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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* BSG helper library
*
* Copyright (C) 2008 James Smart, Emulex Corporation
* Copyright (C) 2011 Red Hat, Inc. All rights reserved.
* Copyright (C) 2011 Mike Christie
*/
#include <linux/slab.h>
#include <linux/blk-mq.h>
#include <linux/delay.h>
#include <linux/scatterlist.h>
#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))
struct bsg_set {
struct blk_mq_tag_set tag_set;
bsg_job_fn *job_fn;
bsg_timeout_fn *timeout_fn;
};
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);
int ret;
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);
if (hdr->dout_xfer_len && hdr->din_xfer_len) {
job->bidi_rq = blk_get_request(rq->q, REQ_OP_SCSI_IN, 0);
if (IS_ERR(job->bidi_rq)) {
ret = PTR_ERR(job->bidi_rq);
goto out;
}
ret = blk_rq_map_user(rq->q, job->bidi_rq, NULL,
uptr64(hdr->din_xferp), hdr->din_xfer_len,
GFP_KERNEL);
if (ret)
goto out_free_bidi_rq;
job->bidi_bio = job->bidi_rq->bio;
} else {
job->bidi_rq = NULL;
job->bidi_bio = NULL;
}
return 0;
out_free_bidi_rq:
if (job->bidi_rq)
blk_put_request(job->bidi_rq);
out:
kfree(job->request);
return ret;
}
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 (job->bidi_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);
if (job->bidi_rq) {
blk_rq_unmap_user(job->bidi_bio);
blk_put_request(job->bidi_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
* @kref: kref inside bsg_job that is to be torn down
*/
static void bsg_teardown_job(struct kref *kref)
{
struct bsg_job *job = container_of(kref, struct bsg_job, kref);
struct request *rq = blk_mq_rq_from_pdu(job);
put_device(job->dev); /* release reference for the request */
kfree(job->request_payload.sg_list);
kfree(job->reply_payload.sg_list);
blk_mq_end_request(rq, BLK_STS_OK);
}
void bsg_job_put(struct bsg_job *job)
{
kref_put(&job->kref, bsg_teardown_job);
}
EXPORT_SYMBOL_GPL(bsg_job_put);
int bsg_job_get(struct bsg_job *job)
{
return kref_get_unless_zero(&job->kref);
}
EXPORT_SYMBOL_GPL(bsg_job_get);
/**
* bsg_job_done - completion routine for bsg requests
* @job: bsg_job that is complete
* @result: job reply result
* @reply_payload_rcv_len: length of payload recvd
*
* The LLD should call this when the bsg job has completed.
*/
void bsg_job_done(struct bsg_job *job, int result,
unsigned int reply_payload_rcv_len)
{
job->result = result;
job->reply_payload_rcv_len = reply_payload_rcv_len;
blk_mq_complete_request(blk_mq_rq_from_pdu(job));
}
EXPORT_SYMBOL_GPL(bsg_job_done);
/**
* bsg_complete - softirq done routine for destroying the bsg requests
* @rq: BSG request that holds the job to be destroyed
*/
static void bsg_complete(struct request *rq)
{
struct bsg_job *job = blk_mq_rq_to_pdu(rq);
bsg_job_put(job);
}
static int 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;
}
/**
* bsg_prepare_job - create the bsg_job structure for the bsg request
* @dev: device that is being sent the bsg request
* @req: BSG request that needs a job structure
*/
static bool bsg_prepare_job(struct device *dev, struct request *req)
{
struct bsg_job *job = blk_mq_rq_to_pdu(req);
int ret;
job->timeout = req->timeout;
if (req->bio) {
ret = bsg_map_buffer(&job->request_payload, req);
if (ret)
goto failjob_rls_job;
}
if (job->bidi_rq) {
ret = bsg_map_buffer(&job->reply_payload, job->bidi_rq);
if (ret)
goto failjob_rls_rqst_payload;
}
job->dev = dev;
/* take a reference for the request */
get_device(job->dev);
kref_init(&job->kref);
return true;
failjob_rls_rqst_payload:
kfree(job->request_payload.sg_list);
failjob_rls_job:
job->result = -ENOMEM;
return false;
}
/**
* bsg_queue_rq - generic handler for bsg requests
* @hctx: hardware queue
* @bd: queue data
*
* On error the create_bsg_job function should return a -Exyz error value
* that will be set to ->result.
*
* Drivers/subsys should pass this to the queue init function.
*/
static blk_status_t bsg_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct request_queue *q = hctx->queue;
struct device *dev = q->queuedata;
struct request *req = bd->rq;
struct bsg_set *bset =
container_of(q->tag_set, struct bsg_set, tag_set);
blk_status_t sts = BLK_STS_IOERR;
int ret;
blk_mq_start_request(req);
if (!get_device(dev))
return BLK_STS_IOERR;
if (!bsg_prepare_job(dev, req))
goto out;
ret = bset->job_fn(blk_mq_rq_to_pdu(req));
if (!ret)
sts = BLK_STS_OK;
out:
put_device(dev);
return sts;
}
/* called right after the request is allocated for the request_queue */
static int bsg_init_rq(struct blk_mq_tag_set *set, struct request *req,
unsigned int hctx_idx, unsigned int numa_node)
{
struct bsg_job *job = blk_mq_rq_to_pdu(req);
job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL);
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);
void *reply = job->reply;
memset(job, 0, sizeof(*job));
job->reply = reply;
job->reply_len = SCSI_SENSE_BUFFERSIZE;
job->dd_data = job + 1;
}
static void bsg_exit_rq(struct blk_mq_tag_set *set, struct request *req,
unsigned int hctx_idx)
{
struct bsg_job *job = blk_mq_rq_to_pdu(req);
kfree(job->reply);
}
void bsg_remove_queue(struct request_queue *q)
{
if (q) {
struct bsg_set *bset =
container_of(q->tag_set, struct bsg_set, tag_set);
bsg_unregister_queue(q);
blk_cleanup_queue(q);
blk_mq_free_tag_set(&bset->tag_set);
kfree(bset);
}
}
EXPORT_SYMBOL_GPL(bsg_remove_queue);
static enum blk_eh_timer_return bsg_timeout(struct request *rq, bool reserved)
{
struct bsg_set *bset =
container_of(rq->q->tag_set, struct bsg_set, tag_set);
if (!bset->timeout_fn)
return BLK_EH_DONE;
return bset->timeout_fn(rq);
}
static const struct blk_mq_ops bsg_mq_ops = {
.queue_rq = bsg_queue_rq,
.init_request = bsg_init_rq,
.exit_request = bsg_exit_rq,
.initialize_rq_fn = bsg_initialize_rq,
.complete = bsg_complete,
.timeout = bsg_timeout,
};
/**
* bsg_setup_queue - Create and add the bsg hooks so we can receive requests
* @dev: device to attach bsg device to
* @name: device to give bsg device
* @job_fn: bsg job handler
* @timeout: timeout handler function pointer
* @dd_job_size: size of LLD data needed for each job
*/
struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
bsg_job_fn *job_fn, bsg_timeout_fn *timeout, int dd_job_size)
{
struct bsg_set *bset;
struct blk_mq_tag_set *set;
struct request_queue *q;
int ret = -ENOMEM;
bset = kzalloc(sizeof(*bset), GFP_KERNEL);
if (!bset)
return ERR_PTR(-ENOMEM);
bset->job_fn = job_fn;
bset->timeout_fn = timeout;
set = &bset->tag_set;
set->ops = &bsg_mq_ops,
set->nr_hw_queues = 1;
set->queue_depth = 128;
set->numa_node = NUMA_NO_NODE;
set->cmd_size = sizeof(struct bsg_job) + dd_job_size;
set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING;
if (blk_mq_alloc_tag_set(set))
goto out_tag_set;
q = blk_mq_init_queue(set);
if (IS_ERR(q)) {
ret = PTR_ERR(q);
goto out_queue;
}
q->queuedata = dev;
blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
ret = bsg_register_queue(q, dev, name, &bsg_transport_ops);
if (ret) {
printk(KERN_ERR "%s: bsg interface failed to "
"initialize - register queue\n", dev->kobj.name);
goto out_cleanup_queue;
}
return q;
out_cleanup_queue:
blk_cleanup_queue(q);
out_queue:
blk_mq_free_tag_set(set);
out_tag_set:
kfree(bset);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(bsg_setup_queue);