diff options
Diffstat (limited to 'block/bsg-lib.c')
-rw-r--r-- | block/bsg-lib.c | 411 |
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); |