target: Make all control CDBs scatter-gather
[linux-2.6.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 fc_frame *fp = NULL;
69         struct fc_exch *ep;
70         struct fc_lport *lport;
71         struct se_mem *mem;
72         size_t remaining;
73         u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
74         u32 mem_off;
75         u32 fh_off = 0;
76         u32 frame_off = 0;
77         size_t frame_len = 0;
78         size_t mem_len;
79         size_t tlen;
80         size_t off_in_page;
81         struct page *page;
82         int use_sg;
83         int error;
84         void *page_addr;
85         void *from;
86         void *to = NULL;
87
88         ep = fc_seq_exch(cmd->seq);
89         lport = ep->lp;
90         cmd->seq = lport->tt.seq_start_next(cmd->seq);
91
92         remaining = se_cmd->data_length;
93
94         /*
95          * Setup to use first mem list entry, unless no data.
96          */
97         BUG_ON(remaining && list_empty(&se_cmd->t_mem_list));
98         if (remaining) {
99                 mem = list_first_entry(&se_cmd->t_mem_list,
100                          struct se_mem, se_list);
101                 mem_len = mem->se_len;
102                 mem_off = mem->se_off;
103                 page = mem->se_page;
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                 if (!mem_len) {
111                         BUG_ON(!mem);
112                         mem = list_entry(mem->se_list.next,
113                                 struct se_mem, se_list);
114                         mem_len = min((size_t)mem->se_len, remaining);
115                         mem_off = mem->se_off;
116                         page = mem->se_page;
117                 }
118                 if (!frame_len) {
119                         /*
120                          * If lport's has capability of Large Send Offload LSO)
121                          * , then allow 'frame_len' to be as big as 'lso_max'
122                          * if indicated transfer length is >= lport->lso_max
123                          */
124                         frame_len = (lport->seq_offload) ? lport->lso_max :
125                                                           cmd->sess->max_frame;
126                         frame_len = min(frame_len, remaining);
127                         fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
128                         if (!fp)
129                                 return -ENOMEM;
130                         to = fc_frame_payload_get(fp, 0);
131                         fh_off = frame_off;
132                         frame_off += frame_len;
133                         /*
134                          * Setup the frame's max payload which is used by base
135                          * driver to indicate HW about max frame size, so that
136                          * HW can do fragmentation appropriately based on
137                          * "gso_max_size" of underline netdev.
138                          */
139                         fr_max_payload(fp) = cmd->sess->max_frame;
140                 }
141                 tlen = min(mem_len, frame_len);
142
143                 if (use_sg) {
144                         off_in_page = mem_off;
145                         BUG_ON(!page);
146                         get_page(page);
147                         skb_fill_page_desc(fp_skb(fp),
148                                            skb_shinfo(fp_skb(fp))->nr_frags,
149                                            page, off_in_page, tlen);
150                         fr_len(fp) += tlen;
151                         fp_skb(fp)->data_len += tlen;
152                         fp_skb(fp)->truesize +=
153                                         PAGE_SIZE << compound_order(page);
154                 } else {
155                         BUG_ON(!page);
156                         from = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
157                                            KM_SOFTIRQ0);
158                         page_addr = from;
159                         from += mem_off & ~PAGE_MASK;
160                         tlen = min(tlen, (size_t)(PAGE_SIZE -
161                                                 (mem_off & ~PAGE_MASK)));
162                         memcpy(to, from, tlen);
163                         kunmap_atomic(page_addr, KM_SOFTIRQ0);
164                         to += tlen;
165                 }
166
167                 mem_off += tlen;
168                 mem_len -= tlen;
169                 frame_len -= tlen;
170                 remaining -= tlen;
171
172                 if (frame_len &&
173                     (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
174                         continue;
175                 if (!remaining)
176                         f_ctl |= FC_FC_END_SEQ;
177                 fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
178                                FC_TYPE_FCP, f_ctl, fh_off);
179                 error = lport->tt.seq_send(lport, cmd->seq, fp);
180                 if (error) {
181                         /* XXX For now, initiator will retry */
182                         if (printk_ratelimit())
183                                 printk(KERN_ERR "%s: Failed to send frame %p, "
184                                                 "xid <0x%x>, remaining %zu, "
185                                                 "lso_max <0x%x>\n",
186                                                 __func__, fp, ep->xid,
187                                                 remaining, lport->lso_max);
188                 }
189         }
190         return ft_queue_status(se_cmd);
191 }
192
193 /*
194  * Receive write data frame.
195  */
196 void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
197 {
198         struct se_cmd *se_cmd = &cmd->se_cmd;
199         struct fc_seq *seq = cmd->seq;
200         struct fc_exch *ep;
201         struct fc_lport *lport;
202         struct fc_frame_header *fh;
203         struct se_mem *mem;
204         u32 mem_off;
205         u32 rel_off;
206         size_t frame_len;
207         size_t mem_len;
208         size_t tlen;
209         struct page *page;
210         void *page_addr;
211         void *from;
212         void *to;
213         u32 f_ctl;
214         void *buf;
215
216         fh = fc_frame_header_get(fp);
217         if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
218                 goto drop;
219
220         /*
221          * Doesn't expect even single byte of payload. Payload
222          * is expected to be copied directly to user buffers
223          * due to DDP (Large Rx offload) feature, hence
224          * BUG_ON if BUF is non-NULL
225          */
226         buf = fc_frame_payload_get(fp, 1);
227         if (cmd->was_ddp_setup && buf) {
228                 printk(KERN_INFO "%s: When DDP was setup, not expected to"
229                                  "receive frame with payload, Payload shall be"
230                                  "copied directly to buffer instead of coming "
231                                  "via. legacy receive queues\n", __func__);
232                 BUG_ON(buf);
233         }
234
235         /*
236          * If ft_cmd indicated 'ddp_setup', in that case only the last frame
237          * should come with 'TSI bit being set'. If 'TSI bit is not set and if
238          * data frame appears here, means error condition. In both the cases
239          * release the DDP context (ddp_put) and in error case, as well
240          * initiate error recovery mechanism.
241          */
242         ep = fc_seq_exch(seq);
243         if (cmd->was_ddp_setup) {
244                 BUG_ON(!ep);
245                 lport = ep->lp;
246                 BUG_ON(!lport);
247         }
248         if (cmd->was_ddp_setup && ep->xid != FC_XID_UNKNOWN) {
249                 f_ctl = ntoh24(fh->fh_f_ctl);
250                 /*
251                  * If TSI bit set in f_ctl, means last write data frame is
252                  * received successfully where payload is posted directly
253                  * to user buffer and only the last frame's header is posted
254                  * in legacy receive queue
255                  */
256                 if (f_ctl & FC_FC_SEQ_INIT) { /* TSI bit set in FC frame */
257                         cmd->write_data_len = lport->tt.ddp_done(lport,
258                                                                 ep->xid);
259                         goto last_frame;
260                 } else {
261                         /*
262                          * Updating the write_data_len may be meaningless at
263                          * this point, but just in case if required in future
264                          * for debugging or any other purpose
265                          */
266                         printk(KERN_ERR "%s: Received frame with TSI bit not"
267                                         " being SET, dropping the frame, "
268                                         "cmd->sg <%p>, cmd->sg_cnt <0x%x>\n",
269                                         __func__, cmd->sg, cmd->sg_cnt);
270                         cmd->write_data_len = lport->tt.ddp_done(lport,
271                                                               ep->xid);
272                         lport->tt.seq_exch_abort(cmd->seq, 0);
273                         goto drop;
274                 }
275         }
276
277         rel_off = ntohl(fh->fh_parm_offset);
278         frame_len = fr_len(fp);
279         if (frame_len <= sizeof(*fh))
280                 goto drop;
281         frame_len -= sizeof(*fh);
282         from = fc_frame_payload_get(fp, 0);
283         if (rel_off >= se_cmd->data_length)
284                 goto drop;
285         if (frame_len + rel_off > se_cmd->data_length)
286                 frame_len = se_cmd->data_length - rel_off;
287
288         /*
289          * Setup to use first mem list entry, unless no data.
290          */
291         BUG_ON(frame_len && list_empty(&se_cmd->t_mem_list));
292         if (frame_len) {
293                 mem = list_first_entry(&se_cmd->t_mem_list,
294                                        struct se_mem, se_list);
295                 mem_len = mem->se_len;
296                 mem_off = mem->se_off;
297                 page = mem->se_page;
298         }
299
300         while (frame_len) {
301                 if (!mem_len) {
302                         BUG_ON(!mem);
303                         mem = list_entry(mem->se_list.next,
304                                          struct se_mem, se_list);
305                         mem_len = mem->se_len;
306                         mem_off = mem->se_off;
307                         page = mem->se_page;
308                 }
309                 if (rel_off >= mem_len) {
310                         rel_off -= mem_len;
311                         mem_len = 0;
312                         continue;
313                 }
314                 mem_off += rel_off;
315                 mem_len -= rel_off;
316                 rel_off = 0;
317
318                 tlen = min(mem_len, frame_len);
319
320                 to = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
321                                  KM_SOFTIRQ0);
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, KM_SOFTIRQ0);
328
329                 from += tlen;
330                 frame_len -= tlen;
331                 mem_off += tlen;
332                 mem_len -= tlen;
333                 cmd->write_data_len += tlen;
334         }
335 last_frame:
336         if (cmd->write_data_len == se_cmd->data_length)
337                 transport_generic_handle_data(se_cmd);
338 drop:
339         fc_frame_free(fp);
340 }