1/*
2 * Copyright (c) 2010 Cisco Systems, Inc.
3 *
4 * Portions based on tcm_loop_fabric_scsi.c and libfc/fc_fcp.c
5 *
6 * Copyright (c) 2007 Intel Corporation. All rights reserved.
7 * Copyright (c) 2008 Red Hat, Inc.  All rights reserved.
8 * Copyright (c) 2008 Mike Christie
9 * Copyright (c) 2009 Rising Tide, Inc.
10 * Copyright (c) 2009 Linux-iSCSI.org
11 * Copyright (c) 2009 Nicholas A. Bellinger <nab@linux-iscsi.org>
12 *
13 * This program is free software; you can redistribute it and/or modify it
14 * under the terms and conditions of the GNU General Public License,
15 * version 2, as published by the Free Software Foundation.
16 *
17 * This program is distributed in the hope it will be useful, but WITHOUT
18 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
20 * more details.
21 *
22 * You should have received a copy of the GNU General Public License along with
23 * this program; if not, write to the Free Software Foundation, Inc.,
24 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
25 */
26
27/* XXX TBD some includes may be extraneous */
28
29#include <linux/module.h>
30#include <linux/moduleparam.h>
31#include <linux/utsname.h>
32#include <linux/init.h>
33#include <linux/slab.h>
34#include <linux/kthread.h>
35#include <linux/types.h>
36#include <linux/string.h>
37#include <linux/configfs.h>
38#include <linux/ctype.h>
39#include <linux/hash.h>
40#include <linux/ratelimit.h>
41#include <asm/unaligned.h>
42#include <scsi/libfc.h>
43#include <scsi/fc_encode.h>
44
45#include <target/target_core_base.h>
46#include <target/target_core_fabric.h>
47
48#include "tcm_fc.h"
49
50/*
51 * Deliver read data back to initiator.
52 * XXX TBD handle resource problems later.
53 */
54int ft_queue_data_in(struct se_cmd *se_cmd)
55{
56	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
57	struct fc_frame *fp = NULL;
58	struct fc_exch *ep;
59	struct fc_lport *lport;
60	struct scatterlist *sg = NULL;
61	size_t remaining;
62	u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
63	u32 mem_off = 0;
64	u32 fh_off = 0;
65	u32 frame_off = 0;
66	size_t frame_len = 0;
67	size_t mem_len = 0;
68	size_t tlen;
69	size_t off_in_page;
70	struct page *page = NULL;
71	int use_sg;
72	int error;
73	void *page_addr;
74	void *from;
75	void *to = NULL;
76
77	if (cmd->aborted)
78		return 0;
79
80	if (se_cmd->scsi_status == SAM_STAT_TASK_SET_FULL)
81		goto queue_status;
82
83	ep = fc_seq_exch(cmd->seq);
84	lport = ep->lp;
85	cmd->seq = lport->tt.seq_start_next(cmd->seq);
86
87	remaining = se_cmd->data_length;
88
89	/*
90	 * Setup to use first mem list entry, unless no data.
91	 */
92	BUG_ON(remaining && !se_cmd->t_data_sg);
93	if (remaining) {
94		sg = se_cmd->t_data_sg;
95		mem_len = sg->length;
96		mem_off = sg->offset;
97		page = sg_page(sg);
98	}
99
100	/* no scatter/gather in skb for odd word length due to fc_seq_send() */
101	use_sg = !(remaining % 4);
102
103	while (remaining) {
104		struct fc_seq *seq = cmd->seq;
105
106		if (!seq) {
107			pr_debug("%s: Command aborted, xid 0x%x\n",
108				 __func__, ep->xid);
109			break;
110		}
111		if (!mem_len) {
112			sg = sg_next(sg);
113			mem_len = min((size_t)sg->length, remaining);
114			mem_off = sg->offset;
115			page = sg_page(sg);
116		}
117		if (!frame_len) {
118			/*
119			 * If lport's has capability of Large Send Offload LSO)
120			 * , then allow 'frame_len' to be as big as 'lso_max'
121			 * if indicated transfer length is >= lport->lso_max
122			 */
123			frame_len = (lport->seq_offload) ? lport->lso_max :
124							  cmd->sess->max_frame;
125			frame_len = min(frame_len, remaining);
126			fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
127			if (!fp)
128				return -ENOMEM;
129			to = fc_frame_payload_get(fp, 0);
130			fh_off = frame_off;
131			frame_off += frame_len;
132			/*
133			 * Setup the frame's max payload which is used by base
134			 * driver to indicate HW about max frame size, so that
135			 * HW can do fragmentation appropriately based on
136			 * "gso_max_size" of underline netdev.
137			 */
138			fr_max_payload(fp) = cmd->sess->max_frame;
139		}
140		tlen = min(mem_len, frame_len);
141
142		if (use_sg) {
143			off_in_page = mem_off;
144			BUG_ON(!page);
145			get_page(page);
146			skb_fill_page_desc(fp_skb(fp),
147					   skb_shinfo(fp_skb(fp))->nr_frags,
148					   page, off_in_page, tlen);
149			fr_len(fp) += tlen;
150			fp_skb(fp)->data_len += tlen;
151			fp_skb(fp)->truesize +=
152					PAGE_SIZE << compound_order(page);
153		} else {
154			BUG_ON(!page);
155			from = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
156			page_addr = from;
157			from += mem_off & ~PAGE_MASK;
158			tlen = min(tlen, (size_t)(PAGE_SIZE -
159						(mem_off & ~PAGE_MASK)));
160			memcpy(to, from, tlen);
161			kunmap_atomic(page_addr);
162			to += tlen;
163		}
164
165		mem_off += tlen;
166		mem_len -= tlen;
167		frame_len -= tlen;
168		remaining -= tlen;
169
170		if (frame_len &&
171		    (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
172			continue;
173		if (!remaining)
174			f_ctl |= FC_FC_END_SEQ;
175		fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
176			       FC_TYPE_FCP, f_ctl, fh_off);
177		error = lport->tt.seq_send(lport, seq, fp);
178		if (error) {
179			pr_info_ratelimited("%s: Failed to send frame %p, "
180						"xid <0x%x>, remaining %zu, "
181						"lso_max <0x%x>\n",
182						__func__, fp, ep->xid,
183						remaining, lport->lso_max);
184			/*
185			 * Go ahead and set TASK_SET_FULL status ignoring the
186			 * rest of the DataIN, and immediately attempt to
187			 * send the response via ft_queue_status() in order
188			 * to notify the initiator that it should reduce it's
189			 * per LUN queue_depth.
190			 */
191			se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
192			break;
193		}
194	}
195queue_status:
196	return ft_queue_status(se_cmd);
197}
198
199static void ft_execute_work(struct work_struct *work)
200{
201	struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);
202
203	target_execute_cmd(&cmd->se_cmd);
204}
205
206/*
207 * Receive write data frame.
208 */
209void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
210{
211	struct se_cmd *se_cmd = &cmd->se_cmd;
212	struct fc_seq *seq = cmd->seq;
213	struct fc_exch *ep;
214	struct fc_lport *lport;
215	struct fc_frame_header *fh;
216	struct scatterlist *sg = NULL;
217	u32 mem_off = 0;
218	u32 rel_off;
219	size_t frame_len;
220	size_t mem_len = 0;
221	size_t tlen;
222	struct page *page = NULL;
223	void *page_addr;
224	void *from;
225	void *to;
226	u32 f_ctl;
227	void *buf;
228
229	fh = fc_frame_header_get(fp);
230	if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
231		goto drop;
232
233	f_ctl = ntoh24(fh->fh_f_ctl);
234	ep = fc_seq_exch(seq);
235	lport = ep->lp;
236	if (cmd->was_ddp_setup) {
237		BUG_ON(!ep);
238		BUG_ON(!lport);
239		/*
240		 * Since DDP (Large Rx offload) was setup for this request,
241		 * payload is expected to be copied directly to user buffers.
242		 */
243		buf = fc_frame_payload_get(fp, 1);
244		if (buf)
245			pr_err("%s: xid 0x%x, f_ctl 0x%x, cmd->sg %p, "
246				"cmd->sg_cnt 0x%x. DDP was setup"
247				" hence not expected to receive frame with "
248				"payload, Frame will be dropped if"
249				"'Sequence Initiative' bit in f_ctl is"
250				"not set\n", __func__, ep->xid, f_ctl,
251				se_cmd->t_data_sg, se_cmd->t_data_nents);
252		/*
253		 * Invalidate HW DDP context if it was setup for respective
254		 * command. Invalidation of HW DDP context is requited in both
255		 * situation (success and error).
256		 */
257		ft_invl_hw_context(cmd);
258
259		/*
260		 * If "Sequence Initiative (TSI)" bit set in f_ctl, means last
261		 * write data frame is received successfully where payload is
262		 * posted directly to user buffer and only the last frame's
263		 * header is posted in receive queue.
264		 *
265		 * If "Sequence Initiative (TSI)" bit is not set, means error
266		 * condition w.r.t. DDP, hence drop the packet and let explict
267		 * ABORTS from other end of exchange timer trigger the recovery.
268		 */
269		if (f_ctl & FC_FC_SEQ_INIT)
270			goto last_frame;
271		else
272			goto drop;
273	}
274
275	rel_off = ntohl(fh->fh_parm_offset);
276	frame_len = fr_len(fp);
277	if (frame_len <= sizeof(*fh))
278		goto drop;
279	frame_len -= sizeof(*fh);
280	from = fc_frame_payload_get(fp, 0);
281	if (rel_off >= se_cmd->data_length)
282		goto drop;
283	if (frame_len + rel_off > se_cmd->data_length)
284		frame_len = se_cmd->data_length - rel_off;
285
286	/*
287	 * Setup to use first mem list entry, unless no data.
288	 */
289	BUG_ON(frame_len && !se_cmd->t_data_sg);
290	if (frame_len) {
291		sg = se_cmd->t_data_sg;
292		mem_len = sg->length;
293		mem_off = sg->offset;
294		page = sg_page(sg);
295	}
296
297	while (frame_len) {
298		if (!mem_len) {
299			sg = sg_next(sg);
300			mem_len = sg->length;
301			mem_off = sg->offset;
302			page = sg_page(sg);
303		}
304		if (rel_off >= mem_len) {
305			rel_off -= mem_len;
306			mem_len = 0;
307			continue;
308		}
309		mem_off += rel_off;
310		mem_len -= rel_off;
311		rel_off = 0;
312
313		tlen = min(mem_len, frame_len);
314
315		to = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
316		page_addr = to;
317		to += mem_off & ~PAGE_MASK;
318		tlen = min(tlen, (size_t)(PAGE_SIZE -
319					  (mem_off & ~PAGE_MASK)));
320		memcpy(to, from, tlen);
321		kunmap_atomic(page_addr);
322
323		from += tlen;
324		frame_len -= tlen;
325		mem_off += tlen;
326		mem_len -= tlen;
327		cmd->write_data_len += tlen;
328	}
329last_frame:
330	if (cmd->write_data_len == se_cmd->data_length) {
331		INIT_WORK(&cmd->work, ft_execute_work);
332		queue_work(cmd->sess->tport->tpg->workqueue, &cmd->work);
333	}
334drop:
335	fc_frame_free(fp);
336}
337
338/*
339 * Handle and cleanup any HW specific resources if
340 * received ABORTS, errors, timeouts.
341 */
342void ft_invl_hw_context(struct ft_cmd *cmd)
343{
344	struct fc_seq *seq;
345	struct fc_exch *ep = NULL;
346	struct fc_lport *lport = NULL;
347
348	BUG_ON(!cmd);
349	seq = cmd->seq;
350
351	/* Cleanup the DDP context in HW if DDP was setup */
352	if (cmd->was_ddp_setup && seq) {
353		ep = fc_seq_exch(seq);
354		if (ep) {
355			lport = ep->lp;
356			if (lport && (ep->xid <= lport->lro_xid)) {
357				/*
358				 * "ddp_done" trigger invalidation of HW
359				 * specific DDP context
360				 */
361				cmd->write_data_len = lport->tt.ddp_done(lport,
362								      ep->xid);
363
364				/*
365				 * Resetting same variable to indicate HW's
366				 * DDP context has been invalidated to avoid
367				 * re_invalidation of same context (context is
368				 * identified using ep->xid)
369				 */
370				cmd->was_ddp_setup = 0;
371			}
372		}
373	}
374}
375