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/scsi.h>
43#include <scsi/scsi_host.h>
44#include <scsi/scsi_device.h>
45#include <scsi/scsi_cmnd.h>
46#include <scsi/libfc.h>
47#include <scsi/fc_encode.h>
48
49#include <target/target_core_base.h>
50#include <target/target_core_fabric.h>
51#include <target/target_core_configfs.h>
52#include <target/configfs_macros.h>
53
54#include "tcm_fc.h"
55
56/*
57 * Deliver read data back to initiator.
58 * XXX TBD handle resource problems later.
59 */
60int ft_queue_data_in(struct se_cmd *se_cmd)
61{
62	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
63	struct fc_frame *fp = NULL;
64	struct fc_exch *ep;
65	struct fc_lport *lport;
66	struct scatterlist *sg = NULL;
67	size_t remaining;
68	u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
69	u32 mem_off = 0;
70	u32 fh_off = 0;
71	u32 frame_off = 0;
72	size_t frame_len = 0;
73	size_t mem_len = 0;
74	size_t tlen;
75	size_t off_in_page;
76	struct page *page = NULL;
77	int use_sg;
78	int error;
79	void *page_addr;
80	void *from;
81	void *to = NULL;
82
83	if (cmd->aborted)
84		return 0;
85
86	if (se_cmd->scsi_status == SAM_STAT_TASK_SET_FULL)
87		goto queue_status;
88
89	ep = fc_seq_exch(cmd->seq);
90	lport = ep->lp;
91	cmd->seq = lport->tt.seq_start_next(cmd->seq);
92
93	remaining = se_cmd->data_length;
94
95	/*
96	 * Setup to use first mem list entry, unless no data.
97	 */
98	BUG_ON(remaining && !se_cmd->t_data_sg);
99	if (remaining) {
100		sg = se_cmd->t_data_sg;
101		mem_len = sg->length;
102		mem_off = sg->offset;
103		page = sg_page(sg);
104	}
105
106	/* no scatter/gather in skb for odd word length due to fc_seq_send() */
107	use_sg = !(remaining % 4);
108
109	while (remaining) {
110		struct fc_seq *seq = cmd->seq;
111
112		if (!seq) {
113			pr_debug("%s: Command aborted, xid 0x%x\n",
114				 __func__, ep->xid);
115			break;
116		}
117		if (!mem_len) {
118			sg = sg_next(sg);
119			mem_len = min((size_t)sg->length, remaining);
120			mem_off = sg->offset;
121			page = sg_page(sg);
122		}
123		if (!frame_len) {
124			/*
125			 * If lport's has capability of Large Send Offload LSO)
126			 * , then allow 'frame_len' to be as big as 'lso_max'
127			 * if indicated transfer length is >= lport->lso_max
128			 */
129			frame_len = (lport->seq_offload) ? lport->lso_max :
130							  cmd->sess->max_frame;
131			frame_len = min(frame_len, remaining);
132			fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
133			if (!fp)
134				return -ENOMEM;
135			to = fc_frame_payload_get(fp, 0);
136			fh_off = frame_off;
137			frame_off += frame_len;
138			/*
139			 * Setup the frame's max payload which is used by base
140			 * driver to indicate HW about max frame size, so that
141			 * HW can do fragmentation appropriately based on
142			 * "gso_max_size" of underline netdev.
143			 */
144			fr_max_payload(fp) = cmd->sess->max_frame;
145		}
146		tlen = min(mem_len, frame_len);
147
148		if (use_sg) {
149			off_in_page = mem_off;
150			BUG_ON(!page);
151			get_page(page);
152			skb_fill_page_desc(fp_skb(fp),
153					   skb_shinfo(fp_skb(fp))->nr_frags,
154					   page, off_in_page, tlen);
155			fr_len(fp) += tlen;
156			fp_skb(fp)->data_len += tlen;
157			fp_skb(fp)->truesize +=
158					PAGE_SIZE << compound_order(page);
159		} else {
160			BUG_ON(!page);
161			from = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
162			page_addr = from;
163			from += mem_off & ~PAGE_MASK;
164			tlen = min(tlen, (size_t)(PAGE_SIZE -
165						(mem_off & ~PAGE_MASK)));
166			memcpy(to, from, tlen);
167			kunmap_atomic(page_addr);
168			to += tlen;
169		}
170
171		mem_off += tlen;
172		mem_len -= tlen;
173		frame_len -= tlen;
174		remaining -= tlen;
175
176		if (frame_len &&
177		    (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
178			continue;
179		if (!remaining)
180			f_ctl |= FC_FC_END_SEQ;
181		fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
182			       FC_TYPE_FCP, f_ctl, fh_off);
183		error = lport->tt.seq_send(lport, seq, fp);
184		if (error) {
185			pr_info_ratelimited("%s: Failed to send frame %p, "
186						"xid <0x%x>, remaining %zu, "
187						"lso_max <0x%x>\n",
188						__func__, fp, ep->xid,
189						remaining, lport->lso_max);
190			/*
191			 * Go ahead and set TASK_SET_FULL status ignoring the
192			 * rest of the DataIN, and immediately attempt to
193			 * send the response via ft_queue_status() in order
194			 * to notify the initiator that it should reduce it's
195			 * per LUN queue_depth.
196			 */
197			se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
198			break;
199		}
200	}
201queue_status:
202	return ft_queue_status(se_cmd);
203}
204
205static void ft_execute_work(struct work_struct *work)
206{
207	struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);
208
209	target_execute_cmd(&cmd->se_cmd);
210}
211
212/*
213 * Receive write data frame.
214 */
215void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
216{
217	struct se_cmd *se_cmd = &cmd->se_cmd;
218	struct fc_seq *seq = cmd->seq;
219	struct fc_exch *ep;
220	struct fc_lport *lport;
221	struct fc_frame_header *fh;
222	struct scatterlist *sg = NULL;
223	u32 mem_off = 0;
224	u32 rel_off;
225	size_t frame_len;
226	size_t mem_len = 0;
227	size_t tlen;
228	struct page *page = NULL;
229	void *page_addr;
230	void *from;
231	void *to;
232	u32 f_ctl;
233	void *buf;
234
235	fh = fc_frame_header_get(fp);
236	if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
237		goto drop;
238
239	f_ctl = ntoh24(fh->fh_f_ctl);
240	ep = fc_seq_exch(seq);
241	lport = ep->lp;
242	if (cmd->was_ddp_setup) {
243		BUG_ON(!ep);
244		BUG_ON(!lport);
245		/*
246		 * Since DDP (Large Rx offload) was setup for this request,
247		 * payload is expected to be copied directly to user buffers.
248		 */
249		buf = fc_frame_payload_get(fp, 1);
250		if (buf)
251			pr_err("%s: xid 0x%x, f_ctl 0x%x, cmd->sg %p, "
252				"cmd->sg_cnt 0x%x. DDP was setup"
253				" hence not expected to receive frame with "
254				"payload, Frame will be dropped if"
255				"'Sequence Initiative' bit in f_ctl is"
256				"not set\n", __func__, ep->xid, f_ctl,
257				se_cmd->t_data_sg, se_cmd->t_data_nents);
258		/*
259		 * Invalidate HW DDP context if it was setup for respective
260		 * command. Invalidation of HW DDP context is requited in both
261		 * situation (success and error).
262		 */
263		ft_invl_hw_context(cmd);
264
265		/*
266		 * If "Sequence Initiative (TSI)" bit set in f_ctl, means last
267		 * write data frame is received successfully where payload is
268		 * posted directly to user buffer and only the last frame's
269		 * header is posted in receive queue.
270		 *
271		 * If "Sequence Initiative (TSI)" bit is not set, means error
272		 * condition w.r.t. DDP, hence drop the packet and let explict
273		 * ABORTS from other end of exchange timer trigger the recovery.
274		 */
275		if (f_ctl & FC_FC_SEQ_INIT)
276			goto last_frame;
277		else
278			goto drop;
279	}
280
281	rel_off = ntohl(fh->fh_parm_offset);
282	frame_len = fr_len(fp);
283	if (frame_len <= sizeof(*fh))
284		goto drop;
285	frame_len -= sizeof(*fh);
286	from = fc_frame_payload_get(fp, 0);
287	if (rel_off >= se_cmd->data_length)
288		goto drop;
289	if (frame_len + rel_off > se_cmd->data_length)
290		frame_len = se_cmd->data_length - rel_off;
291
292	/*
293	 * Setup to use first mem list entry, unless no data.
294	 */
295	BUG_ON(frame_len && !se_cmd->t_data_sg);
296	if (frame_len) {
297		sg = se_cmd->t_data_sg;
298		mem_len = sg->length;
299		mem_off = sg->offset;
300		page = sg_page(sg);
301	}
302
303	while (frame_len) {
304		if (!mem_len) {
305			sg = sg_next(sg);
306			mem_len = sg->length;
307			mem_off = sg->offset;
308			page = sg_page(sg);
309		}
310		if (rel_off >= mem_len) {
311			rel_off -= mem_len;
312			mem_len = 0;
313			continue;
314		}
315		mem_off += rel_off;
316		mem_len -= rel_off;
317		rel_off = 0;
318
319		tlen = min(mem_len, frame_len);
320
321		to = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
322		page_addr = to;
323		to += mem_off & ~PAGE_MASK;
324		tlen = min(tlen, (size_t)(PAGE_SIZE -
325					  (mem_off & ~PAGE_MASK)));
326		memcpy(to, from, tlen);
327		kunmap_atomic(page_addr);
328
329		from += tlen;
330		frame_len -= tlen;
331		mem_off += tlen;
332		mem_len -= tlen;
333		cmd->write_data_len += tlen;
334	}
335last_frame:
336	if (cmd->write_data_len == se_cmd->data_length) {
337		INIT_WORK(&cmd->work, ft_execute_work);
338		queue_work(cmd->sess->tport->tpg->workqueue, &cmd->work);
339	}
340drop:
341	fc_frame_free(fp);
342}
343
344/*
345 * Handle and cleanup any HW specific resources if
346 * received ABORTS, errors, timeouts.
347 */
348void ft_invl_hw_context(struct ft_cmd *cmd)
349{
350	struct fc_seq *seq;
351	struct fc_exch *ep = NULL;
352	struct fc_lport *lport = NULL;
353
354	BUG_ON(!cmd);
355	seq = cmd->seq;
356
357	/* Cleanup the DDP context in HW if DDP was setup */
358	if (cmd->was_ddp_setup && seq) {
359		ep = fc_seq_exch(seq);
360		if (ep) {
361			lport = ep->lp;
362			if (lport && (ep->xid <= lport->lro_xid))
363				/*
364				 * "ddp_done" trigger invalidation of HW
365				 * specific DDP context
366				 */
367				cmd->write_data_len = lport->tt.ddp_done(lport,
368								      ep->xid);
369
370				/*
371				 * Resetting same variable to indicate HW's
372				 * DDP context has been invalidated to avoid
373				 * re_invalidation of same context (context is
374				 * identified using ep->xid)
375				 */
376				cmd->was_ddp_setup = 0;
377		}
378	}
379}
380