xref: /openbmc/linux/drivers/target/tcm_fc/tfc_io.c (revision 0c6dfa75)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2010 Cisco Systems, Inc.
4  *
5  * Portions based on tcm_loop_fabric_scsi.c and libfc/fc_fcp.c
6  *
7  * Copyright (c) 2007 Intel Corporation. All rights reserved.
8  * Copyright (c) 2008 Red Hat, Inc.  All rights reserved.
9  * Copyright (c) 2008 Mike Christie
10  * Copyright (c) 2009 Rising Tide, Inc.
11  * Copyright (c) 2009 Linux-iSCSI.org
12  * Copyright (c) 2009 Nicholas A. Bellinger <nab@linux-iscsi.org>
13  */
14 
15 /* XXX TBD some includes may be extraneous */
16 
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/utsname.h>
20 #include <linux/init.h>
21 #include <linux/slab.h>
22 #include <linux/kthread.h>
23 #include <linux/types.h>
24 #include <linux/string.h>
25 #include <linux/configfs.h>
26 #include <linux/ctype.h>
27 #include <linux/hash.h>
28 #include <linux/ratelimit.h>
29 #include <asm/unaligned.h>
30 #include <scsi/libfc.h>
31 
32 #include <target/target_core_base.h>
33 #include <target/target_core_fabric.h>
34 
35 #include "tcm_fc.h"
36 
37 /*
38  * Deliver read data back to initiator.
39  * XXX TBD handle resource problems later.
40  */
41 int ft_queue_data_in(struct se_cmd *se_cmd)
42 {
43 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
44 	struct fc_frame *fp = NULL;
45 	struct fc_exch *ep;
46 	struct fc_lport *lport;
47 	struct scatterlist *sg = NULL;
48 	size_t remaining;
49 	u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
50 	u32 mem_off = 0;
51 	u32 fh_off = 0;
52 	u32 frame_off = 0;
53 	size_t frame_len = 0;
54 	size_t mem_len = 0;
55 	size_t tlen;
56 	size_t off_in_page;
57 	struct page *page = NULL;
58 	int use_sg;
59 	int error;
60 	void *page_addr;
61 	void *from;
62 	void *to = NULL;
63 
64 	if (cmd->aborted)
65 		return 0;
66 
67 	if (se_cmd->scsi_status == SAM_STAT_TASK_SET_FULL)
68 		goto queue_status;
69 
70 	ep = fc_seq_exch(cmd->seq);
71 	lport = ep->lp;
72 	cmd->seq = fc_seq_start_next(cmd->seq);
73 
74 	remaining = se_cmd->data_length;
75 
76 	/*
77 	 * Setup to use first mem list entry, unless no data.
78 	 */
79 	BUG_ON(remaining && !se_cmd->t_data_sg);
80 	if (remaining) {
81 		sg = se_cmd->t_data_sg;
82 		mem_len = sg->length;
83 		mem_off = sg->offset;
84 		page = sg_page(sg);
85 	}
86 
87 	/* no scatter/gather in skb for odd word length due to fc_seq_send() */
88 	use_sg = !(remaining % 4);
89 
90 	while (remaining) {
91 		struct fc_seq *seq = cmd->seq;
92 
93 		if (!seq) {
94 			pr_debug("%s: Command aborted, xid 0x%x\n",
95 				 __func__, ep->xid);
96 			break;
97 		}
98 		if (!mem_len) {
99 			sg = sg_next(sg);
100 			mem_len = min((size_t)sg->length, remaining);
101 			mem_off = sg->offset;
102 			page = sg_page(sg);
103 		}
104 		if (!frame_len) {
105 			/*
106 			 * If lport's has capability of Large Send Offload LSO)
107 			 * , then allow 'frame_len' to be as big as 'lso_max'
108 			 * if indicated transfer length is >= lport->lso_max
109 			 */
110 			frame_len = (lport->seq_offload) ? lport->lso_max :
111 							  cmd->sess->max_frame;
112 			frame_len = min(frame_len, remaining);
113 			fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
114 			if (!fp)
115 				return -ENOMEM;
116 			to = fc_frame_payload_get(fp, 0);
117 			fh_off = frame_off;
118 			frame_off += frame_len;
119 			/*
120 			 * Setup the frame's max payload which is used by base
121 			 * driver to indicate HW about max frame size, so that
122 			 * HW can do fragmentation appropriately based on
123 			 * "gso_max_size" of underline netdev.
124 			 */
125 			fr_max_payload(fp) = cmd->sess->max_frame;
126 		}
127 		tlen = min(mem_len, frame_len);
128 
129 		if (use_sg) {
130 			off_in_page = mem_off;
131 			BUG_ON(!page);
132 			get_page(page);
133 			skb_fill_page_desc(fp_skb(fp),
134 					   skb_shinfo(fp_skb(fp))->nr_frags,
135 					   page, off_in_page, tlen);
136 			fr_len(fp) += tlen;
137 			fp_skb(fp)->data_len += tlen;
138 			fp_skb(fp)->truesize += page_size(page);
139 		} else {
140 			BUG_ON(!page);
141 			from = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
142 			page_addr = from;
143 			from += offset_in_page(mem_off);
144 			tlen = min(tlen, (size_t)(PAGE_SIZE -
145 						offset_in_page(mem_off)));
146 			memcpy(to, from, tlen);
147 			kunmap_atomic(page_addr);
148 			to += tlen;
149 		}
150 
151 		mem_off += tlen;
152 		mem_len -= tlen;
153 		frame_len -= tlen;
154 		remaining -= tlen;
155 
156 		if (frame_len &&
157 		    (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
158 			continue;
159 		if (!remaining)
160 			f_ctl |= FC_FC_END_SEQ;
161 		fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
162 			       FC_TYPE_FCP, f_ctl, fh_off);
163 		error = fc_seq_send(lport, seq, fp);
164 		if (error) {
165 			pr_info_ratelimited("%s: Failed to send frame %p, "
166 						"xid <0x%x>, remaining %zu, "
167 						"lso_max <0x%x>\n",
168 						__func__, fp, ep->xid,
169 						remaining, lport->lso_max);
170 			/*
171 			 * Go ahead and set TASK_SET_FULL status ignoring the
172 			 * rest of the DataIN, and immediately attempt to
173 			 * send the response via ft_queue_status() in order
174 			 * to notify the initiator that it should reduce it's
175 			 * per LUN queue_depth.
176 			 */
177 			se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
178 			break;
179 		}
180 	}
181 queue_status:
182 	return ft_queue_status(se_cmd);
183 }
184 
185 static void ft_execute_work(struct work_struct *work)
186 {
187 	struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);
188 
189 	target_execute_cmd(&cmd->se_cmd);
190 }
191 
192 /*
193  * Receive write data frame.
194  */
195 void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
196 {
197 	struct se_cmd *se_cmd = &cmd->se_cmd;
198 	struct fc_seq *seq = cmd->seq;
199 	struct fc_exch *ep;
200 	struct fc_lport *lport;
201 	struct fc_frame_header *fh;
202 	struct scatterlist *sg = NULL;
203 	u32 mem_off = 0;
204 	u32 rel_off;
205 	size_t frame_len;
206 	size_t mem_len = 0;
207 	size_t tlen;
208 	struct page *page = NULL;
209 	void *page_addr;
210 	void *from;
211 	void *to;
212 	u32 f_ctl;
213 	void *buf;
214 
215 	fh = fc_frame_header_get(fp);
216 	if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
217 		goto drop;
218 
219 	f_ctl = ntoh24(fh->fh_f_ctl);
220 	ep = fc_seq_exch(seq);
221 	lport = ep->lp;
222 	if (cmd->was_ddp_setup) {
223 		BUG_ON(!lport);
224 		/*
225 		 * Since DDP (Large Rx offload) was setup for this request,
226 		 * payload is expected to be copied directly to user buffers.
227 		 */
228 		buf = fc_frame_payload_get(fp, 1);
229 		if (buf)
230 			pr_err("%s: xid 0x%x, f_ctl 0x%x, cmd->sg %p, "
231 				"cmd->sg_cnt 0x%x. DDP was setup"
232 				" hence not expected to receive frame with "
233 				"payload, Frame will be dropped if"
234 				"'Sequence Initiative' bit in f_ctl is"
235 				"not set\n", __func__, ep->xid, f_ctl,
236 				se_cmd->t_data_sg, se_cmd->t_data_nents);
237 		/*
238 		 * Invalidate HW DDP context if it was setup for respective
239 		 * command. Invalidation of HW DDP context is requited in both
240 		 * situation (success and error).
241 		 */
242 		ft_invl_hw_context(cmd);
243 
244 		/*
245 		 * If "Sequence Initiative (TSI)" bit set in f_ctl, means last
246 		 * write data frame is received successfully where payload is
247 		 * posted directly to user buffer and only the last frame's
248 		 * header is posted in receive queue.
249 		 *
250 		 * If "Sequence Initiative (TSI)" bit is not set, means error
251 		 * condition w.r.t. DDP, hence drop the packet and let explict
252 		 * ABORTS from other end of exchange timer trigger the recovery.
253 		 */
254 		if (f_ctl & FC_FC_SEQ_INIT)
255 			goto last_frame;
256 		else
257 			goto drop;
258 	}
259 
260 	rel_off = ntohl(fh->fh_parm_offset);
261 	frame_len = fr_len(fp);
262 	if (frame_len <= sizeof(*fh))
263 		goto drop;
264 	frame_len -= sizeof(*fh);
265 	from = fc_frame_payload_get(fp, 0);
266 	if (rel_off >= se_cmd->data_length)
267 		goto drop;
268 	if (frame_len + rel_off > se_cmd->data_length)
269 		frame_len = se_cmd->data_length - rel_off;
270 
271 	/*
272 	 * Setup to use first mem list entry, unless no data.
273 	 */
274 	BUG_ON(frame_len && !se_cmd->t_data_sg);
275 	if (frame_len) {
276 		sg = se_cmd->t_data_sg;
277 		mem_len = sg->length;
278 		mem_off = sg->offset;
279 		page = sg_page(sg);
280 	}
281 
282 	while (frame_len) {
283 		if (!mem_len) {
284 			sg = sg_next(sg);
285 			mem_len = sg->length;
286 			mem_off = sg->offset;
287 			page = sg_page(sg);
288 		}
289 		if (rel_off >= mem_len) {
290 			rel_off -= mem_len;
291 			mem_len = 0;
292 			continue;
293 		}
294 		mem_off += rel_off;
295 		mem_len -= rel_off;
296 		rel_off = 0;
297 
298 		tlen = min(mem_len, frame_len);
299 
300 		to = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
301 		page_addr = to;
302 		to += offset_in_page(mem_off);
303 		tlen = min(tlen, (size_t)(PAGE_SIZE -
304 					  offset_in_page(mem_off)));
305 		memcpy(to, from, tlen);
306 		kunmap_atomic(page_addr);
307 
308 		from += tlen;
309 		frame_len -= tlen;
310 		mem_off += tlen;
311 		mem_len -= tlen;
312 		cmd->write_data_len += tlen;
313 	}
314 last_frame:
315 	if (cmd->write_data_len == se_cmd->data_length) {
316 		INIT_WORK(&cmd->work, ft_execute_work);
317 		queue_work(cmd->sess->tport->tpg->workqueue, &cmd->work);
318 	}
319 drop:
320 	fc_frame_free(fp);
321 }
322 
323 /*
324  * Handle and cleanup any HW specific resources if
325  * received ABORTS, errors, timeouts.
326  */
327 void ft_invl_hw_context(struct ft_cmd *cmd)
328 {
329 	struct fc_seq *seq;
330 	struct fc_exch *ep = NULL;
331 	struct fc_lport *lport = NULL;
332 
333 	BUG_ON(!cmd);
334 	seq = cmd->seq;
335 
336 	/* Cleanup the DDP context in HW if DDP was setup */
337 	if (cmd->was_ddp_setup && seq) {
338 		ep = fc_seq_exch(seq);
339 		if (ep) {
340 			lport = ep->lp;
341 			if (lport && (ep->xid <= lport->lro_xid)) {
342 				/*
343 				 * "ddp_done" trigger invalidation of HW
344 				 * specific DDP context
345 				 */
346 				cmd->write_data_len = lport->tt.ddp_done(lport,
347 								      ep->xid);
348 
349 				/*
350 				 * Resetting same variable to indicate HW's
351 				 * DDP context has been invalidated to avoid
352 				 * re_invalidation of same context (context is
353 				 * identified using ep->xid)
354 				 */
355 				cmd->was_ddp_setup = 0;
356 			}
357 		}
358 	}
359 }
360