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-rw-r--r--block/bsg-lib.c411
1 files changed, 411 insertions, 0 deletions
diff --git a/block/bsg-lib.c b/block/bsg-lib.c
new file mode 100644
index 0000000000..b3acdbdb6e
--- /dev/null
+++ b/block/bsg-lib.c
@@ -0,0 +1,411 @@
+// 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/bsg.h>
+#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;
+ struct bsg_device *bd;
+ bsg_job_fn *job_fn;
+ bsg_timeout_fn *timeout_fn;
+};
+
+static int bsg_transport_sg_io_fn(struct request_queue *q, struct sg_io_v4 *hdr,
+ bool open_for_write, unsigned int timeout)
+{
+ struct bsg_job *job;
+ struct request *rq;
+ struct bio *bio;
+ void *reply;
+ int ret;
+
+ if (hdr->protocol != BSG_PROTOCOL_SCSI ||
+ hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT)
+ return -EINVAL;
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ rq = blk_mq_alloc_request(q, hdr->dout_xfer_len ?
+ REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
+ if (IS_ERR(rq))
+ return PTR_ERR(rq);
+ rq->timeout = timeout;
+
+ job = blk_mq_rq_to_pdu(rq);
+ reply = job->reply;
+ memset(job, 0, sizeof(*job));
+ job->reply = reply;
+ job->reply_len = SCSI_SENSE_BUFFERSIZE;
+ job->dd_data = job + 1;
+
+ job->request_len = hdr->request_len;
+ job->request = memdup_user(uptr64(hdr->request), hdr->request_len);
+ if (IS_ERR(job->request)) {
+ ret = PTR_ERR(job->request);
+ goto out_free_rq;
+ }
+
+ if (hdr->dout_xfer_len && hdr->din_xfer_len) {
+ job->bidi_rq = blk_mq_alloc_request(rq->q, REQ_OP_DRV_IN, 0);
+ if (IS_ERR(job->bidi_rq)) {
+ ret = PTR_ERR(job->bidi_rq);
+ goto out_free_job_request;
+ }
+
+ 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;
+ }
+
+ ret = 0;
+ if (hdr->dout_xfer_len) {
+ ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->dout_xferp),
+ hdr->dout_xfer_len, GFP_KERNEL);
+ } else if (hdr->din_xfer_len) {
+ ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->din_xferp),
+ hdr->din_xfer_len, GFP_KERNEL);
+ }
+
+ if (ret)
+ goto out_unmap_bidi_rq;
+
+ bio = rq->bio;
+ blk_execute_rq(rq, !(hdr->flags & BSG_FLAG_Q_AT_TAIL));
+
+ /*
+ * 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 = 0;
+ 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;
+ }
+
+ blk_rq_unmap_user(bio);
+out_unmap_bidi_rq:
+ if (job->bidi_rq)
+ blk_rq_unmap_user(job->bidi_bio);
+out_free_bidi_rq:
+ if (job->bidi_rq)
+ blk_mq_free_request(job->bidi_rq);
+out_free_job_request:
+ kfree(job->request);
+out_free_rq:
+ blk_mq_free_request(rq);
+ return ret;
+}
+
+/**
+ * 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;
+}
+
+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(bset->bd);
+ blk_mq_destroy_queue(q);
+ blk_put_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)
+{
+ 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,
+ .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);
+
+ bset->bd = bsg_register_queue(q, dev, name, bsg_transport_sg_io_fn);
+ if (IS_ERR(bset->bd)) {
+ ret = PTR_ERR(bset->bd);
+ goto out_cleanup_queue;
+ }
+
+ return q;
+out_cleanup_queue:
+ blk_mq_destroy_queue(q);
+ blk_put_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);