/* * BSG helper library * * Copyright (C) 2008 James Smart, Emulex Corporation * Copyright (C) 2011 Red Hat, Inc. All rights reserved. * Copyright (C) 2011 Mike Christie * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <linux/slab.h> #include <linux/blkdev.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)) 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 * @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_end_request_all(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_complete_request(blk_mq_rq_from_pdu(job)); } EXPORT_SYMBOL_GPL(bsg_job_done); /** * bsg_softirq_done - softirq done routine for destroying the bsg requests * @rq: BSG request that holds the job to be destroyed */ static void bsg_softirq_done(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 request *rsp = req->next_rq; 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 (rsp && rsp->bio) { ret = bsg_map_buffer(&job->reply_payload, rsp); 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_request_fn - generic handler for bsg requests * @q: request queue to manage * * 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 void bsg_request_fn(struct request_queue *q) __releases(q->queue_lock) __acquires(q->queue_lock) { struct device *dev = q->queuedata; struct request *req; int ret; if (!get_device(dev)) return; while (1) { req = blk_fetch_request(q); if (!req) break; spin_unlock_irq(q->queue_lock); if (!bsg_prepare_job(dev, req)) { blk_end_request_all(req, BLK_STS_OK); spin_lock_irq(q->queue_lock); continue; } ret = q->bsg_job_fn(blk_mq_rq_to_pdu(req)); spin_lock_irq(q->queue_lock); if (ret) break; } spin_unlock_irq(q->queue_lock); put_device(dev); 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); 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); 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 request_queue *q, struct request *req) { struct bsg_job *job = blk_mq_rq_to_pdu(req); kfree(job->reply); } /** * 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 * @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, int dd_job_size) { struct request_queue *q; int ret; q = blk_alloc_queue(GFP_KERNEL); if (!q) return ERR_PTR(-ENOMEM); q->cmd_size = sizeof(struct bsg_job) + dd_job_size; q->init_rq_fn = bsg_init_rq; q->exit_rq_fn = bsg_exit_rq; q->initialize_rq_fn = bsg_initialize_rq; q->request_fn = bsg_request_fn; ret = blk_init_allocated_queue(q); if (ret) goto out_cleanup_queue; q->queuedata = dev; q->bsg_job_fn = job_fn; blk_queue_flag_set(QUEUE_FLAG_BIDI, 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, &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); return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(bsg_setup_queue);