target: More core cleanups from AGrover (round 2)
[linux-3.10.git] / 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/version.h>
32 #include <generated/utsrelease.h>
33 #include <linux/utsname.h>
34 #include <linux/init.h>
35 #include <linux/slab.h>
36 #include <linux/kthread.h>
37 #include <linux/types.h>
38 #include <linux/string.h>
39 #include <linux/configfs.h>
40 #include <linux/ctype.h>
41 #include <linux/hash.h>
42 #include <asm/unaligned.h>
43 #include <scsi/scsi.h>
44 #include <scsi/scsi_host.h>
45 #include <scsi/scsi_device.h>
46 #include <scsi/scsi_cmnd.h>
47 #include <scsi/libfc.h>
48 #include <scsi/fc_encode.h>
49
50 #include <target/target_core_base.h>
51 #include <target/target_core_transport.h>
52 #include <target/target_core_fabric_ops.h>
53 #include <target/target_core_device.h>
54 #include <target/target_core_tpg.h>
55 #include <target/target_core_configfs.h>
56 #include <target/target_core_base.h>
57 #include <target/configfs_macros.h>
58
59 #include "tcm_fc.h"
60
61 /*
62  * Deliver read data back to initiator.
63  * XXX TBD handle resource problems later.
64  */
65 int ft_queue_data_in(struct se_cmd *se_cmd)
66 {
67         struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
68         struct se_transport_task *task;
69         struct fc_frame *fp = NULL;
70         struct fc_exch *ep;
71         struct fc_lport *lport;
72         struct se_mem *mem;
73         size_t remaining;
74         u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
75         u32 mem_off;
76         u32 fh_off = 0;
77         u32 frame_off = 0;
78         size_t frame_len = 0;
79         size_t mem_len;
80         size_t tlen;
81         size_t off_in_page;
82         struct page *page;
83         int use_sg;
84         int error;
85         void *page_addr;
86         void *from;
87         void *to = NULL;
88
89         ep = fc_seq_exch(cmd->seq);
90         lport = ep->lp;
91         cmd->seq = lport->tt.seq_start_next(cmd->seq);
92
93         task = &se_cmd->t_task;
94         remaining = se_cmd->data_length;
95
96         /*
97          * Setup to use first mem list entry if any.
98          */
99         if (task->t_tasks_se_num) {
100                 mem = list_first_entry(&task->t_mem_list,
101                          struct se_mem, se_list);
102                 mem_len = mem->se_len;
103                 mem_off = mem->se_off;
104                 page = mem->se_page;
105         } else {
106                 mem = NULL;
107                 mem_len = remaining;
108                 mem_off = 0;
109                 page = NULL;
110         }
111
112         /* no scatter/gather in skb for odd word length due to fc_seq_send() */
113         use_sg = !(remaining % 4);
114
115         while (remaining) {
116                 if (!mem_len) {
117                         BUG_ON(!mem);
118                         mem = list_entry(mem->se_list.next,
119                                 struct se_mem, se_list);
120                         mem_len = min((size_t)mem->se_len, remaining);
121                         mem_off = mem->se_off;
122                         page = mem->se_page;
123                 }
124                 if (!frame_len) {
125                         /*
126                          * If lport's has capability of Large Send Offload LSO)
127                          * , then allow 'frame_len' to be as big as 'lso_max'
128                          * if indicated transfer length is >= lport->lso_max
129                          */
130                         frame_len = (lport->seq_offload) ? lport->lso_max :
131                                                           cmd->sess->max_frame;
132                         frame_len = min(frame_len, remaining);
133                         fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
134                         if (!fp)
135                                 return -ENOMEM;
136                         to = fc_frame_payload_get(fp, 0);
137                         fh_off = frame_off;
138                         frame_off += frame_len;
139                         /*
140                          * Setup the frame's max payload which is used by base
141                          * driver to indicate HW about max frame size, so that
142                          * HW can do fragmentation appropriately based on
143                          * "gso_max_size" of underline netdev.
144                          */
145                         fr_max_payload(fp) = cmd->sess->max_frame;
146                 }
147                 tlen = min(mem_len, frame_len);
148
149                 if (use_sg) {
150                         if (!mem) {
151                                 BUG_ON(!task->t_task_buf);
152                                 page_addr = task->t_task_buf + mem_off;
153                                 /*
154                                  * In this case, offset is 'offset_in_page' of
155                                  * (t_task_buf + mem_off) instead of 'mem_off'.
156                                  */
157                                 off_in_page = offset_in_page(page_addr);
158                                 page = virt_to_page(page_addr);
159                                 tlen = min(tlen, PAGE_SIZE - off_in_page);
160                         } else
161                                 off_in_page = mem_off;
162                         BUG_ON(!page);
163                         get_page(page);
164                         skb_fill_page_desc(fp_skb(fp),
165                                            skb_shinfo(fp_skb(fp))->nr_frags,
166                                            page, off_in_page, tlen);
167                         fr_len(fp) += tlen;
168                         fp_skb(fp)->data_len += tlen;
169                         fp_skb(fp)->truesize +=
170                                         PAGE_SIZE << compound_order(page);
171                 } else if (mem) {
172                         BUG_ON(!page);
173                         from = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
174                                            KM_SOFTIRQ0);
175                         page_addr = from;
176                         from += mem_off & ~PAGE_MASK;
177                         tlen = min(tlen, (size_t)(PAGE_SIZE -
178                                                 (mem_off & ~PAGE_MASK)));
179                         memcpy(to, from, tlen);
180                         kunmap_atomic(page_addr, KM_SOFTIRQ0);
181                         to += tlen;
182                 } else {
183                         from = task->t_task_buf + mem_off;
184                         memcpy(to, from, tlen);
185                         to += tlen;
186                 }
187
188                 mem_off += tlen;
189                 mem_len -= tlen;
190                 frame_len -= tlen;
191                 remaining -= tlen;
192
193                 if (frame_len &&
194                     (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
195                         continue;
196                 if (!remaining)
197                         f_ctl |= FC_FC_END_SEQ;
198                 fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
199                                FC_TYPE_FCP, f_ctl, fh_off);
200                 error = lport->tt.seq_send(lport, cmd->seq, fp);
201                 if (error) {
202                         /* XXX For now, initiator will retry */
203                         if (printk_ratelimit())
204                                 printk(KERN_ERR "%s: Failed to send frame %p, "
205                                                 "xid <0x%x>, remaining %zu, "
206                                                 "lso_max <0x%x>\n",
207                                                 __func__, fp, ep->xid,
208                                                 remaining, lport->lso_max);
209                 }
210         }
211         return ft_queue_status(se_cmd);
212 }
213
214 /*
215  * Receive write data frame.
216  */
217 void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
218 {
219         struct se_cmd *se_cmd = &cmd->se_cmd;
220         struct fc_seq *seq = cmd->seq;
221         struct fc_exch *ep;
222         struct fc_lport *lport;
223         struct se_transport_task *task;
224         struct fc_frame_header *fh;
225         struct se_mem *mem;
226         u32 mem_off;
227         u32 rel_off;
228         size_t frame_len;
229         size_t mem_len;
230         size_t tlen;
231         struct page *page;
232         void *page_addr;
233         void *from;
234         void *to;
235         u32 f_ctl;
236         void *buf;
237
238         task = &se_cmd->t_task;
239
240         fh = fc_frame_header_get(fp);
241         if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
242                 goto drop;
243
244         /*
245          * Doesn't expect even single byte of payload. Payload
246          * is expected to be copied directly to user buffers
247          * due to DDP (Large Rx offload) feature, hence
248          * BUG_ON if BUF is non-NULL
249          */
250         buf = fc_frame_payload_get(fp, 1);
251         if (cmd->was_ddp_setup && buf) {
252                 printk(KERN_INFO "%s: When DDP was setup, not expected to"
253                                  "receive frame with payload, Payload shall be"
254                                  "copied directly to buffer instead of coming "
255                                  "via. legacy receive queues\n", __func__);
256                 BUG_ON(buf);
257         }
258
259         /*
260          * If ft_cmd indicated 'ddp_setup', in that case only the last frame
261          * should come with 'TSI bit being set'. If 'TSI bit is not set and if
262          * data frame appears here, means error condition. In both the cases
263          * release the DDP context (ddp_put) and in error case, as well
264          * initiate error recovery mechanism.
265          */
266         ep = fc_seq_exch(seq);
267         if (cmd->was_ddp_setup) {
268                 BUG_ON(!ep);
269                 lport = ep->lp;
270                 BUG_ON(!lport);
271         }
272         if (cmd->was_ddp_setup && ep->xid != FC_XID_UNKNOWN) {
273                 f_ctl = ntoh24(fh->fh_f_ctl);
274                 /*
275                  * If TSI bit set in f_ctl, means last write data frame is
276                  * received successfully where payload is posted directly
277                  * to user buffer and only the last frame's header is posted
278                  * in legacy receive queue
279                  */
280                 if (f_ctl & FC_FC_SEQ_INIT) { /* TSI bit set in FC frame */
281                         cmd->write_data_len = lport->tt.ddp_done(lport,
282                                                                 ep->xid);
283                         goto last_frame;
284                 } else {
285                         /*
286                          * Updating the write_data_len may be meaningless at
287                          * this point, but just in case if required in future
288                          * for debugging or any other purpose
289                          */
290                         printk(KERN_ERR "%s: Received frame with TSI bit not"
291                                         " being SET, dropping the frame, "
292                                         "cmd->sg <%p>, cmd->sg_cnt <0x%x>\n",
293                                         __func__, cmd->sg, cmd->sg_cnt);
294                         cmd->write_data_len = lport->tt.ddp_done(lport,
295                                                               ep->xid);
296                         lport->tt.seq_exch_abort(cmd->seq, 0);
297                         goto drop;
298                 }
299         }
300
301         rel_off = ntohl(fh->fh_parm_offset);
302         frame_len = fr_len(fp);
303         if (frame_len <= sizeof(*fh))
304                 goto drop;
305         frame_len -= sizeof(*fh);
306         from = fc_frame_payload_get(fp, 0);
307         if (rel_off >= se_cmd->data_length)
308                 goto drop;
309         if (frame_len + rel_off > se_cmd->data_length)
310                 frame_len = se_cmd->data_length - rel_off;
311
312         /*
313          * Setup to use first mem list entry if any.
314          */
315         if (task->t_tasks_se_num) {
316                 mem = list_first_entry(&task->t_mem_list,
317                                        struct se_mem, se_list);
318                 mem_len = mem->se_len;
319                 mem_off = mem->se_off;
320                 page = mem->se_page;
321         } else {
322                 mem = NULL;
323                 page = NULL;
324                 mem_off = 0;
325                 mem_len = frame_len;
326         }
327
328         while (frame_len) {
329                 if (!mem_len) {
330                         BUG_ON(!mem);
331                         mem = list_entry(mem->se_list.next,
332                                          struct se_mem, se_list);
333                         mem_len = mem->se_len;
334                         mem_off = mem->se_off;
335                         page = mem->se_page;
336                 }
337                 if (rel_off >= mem_len) {
338                         rel_off -= mem_len;
339                         mem_len = 0;
340                         continue;
341                 }
342                 mem_off += rel_off;
343                 mem_len -= rel_off;
344                 rel_off = 0;
345
346                 tlen = min(mem_len, frame_len);
347
348                 if (mem) {
349                         to = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
350                                          KM_SOFTIRQ0);
351                         page_addr = to;
352                         to += mem_off & ~PAGE_MASK;
353                         tlen = min(tlen, (size_t)(PAGE_SIZE -
354                                                 (mem_off & ~PAGE_MASK)));
355                         memcpy(to, from, tlen);
356                         kunmap_atomic(page_addr, KM_SOFTIRQ0);
357                 } else {
358                         to = task->t_task_buf + mem_off;
359                         memcpy(to, from, tlen);
360                 }
361                 from += tlen;
362                 frame_len -= tlen;
363                 mem_off += tlen;
364                 mem_len -= tlen;
365                 cmd->write_data_len += tlen;
366         }
367 last_frame:
368         if (cmd->write_data_len == se_cmd->data_length)
369                 transport_generic_handle_data(se_cmd);
370 drop:
371         fc_frame_free(fp);
372 }