1 files changed, 415 insertions, 0 deletions
diff --git a/block/bsg-lib.c b/block/bsg-lib.c
new file mode 100644
index 000000000..330fede77
--- /dev/null
+++ b/block/bsg-lib.c
@@ -0,0 +1,415 @@
+// 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)
+{
+	struct request *rq = blk_mq_rq_from_pdu(job);
+
+	job->result = result;
+	job->reply_payload_rcv_len = reply_payload_rcv_len;
+	if (likely(!blk_should_fake_timeout(rq->q)))
+		blk_mq_complete_request(rq);
+}
+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 = kmalloc(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);