diff options
Diffstat (limited to 'block/bsg-lib.c')
| -rw-r--r-- | block/bsg-lib.c | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/block/bsg-lib.c b/block/bsg-lib.c new file mode 100644 index 000000000..f3501cdaf --- /dev/null +++ b/block/bsg-lib.c @@ -0,0 +1,343 @@ +/* + * 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); + + return PTR_ERR_OR_ZERO(job->request); +} + +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); |