bsg-lib.c 9.9 KB

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  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * BSG helper library
  4. *
  5. * Copyright (C) 2008 James Smart, Emulex Corporation
  6. * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
  7. * Copyright (C) 2011 Mike Christie
  8. */
  9. #include <linux/slab.h>
  10. #include <linux/blk-mq.h>
  11. #include <linux/delay.h>
  12. #include <linux/scatterlist.h>
  13. #include <linux/bsg-lib.h>
  14. #include <linux/export.h>
  15. #include <scsi/scsi_cmnd.h>
  16. #include <scsi/sg.h>
  17. #define uptr64(val) ((void __user *)(uintptr_t)(val))
  18. struct bsg_set {
  19. struct blk_mq_tag_set tag_set;
  20. bsg_job_fn *job_fn;
  21. bsg_timeout_fn *timeout_fn;
  22. };
  23. static int bsg_transport_check_proto(struct sg_io_v4 *hdr)
  24. {
  25. if (hdr->protocol != BSG_PROTOCOL_SCSI ||
  26. hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT)
  27. return -EINVAL;
  28. if (!capable(CAP_SYS_RAWIO))
  29. return -EPERM;
  30. return 0;
  31. }
  32. static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
  33. fmode_t mode)
  34. {
  35. struct bsg_job *job = blk_mq_rq_to_pdu(rq);
  36. int ret;
  37. job->request_len = hdr->request_len;
  38. job->request = memdup_user(uptr64(hdr->request), hdr->request_len);
  39. if (IS_ERR(job->request))
  40. return PTR_ERR(job->request);
  41. if (hdr->dout_xfer_len && hdr->din_xfer_len) {
  42. job->bidi_rq = blk_get_request(rq->q, REQ_OP_SCSI_IN, 0);
  43. if (IS_ERR(job->bidi_rq)) {
  44. ret = PTR_ERR(job->bidi_rq);
  45. goto out;
  46. }
  47. ret = blk_rq_map_user(rq->q, job->bidi_rq, NULL,
  48. uptr64(hdr->din_xferp), hdr->din_xfer_len,
  49. GFP_KERNEL);
  50. if (ret)
  51. goto out_free_bidi_rq;
  52. job->bidi_bio = job->bidi_rq->bio;
  53. } else {
  54. job->bidi_rq = NULL;
  55. job->bidi_bio = NULL;
  56. }
  57. return 0;
  58. out_free_bidi_rq:
  59. if (job->bidi_rq)
  60. blk_put_request(job->bidi_rq);
  61. out:
  62. kfree(job->request);
  63. return ret;
  64. }
  65. static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
  66. {
  67. struct bsg_job *job = blk_mq_rq_to_pdu(rq);
  68. int ret = 0;
  69. /*
  70. * The assignments below don't make much sense, but are kept for
  71. * bug by bug backwards compatibility:
  72. */
  73. hdr->device_status = job->result & 0xff;
  74. hdr->transport_status = host_byte(job->result);
  75. hdr->driver_status = driver_byte(job->result);
  76. hdr->info = 0;
  77. if (hdr->device_status || hdr->transport_status || hdr->driver_status)
  78. hdr->info |= SG_INFO_CHECK;
  79. hdr->response_len = 0;
  80. if (job->result < 0) {
  81. /* we're only returning the result field in the reply */
  82. job->reply_len = sizeof(u32);
  83. ret = job->result;
  84. }
  85. if (job->reply_len && hdr->response) {
  86. int len = min(hdr->max_response_len, job->reply_len);
  87. if (copy_to_user(uptr64(hdr->response), job->reply, len))
  88. ret = -EFAULT;
  89. else
  90. hdr->response_len = len;
  91. }
  92. /* we assume all request payload was transferred, residual == 0 */
  93. hdr->dout_resid = 0;
  94. if (job->bidi_rq) {
  95. unsigned int rsp_len = job->reply_payload.payload_len;
  96. if (WARN_ON(job->reply_payload_rcv_len > rsp_len))
  97. hdr->din_resid = 0;
  98. else
  99. hdr->din_resid = rsp_len - job->reply_payload_rcv_len;
  100. } else {
  101. hdr->din_resid = 0;
  102. }
  103. return ret;
  104. }
  105. static void bsg_transport_free_rq(struct request *rq)
  106. {
  107. struct bsg_job *job = blk_mq_rq_to_pdu(rq);
  108. if (job->bidi_rq) {
  109. blk_rq_unmap_user(job->bidi_bio);
  110. blk_put_request(job->bidi_rq);
  111. }
  112. kfree(job->request);
  113. }
  114. static const struct bsg_ops bsg_transport_ops = {
  115. .check_proto = bsg_transport_check_proto,
  116. .fill_hdr = bsg_transport_fill_hdr,
  117. .complete_rq = bsg_transport_complete_rq,
  118. .free_rq = bsg_transport_free_rq,
  119. };
  120. /**
  121. * bsg_teardown_job - routine to teardown a bsg job
  122. * @kref: kref inside bsg_job that is to be torn down
  123. */
  124. static void bsg_teardown_job(struct kref *kref)
  125. {
  126. struct bsg_job *job = container_of(kref, struct bsg_job, kref);
  127. struct request *rq = blk_mq_rq_from_pdu(job);
  128. put_device(job->dev); /* release reference for the request */
  129. kfree(job->request_payload.sg_list);
  130. kfree(job->reply_payload.sg_list);
  131. blk_mq_end_request(rq, BLK_STS_OK);
  132. }
  133. void bsg_job_put(struct bsg_job *job)
  134. {
  135. kref_put(&job->kref, bsg_teardown_job);
  136. }
  137. EXPORT_SYMBOL_GPL(bsg_job_put);
  138. int bsg_job_get(struct bsg_job *job)
  139. {
  140. return kref_get_unless_zero(&job->kref);
  141. }
  142. EXPORT_SYMBOL_GPL(bsg_job_get);
  143. /**
  144. * bsg_job_done - completion routine for bsg requests
  145. * @job: bsg_job that is complete
  146. * @result: job reply result
  147. * @reply_payload_rcv_len: length of payload recvd
  148. *
  149. * The LLD should call this when the bsg job has completed.
  150. */
  151. void bsg_job_done(struct bsg_job *job, int result,
  152. unsigned int reply_payload_rcv_len)
  153. {
  154. struct request *rq = blk_mq_rq_from_pdu(job);
  155. job->result = result;
  156. job->reply_payload_rcv_len = reply_payload_rcv_len;
  157. if (likely(!blk_should_fake_timeout(rq->q)))
  158. blk_mq_complete_request(rq);
  159. }
  160. EXPORT_SYMBOL_GPL(bsg_job_done);
  161. /**
  162. * bsg_complete - softirq done routine for destroying the bsg requests
  163. * @rq: BSG request that holds the job to be destroyed
  164. */
  165. static void bsg_complete(struct request *rq)
  166. {
  167. struct bsg_job *job = blk_mq_rq_to_pdu(rq);
  168. bsg_job_put(job);
  169. }
  170. static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
  171. {
  172. size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
  173. BUG_ON(!req->nr_phys_segments);
  174. buf->sg_list = kmalloc(sz, GFP_KERNEL);
  175. if (!buf->sg_list)
  176. return -ENOMEM;
  177. sg_init_table(buf->sg_list, req->nr_phys_segments);
  178. buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
  179. buf->payload_len = blk_rq_bytes(req);
  180. return 0;
  181. }
  182. /**
  183. * bsg_prepare_job - create the bsg_job structure for the bsg request
  184. * @dev: device that is being sent the bsg request
  185. * @req: BSG request that needs a job structure
  186. */
  187. static bool bsg_prepare_job(struct device *dev, struct request *req)
  188. {
  189. struct bsg_job *job = blk_mq_rq_to_pdu(req);
  190. int ret;
  191. job->timeout = req->timeout;
  192. if (req->bio) {
  193. ret = bsg_map_buffer(&job->request_payload, req);
  194. if (ret)
  195. goto failjob_rls_job;
  196. }
  197. if (job->bidi_rq) {
  198. ret = bsg_map_buffer(&job->reply_payload, job->bidi_rq);
  199. if (ret)
  200. goto failjob_rls_rqst_payload;
  201. }
  202. job->dev = dev;
  203. /* take a reference for the request */
  204. get_device(job->dev);
  205. kref_init(&job->kref);
  206. return true;
  207. failjob_rls_rqst_payload:
  208. kfree(job->request_payload.sg_list);
  209. failjob_rls_job:
  210. job->result = -ENOMEM;
  211. return false;
  212. }
  213. /**
  214. * bsg_queue_rq - generic handler for bsg requests
  215. * @hctx: hardware queue
  216. * @bd: queue data
  217. *
  218. * On error the create_bsg_job function should return a -Exyz error value
  219. * that will be set to ->result.
  220. *
  221. * Drivers/subsys should pass this to the queue init function.
  222. */
  223. static blk_status_t bsg_queue_rq(struct blk_mq_hw_ctx *hctx,
  224. const struct blk_mq_queue_data *bd)
  225. {
  226. struct request_queue *q = hctx->queue;
  227. struct device *dev = q->queuedata;
  228. struct request *req = bd->rq;
  229. struct bsg_set *bset =
  230. container_of(q->tag_set, struct bsg_set, tag_set);
  231. blk_status_t sts = BLK_STS_IOERR;
  232. int ret;
  233. blk_mq_start_request(req);
  234. if (!get_device(dev))
  235. return BLK_STS_IOERR;
  236. if (!bsg_prepare_job(dev, req))
  237. goto out;
  238. ret = bset->job_fn(blk_mq_rq_to_pdu(req));
  239. if (!ret)
  240. sts = BLK_STS_OK;
  241. out:
  242. put_device(dev);
  243. return sts;
  244. }
  245. /* called right after the request is allocated for the request_queue */
  246. static int bsg_init_rq(struct blk_mq_tag_set *set, struct request *req,
  247. unsigned int hctx_idx, unsigned int numa_node)
  248. {
  249. struct bsg_job *job = blk_mq_rq_to_pdu(req);
  250. job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL);
  251. if (!job->reply)
  252. return -ENOMEM;
  253. return 0;
  254. }
  255. /* called right before the request is given to the request_queue user */
  256. static void bsg_initialize_rq(struct request *req)
  257. {
  258. struct bsg_job *job = blk_mq_rq_to_pdu(req);
  259. void *reply = job->reply;
  260. memset(job, 0, sizeof(*job));
  261. job->reply = reply;
  262. job->reply_len = SCSI_SENSE_BUFFERSIZE;
  263. job->dd_data = job + 1;
  264. }
  265. static void bsg_exit_rq(struct blk_mq_tag_set *set, struct request *req,
  266. unsigned int hctx_idx)
  267. {
  268. struct bsg_job *job = blk_mq_rq_to_pdu(req);
  269. kfree(job->reply);
  270. }
  271. void bsg_remove_queue(struct request_queue *q)
  272. {
  273. if (q) {
  274. struct bsg_set *bset =
  275. container_of(q->tag_set, struct bsg_set, tag_set);
  276. bsg_unregister_queue(q);
  277. blk_cleanup_queue(q);
  278. blk_mq_free_tag_set(&bset->tag_set);
  279. kfree(bset);
  280. }
  281. }
  282. EXPORT_SYMBOL_GPL(bsg_remove_queue);
  283. static enum blk_eh_timer_return bsg_timeout(struct request *rq, bool reserved)
  284. {
  285. struct bsg_set *bset =
  286. container_of(rq->q->tag_set, struct bsg_set, tag_set);
  287. if (!bset->timeout_fn)
  288. return BLK_EH_DONE;
  289. return bset->timeout_fn(rq);
  290. }
  291. static const struct blk_mq_ops bsg_mq_ops = {
  292. .queue_rq = bsg_queue_rq,
  293. .init_request = bsg_init_rq,
  294. .exit_request = bsg_exit_rq,
  295. .initialize_rq_fn = bsg_initialize_rq,
  296. .complete = bsg_complete,
  297. .timeout = bsg_timeout,
  298. };
  299. /**
  300. * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
  301. * @dev: device to attach bsg device to
  302. * @name: device to give bsg device
  303. * @job_fn: bsg job handler
  304. * @timeout: timeout handler function pointer
  305. * @dd_job_size: size of LLD data needed for each job
  306. */
  307. struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
  308. bsg_job_fn *job_fn, bsg_timeout_fn *timeout, int dd_job_size)
  309. {
  310. struct bsg_set *bset;
  311. struct blk_mq_tag_set *set;
  312. struct request_queue *q;
  313. int ret = -ENOMEM;
  314. bset = kzalloc(sizeof(*bset), GFP_KERNEL);
  315. if (!bset)
  316. return ERR_PTR(-ENOMEM);
  317. bset->job_fn = job_fn;
  318. bset->timeout_fn = timeout;
  319. set = &bset->tag_set;
  320. set->ops = &bsg_mq_ops;
  321. set->nr_hw_queues = 1;
  322. set->queue_depth = 128;
  323. set->numa_node = NUMA_NO_NODE;
  324. set->cmd_size = sizeof(struct bsg_job) + dd_job_size;
  325. set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING;
  326. if (blk_mq_alloc_tag_set(set))
  327. goto out_tag_set;
  328. q = blk_mq_init_queue(set);
  329. if (IS_ERR(q)) {
  330. ret = PTR_ERR(q);
  331. goto out_queue;
  332. }
  333. q->queuedata = dev;
  334. blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
  335. ret = bsg_register_queue(q, dev, name, &bsg_transport_ops);
  336. if (ret) {
  337. printk(KERN_ERR "%s: bsg interface failed to "
  338. "initialize - register queue\n", dev->kobj.name);
  339. goto out_cleanup_queue;
  340. }
  341. return q;
  342. out_cleanup_queue:
  343. blk_cleanup_queue(q);
  344. out_queue:
  345. blk_mq_free_tag_set(set);
  346. out_tag_set:
  347. kfree(bset);
  348. return ERR_PTR(ret);
  349. }
  350. EXPORT_SYMBOL_GPL(bsg_setup_queue);