From 17cb960f29c29ee07bf6848ada3265f4be55972e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 13 Mar 2018 17:28:41 +0100 Subject: bsg: split handling of SCSI CDBs vs transport requeues The current BSG design tries to shoe-horn the transport-specific passthrough commands into the overall framework for SCSI passthrough requests. This has a couple problems: - each passthrough queue has to set the QUEUE_FLAG_SCSI_PASSTHROUGH flag despite not dealing with SCSI commands at all. Because of that these queues could also incorrectly accept SCSI commands from in-kernel users or through the legacy SCSI_IOCTL_SEND_COMMAND ioctl. - the real SCSI bsg queues also incorrectly accept bsg requests of the BSG_SUB_PROTOCOL_SCSI_TRANSPORT type - the bsg transport code is almost unredable because it tries to reuse different SCSI concepts for its own purpose. This patch instead adds a new bsg_ops structure to handle the two cases differently, and thus solves all of the above problems. Another side effect is that the bsg-lib queues also don't need to embedd a struct scsi_request anymore. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Signed-off-by: Jens Axboe --- block/bsg-lib.c | 158 +++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 105 insertions(+), 53 deletions(-) (limited to 'block/bsg-lib.c') diff --git a/block/bsg-lib.c b/block/bsg-lib.c index f2c2d54a61b4..fc2e5ff2c4b9 100644 --- a/block/bsg-lib.c +++ b/block/bsg-lib.c @@ -27,6 +27,94 @@ #include #include #include +#include + +#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 @@ -68,27 +156,9 @@ EXPORT_SYMBOL_GPL(bsg_job_get); void bsg_job_done(struct bsg_job *job, int result, unsigned int reply_payload_rcv_len) { - struct request *req = blk_mq_rq_from_pdu(job); - struct request *rsp = req->next_rq; - int err; - - err = job->sreq.result = result; - if (err < 0) - /* we're only returning the result field in the reply */ - job->sreq.sense_len = sizeof(u32); - else - job->sreq.sense_len = job->reply_len; - /* we assume all request payload was transferred, residual == 0 */ - job->sreq.resid_len = 0; - - if (rsp) { - WARN_ON(reply_payload_rcv_len > scsi_req(rsp)->resid_len); - - /* set reply (bidi) residual */ - scsi_req(rsp)->resid_len -= - min(reply_payload_rcv_len, scsi_req(rsp)->resid_len); - } - blk_complete_request(req); + 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); @@ -113,7 +183,6 @@ static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) if (!buf->sg_list) return -ENOMEM; sg_init_table(buf->sg_list, req->nr_phys_segments); - scsi_req(req)->resid_len = blk_rq_bytes(req); buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list); buf->payload_len = blk_rq_bytes(req); return 0; @@ -124,16 +193,13 @@ static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) * @dev: device that is being sent the bsg request * @req: BSG request that needs a job structure */ -static int bsg_prepare_job(struct device *dev, struct request *req) +static bool bsg_prepare_job(struct device *dev, struct request *req) { struct request *rsp = req->next_rq; - struct scsi_request *rq = scsi_req(req); struct bsg_job *job = blk_mq_rq_to_pdu(req); int ret; job->timeout = req->timeout; - job->request = rq->cmd; - job->request_len = rq->cmd_len; if (req->bio) { ret = bsg_map_buffer(&job->request_payload, req); @@ -149,12 +215,13 @@ static int bsg_prepare_job(struct device *dev, struct request *req) /* take a reference for the request */ get_device(job->dev); kref_init(&job->kref); - return 0; + return true; failjob_rls_rqst_payload: kfree(job->request_payload.sg_list); failjob_rls_job: - return -ENOMEM; + job->result = -ENOMEM; + return false; } /** @@ -183,9 +250,7 @@ static void bsg_request_fn(struct request_queue *q) break; spin_unlock_irq(q->queue_lock); - ret = bsg_prepare_job(dev, req); - if (ret) { - scsi_req(req)->result = ret; + if (!bsg_prepare_job(dev, req)) { blk_end_request_all(req, BLK_STS_OK); spin_lock_irq(q->queue_lock); continue; @@ -202,46 +267,34 @@ static void bsg_request_fn(struct request_queue *q) 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); - struct scsi_request *sreq = &job->sreq; - - /* called right after the request is allocated for the request_queue */ - sreq->sense = kzalloc(SCSI_SENSE_BUFFERSIZE, gfp); - if (!sreq->sense) + 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); - struct scsi_request *sreq = &job->sreq; - void *sense = sreq->sense; - - /* called right before the request is given to the request_queue user */ + void *reply = job->reply; memset(job, 0, sizeof(*job)); - - scsi_req_init(sreq); - - sreq->sense = sense; - sreq->sense_len = SCSI_SENSE_BUFFERSIZE; - - job->reply = sense; - job->reply_len = sreq->sense_len; + 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); - struct scsi_request *sreq = &job->sreq; - kfree(sreq->sense); + kfree(job->reply); } /** @@ -275,11 +328,10 @@ struct request_queue *bsg_setup_queue(struct device *dev, const char *name, q->queuedata = dev; q->bsg_job_fn = job_fn; blk_queue_flag_set(QUEUE_FLAG_BIDI, q); - blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, 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, release); + ret = bsg_register_queue(q, dev, name, &bsg_transport_ops, release); if (ret) { printk(KERN_ERR "%s: bsg interface failed to " "initialize - register queue\n", dev->kobj.name); -- cgit v1.2.3