Enabling ftrace for kernel debugging.
[kvmfornfv.git] / kernel / drivers / target / tcm_fc / tfc_io.c
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  */
54 int 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         }
195 queue_status:
196         return ft_queue_status(se_cmd);
197 }
198
199 static 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  */
209 void 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         }
329 last_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         }
334 drop:
335         fc_frame_free(fp);
336 }
337
338 /*
339  * Handle and cleanup any HW specific resources if
340  * received ABORTS, errors, timeouts.
341  */
342 void 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 }