these
   queues could also incorrectly accept SCSI commands from in-kernel
   users or through the legacy SCSI_IOCTL_SEND_COMMAND ioctl.
 - the real SCSI bsg queues also incorrectly accept bsg requests of the
   BSG_SUB_PROTOCOL_SCSI_TRANSPORT type
 - the bsg transport code is almost unredable because it tries to reuse
   different SCSI concepts for its own purpose.

This patch instead adds a new bsg_ops structure to handle the two cases
differently, and thus solves all of the above problems.  Another side
effect is that the bsg-lib queues also don't need to embedd a
struct scsi_request anymore.
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ef6fa64f
......@@ -27,6 +27,94 @@
#include <linux/bsg-lib.h>
#include <linux/export.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/sg.h>
#define uptr64(val) ((void __user *)(uintptr_t)(val))
static int bsg_transport_check_proto(struct sg_io_v4 *hdr)
{
if (hdr->protocol != BSG_PROTOCOL_SCSI ||
hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT)
return -EINVAL;
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
return 0;
}
static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
fmode_t mode)
{
struct bsg_job *job = blk_mq_rq_to_pdu(rq);
job->request_len = hdr->request_len;
job->request = memdup_user(uptr64(hdr->request), hdr->request_len);
if (IS_ERR(job->request))
return PTR_ERR(job->request);
return 0;
}
static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
{
struct bsg_job *job = blk_mq_rq_to_pdu(rq);
int ret = 0;
/*
* The assignments below don't make much sense, but are kept for
* bug by bug backwards compatibility:
*/
hdr->device_status = job->result & 0xff;
hdr->transport_status = host_byte(job->result);
hdr->driver_status = driver_byte(job->result);
hdr->info = 0;
if (hdr->device_status || hdr->transport_status || hdr->driver_status)
hdr->info |= SG_INFO_CHECK;
hdr->response_len = 0;
if (job->result < 0) {
/* we're only returning the result field in the reply */
job->reply_len = sizeof(u32);
ret = job->result;
}
if (job->reply_len && hdr->response) {
int len = min(hdr->max_response_len, job->reply_len);
if (copy_to_user(uptr64(hdr->response), job->reply, len))
ret = -EFAULT;
else
hdr->response_len = len;
}
/* we assume all request payload was transferred, residual == 0 */
hdr->dout_resid = 0;
if (rq->next_rq) {
unsigned int rsp_len = job->reply_payload.payload_len;
if (WARN_ON(job->reply_payload_rcv_len > rsp_len))
hdr->din_resid = 0;
else
hdr->din_resid = rsp_len - job->reply_payload_rcv_len;
} else {
hdr->din_resid = 0;
}
return ret;
}
static void bsg_transport_free_rq(struct request *rq)
{
struct bsg_job *job = blk_mq_rq_to_pdu(rq);
kfree(job->request);
}
static const struct bsg_ops bsg_transport_ops = {
.check_proto = bsg_transport_check_proto,
.fill_hdr = bsg_transport_fill_hdr,
.complete_rq = bsg_transport_complete_rq,
.free_rq = bsg_transport_free_rq,
};
/**
* bsg_teardown_job - routine to teardown a bsg job
......@@ -68,27 +156,9 @@ EXPORT_SYMBOL_GPL(bsg_job_get);
void bsg_job_done(struct bsg_job *job, int result,
unsigned int reply_payload_rcv_len)
{
struct request *req = blk_mq_rq_from_pdu(job);
struct request *rsp = req->next_rq;
int err;
err = job->sreq.result = result;
if (err < 0)
/* we're only returning the result field in the reply */
job->sreq.sense_len = sizeof(u32);
else
job->sreq.sense_len = job->reply_len;
/* we assume all request payload was transferred, residual == 0 */
job->sreq.resid_len = 0;
if (rsp) {
WARN_ON(reply_payload_rcv_len > scsi_req(rsp)->resid_len);
/* set reply (bidi) residual */
scsi_req(rsp)->resid_len -=
min(reply_payload_rcv_len, scsi_req(rsp)->resid_len);
}
blk_complete_request(req);
job->result = result;
job->reply_payload_rcv_len = reply_payload_rcv_len;
blk_complete_request(blk_mq_rq_from_pdu(job));
}
EXPORT_SYMBOL_GPL(bsg_job_done);
......@@ -113,7 +183,6 @@ static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
if (!buf->sg_list)
return -ENOMEM;
sg_init_table(buf->sg_list, req->nr_phys_segments);
scsi_req(req)->resid_len = blk_rq_bytes(req);
buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
buf->payload_len = blk_rq_bytes(req);
return 0;
......@@ -124,16 +193,13 @@ static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
* @dev: device that is being sent the bsg request
* @req: BSG request that needs a job structure
*/
static int bsg_prepare_job(struct device *dev, struct request *req)
static bool bsg_prepare_job(struct device *dev, struct request *req)
{
struct request *rsp = req->next_rq;
struct scsi_request *rq = scsi_req(req);
struct bsg_job *job = blk_mq_rq_to_pdu(req);
int ret;
job->timeout = req->timeout;
job->request = rq->cmd;
job->request_len = rq->cmd_len;
if (req->bio) {
ret = bsg_map_buffer(&job->request_payload, req);
......@@ -149,12 +215,13 @@ static int bsg_prepare_job(struct device *dev, struct request *req)
/* take a reference for the request */
get_device(job->dev);
kref_init(&job->kref);
return 0;
return true;
failjob_rls_rqst_payload:
kfree(job->request_payload.sg_list);
failjob_rls_job:
return -ENOMEM;
job->result = -ENOMEM;
return false;
}
/**
......@@ -183,9 +250,7 @@ static void bsg_request_fn(struct request_queue *q)
break;
spin_unlock_irq(q->queue_lock);
ret = bsg_prepare_job(dev, req);
if (ret) {
scsi_req(req)->result = ret;
if (!bsg_prepare_job(dev, req)) {
blk_end_request_all(req, BLK_STS_OK);
spin_lock_irq(q->queue_lock);
continue;
......@@ -202,46 +267,34 @@ static void bsg_request_fn(struct request_queue *q)
spin_lock_irq(q->queue_lock);
}
/* called right after the request is allocated for the request_queue */
static int bsg_init_rq(struct request_queue *q, struct request *req, gfp_t gfp)
{
struct bsg_job *job = blk_mq_rq_to_pdu(req);
struct scsi_request *sreq = &job->sreq;
/* called right after the request is allocated for the request_queue */
sreq->sense = kzalloc(SCSI_SENSE_BUFFERSIZE, gfp);
if (!sreq->sense)
job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, gfp);
if (!job->reply)
return -ENOMEM;
return 0;
}
/* called right before the request is given to the request_queue user */
static void bsg_initialize_rq(struct request *req)
{
struct bsg_job *job = blk_mq_rq_to_pdu(req);
struct scsi_request *sreq = &job->sreq;
void *sense = sreq->sense;
/* called right before the request is given to the request_queue user */
void *reply = job->reply;
memset(job, 0, sizeof(*job));
scsi_req_init(sreq);
sreq->sense = sense;
sreq->sense_len = SCSI_SENSE_BUFFERSIZE;
job->reply = sense;
job->reply_len = sreq->sense_len;
job->reply = reply;
job->reply_len = SCSI_SENSE_BUFFERSIZE;
job->dd_data = job + 1;
}
static void bsg_exit_rq(struct request_queue *q, struct request *req)
{
struct bsg_job *job = blk_mq_rq_to_pdu(req);
struct scsi_request *sreq = &job->sreq;
kfree(sreq->sense);
kfree(job->reply);
}
/**
......@@ -275,11 +328,10 @@ struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
q->queuedata = dev;
q->bsg_job_fn = job_fn;
blk_queue_flag_set(QUEUE_FLAG_BIDI, q);
blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
blk_queue_softirq_done(q, bsg_softirq_done);
blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
ret = bsg_register_queue(q, dev, name, release);
ret = bsg_register_queue(q, dev, name, &bsg_transport_ops, release);
if (ret) {
printk(KERN_ERR "%s: bsg interface failed to "
"initialize - register queue\n", dev->kobj.name);
......
This diff is collapsed.
......@@ -2140,8 +2140,6 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
{
struct device *dev = shost->dma_dev;
blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
/*
* this limit is imposed by hardware restrictions
*/
......@@ -2239,6 +2237,7 @@ struct request_queue *scsi_old_alloc_queue(struct scsi_device *sdev)
}
__scsi_init_queue(shost, q);
blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
blk_queue_prep_rq(q, scsi_prep_fn);
blk_queue_unprep_rq(q, scsi_unprep_fn);
blk_queue_softirq_done(q, scsi_softirq_done);
......@@ -2270,6 +2269,7 @@ struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
sdev->request_queue->queuedata = sdev;
__scsi_init_queue(sdev->host, sdev->request_queue);
blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue);
return sdev->request_queue;
}
......
......@@ -1292,8 +1292,7 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
transport_add_device(&sdev->sdev_gendev);
sdev->is_visible = 1;
error = bsg_register_queue(rq, &sdev->sdev_gendev, NULL, NULL);
error = bsg_scsi_register_queue(rq, &sdev->sdev_gendev);
if (error)
/* we're treating error on bsg register as non-fatal,
* so pretend nothing went wrong */
......
......@@ -228,7 +228,6 @@ static int sas_bsg_initialize(struct Scsi_Host *shost, struct sas_rphy *rphy)
*/
blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
blk_queue_flag_set(QUEUE_FLAG_BIDI, q);
blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
return 0;
}
......
......@@ -38,7 +38,6 @@ struct bsg_buffer {
};
struct bsg_job {
struct scsi_request sreq;
struct device *dev;
struct kref kref;
......@@ -64,6 +63,9 @@ struct bsg_job {
struct bsg_buffer request_payload;
struct bsg_buffer reply_payload;
int result;
unsigned int reply_payload_rcv_len;
void *dd_data; /* Used for driver-specific storage */
};
......
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef BSG_H
#define BSG_H
#ifndef _LINUX_BSG_H
#define _LINUX_BSG_H
#include <uapi/linux/bsg.h>
struct request;
#ifdef CONFIG_BLK_DEV_BSG
struct bsg_ops {
int (*check_proto)(struct sg_io_v4 *hdr);
int (*fill_hdr)(struct request *rq, struct sg_io_v4 *hdr,
fmode_t mode);
int (*complete_rq)(struct request *rq, struct sg_io_v4 *hdr);
void (*free_rq)(struct request *rq);
};
#if defined(CONFIG_BLK_DEV_BSG)
struct bsg_class_device {
struct device *class_dev;
struct device *parent;
int minor;
struct request_queue *queue;
struct kref ref;
const struct bsg_ops *ops;
void (*release)(struct device *);
};
extern int bsg_register_queue(struct request_queue *q,
struct device *parent, const char *name,
int bsg_register_queue(struct request_queue *q, struct device *parent,
const char *name, const struct bsg_ops *ops,
void (*release)(struct device *));
extern void bsg_unregister_queue(struct request_queue *);
int bsg_scsi_register_queue(struct request_queue *q, struct device *parent);
void bsg_unregister_queue(struct request_queue *q);
#else
static inline int bsg_register_queue(struct request_queue *q,
struct device *parent, const char *name,
void (*release)(struct device *))
static inline int bsg_scsi_register_queue(struct request_queue *q,
struct device *parent)
{
return 0;
}
static inline void bsg_unregister_queue(struct request_queue *q)
{
}
#endif
#endif
#endif /* CONFIG_BLK_DEV_BSG */
#endif /* _LINUX_BSG_H */
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment