11e6483fc1276013e92234cb1c19538d6b09994a
[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 <linux/ratelimit.h>
43 #include <asm/unaligned.h>
44 #include <scsi/scsi.h>
45 #include <scsi/scsi_host.h>
46 #include <scsi/scsi_device.h>
47 #include <scsi/scsi_cmnd.h>
48 #include <scsi/libfc.h>
49 #include <scsi/fc_encode.h>
50
51 #include <target/target_core_base.h>
52 #include <target/target_core_transport.h>
53 #include <target/target_core_fabric_ops.h>
54 #include <target/target_core_device.h>
55 #include <target/target_core_tpg.h>
56 #include <target/target_core_configfs.h>
57 #include <target/target_core_base.h>
58 #include <target/configfs_macros.h>
59
60 #include "tcm_fc.h"
61
62 /*
63  * Deliver read data back to initiator.
64  * XXX TBD handle resource problems later.
65  */
66 int ft_queue_data_in(struct se_cmd *se_cmd)
67 {
68         struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
69         struct fc_frame *fp = NULL;
70         struct fc_exch *ep;
71         struct fc_lport *lport;
72         struct scatterlist *sg = NULL;
73         size_t remaining;
74         u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
75         u32 mem_off = 0;
76         u32 fh_off = 0;
77         u32 frame_off = 0;
78         size_t frame_len = 0;
79         size_t mem_len = 0;
80         size_t tlen;
81         size_t off_in_page;
82         struct page *page = NULL;
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         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                 if (!mem_len) {
111                         sg = sg_next(sg);
112                         mem_len = min((size_t)sg->length, remaining);
113                         mem_off = sg->offset;
114                         page = sg_page(sg);
115                 }
116                 if (!frame_len) {
117                         /*
118                          * If lport's has capability of Large Send Offload LSO)
119                          * , then allow 'frame_len' to be as big as 'lso_max'
120                          * if indicated transfer length is >= lport->lso_max
121                          */
122                         frame_len = (lport->seq_offload) ? lport->lso_max :
123                                                           cmd->sess->max_frame;
124                         frame_len = min(frame_len, remaining);
125                         fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
126                         if (!fp)
127                                 return -ENOMEM;
128                         to = fc_frame_payload_get(fp, 0);
129                         fh_off = frame_off;
130                         frame_off += frame_len;
131                         /*
132                          * Setup the frame's max payload which is used by base
133                          * driver to indicate HW about max frame size, so that
134                          * HW can do fragmentation appropriately based on
135                          * "gso_max_size" of underline netdev.
136                          */
137                         fr_max_payload(fp) = cmd->sess->max_frame;
138                 }
139                 tlen = min(mem_len, frame_len);
140
141                 if (use_sg) {
142                         off_in_page = mem_off;
143                         BUG_ON(!page);
144                         get_page(page);
145                         skb_fill_page_desc(fp_skb(fp),
146                                            skb_shinfo(fp_skb(fp))->nr_frags,
147                                            page, off_in_page, tlen);
148                         fr_len(fp) += tlen;
149                         fp_skb(fp)->data_len += tlen;
150                         fp_skb(fp)->truesize +=
151                                         PAGE_SIZE << compound_order(page);
152                 } else {
153                         BUG_ON(!page);
154                         from = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
155                                            KM_SOFTIRQ0);
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, KM_SOFTIRQ0);
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, cmd->seq, fp);
178                 if (error) {
179                         /* XXX For now, initiator will retry */
180                         pr_err_ratelimited("%s: Failed to send frame %p, "
181                                                 "xid <0x%x>, remaining %zu, "
182                                                 "lso_max <0x%x>\n",
183                                                 __func__, fp, ep->xid,
184                                                 remaining, lport->lso_max);
185                 }
186         }
187         return ft_queue_status(se_cmd);
188 }
189
190 /*
191  * Receive write data frame.
192  */
193 void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
194 {
195         struct se_cmd *se_cmd = &cmd->se_cmd;
196         struct fc_seq *seq = cmd->seq;
197         struct fc_exch *ep;
198         struct fc_lport *lport;
199         struct fc_frame_header *fh;
200         struct scatterlist *sg = NULL;
201         u32 mem_off = 0;
202         u32 rel_off;
203         size_t frame_len;
204         size_t mem_len = 0;
205         size_t tlen;
206         struct page *page = NULL;
207         void *page_addr;
208         void *from;
209         void *to;
210         u32 f_ctl;
211         void *buf;
212
213         fh = fc_frame_header_get(fp);
214         if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
215                 goto drop;
216
217         /*
218          * Doesn't expect even single byte of payload. Payload
219          * is expected to be copied directly to user buffers
220          * due to DDP (Large Rx offload) feature, hence
221          * BUG_ON if BUF is non-NULL
222          */
223         buf = fc_frame_payload_get(fp, 1);
224         if (cmd->was_ddp_setup && buf) {
225                 pr_debug("%s: When DDP was setup, not expected to"
226                                  "receive frame with payload, Payload shall be"
227                                  "copied directly to buffer instead of coming "
228                                  "via. legacy receive queues\n", __func__);
229                 BUG_ON(buf);
230         }
231
232         /*
233          * If ft_cmd indicated 'ddp_setup', in that case only the last frame
234          * should come with 'TSI bit being set'. If 'TSI bit is not set and if
235          * data frame appears here, means error condition. In both the cases
236          * release the DDP context (ddp_put) and in error case, as well
237          * initiate error recovery mechanism.
238          */
239         ep = fc_seq_exch(seq);
240         if (cmd->was_ddp_setup) {
241                 BUG_ON(!ep);
242                 lport = ep->lp;
243                 BUG_ON(!lport);
244         }
245         if (cmd->was_ddp_setup && ep->xid != FC_XID_UNKNOWN) {
246                 f_ctl = ntoh24(fh->fh_f_ctl);
247                 /*
248                  * If TSI bit set in f_ctl, means last write data frame is
249                  * received successfully where payload is posted directly
250                  * to user buffer and only the last frame's header is posted
251                  * in legacy receive queue
252                  */
253                 if (f_ctl & FC_FC_SEQ_INIT) { /* TSI bit set in FC frame */
254                         cmd->write_data_len = lport->tt.ddp_done(lport,
255                                                                 ep->xid);
256                         goto last_frame;
257                 } else {
258                         /*
259                          * Updating the write_data_len may be meaningless at
260                          * this point, but just in case if required in future
261                          * for debugging or any other purpose
262                          */
263                         pr_err("%s: Received frame with TSI bit not"
264                                         " being SET, dropping the frame, "
265                                         "cmd->sg <%p>, cmd->sg_cnt <0x%x>\n",
266                                         __func__, cmd->sg, cmd->sg_cnt);
267                         cmd->write_data_len = lport->tt.ddp_done(lport,
268                                                               ep->xid);
269                         lport->tt.seq_exch_abort(cmd->seq, 0);
270                         goto drop;
271                 }
272         }
273
274         rel_off = ntohl(fh->fh_parm_offset);
275         frame_len = fr_len(fp);
276         if (frame_len <= sizeof(*fh))
277                 goto drop;
278         frame_len -= sizeof(*fh);
279         from = fc_frame_payload_get(fp, 0);
280         if (rel_off >= se_cmd->data_length)
281                 goto drop;
282         if (frame_len + rel_off > se_cmd->data_length)
283                 frame_len = se_cmd->data_length - rel_off;
284
285         /*
286          * Setup to use first mem list entry, unless no data.
287          */
288         BUG_ON(frame_len && !se_cmd->t_data_sg);
289         if (frame_len) {
290                 sg = se_cmd->t_data_sg;
291                 mem_len = sg->length;
292                 mem_off = sg->offset;
293                 page = sg_page(sg);
294         }
295
296         while (frame_len) {
297                 if (!mem_len) {
298                         sg = sg_next(sg);
299                         mem_len = sg->length;
300                         mem_off = sg->offset;
301                         page = sg_page(sg);
302                 }
303                 if (rel_off >= mem_len) {
304                         rel_off -= mem_len;
305                         mem_len = 0;
306                         continue;
307                 }
308                 mem_off += rel_off;
309                 mem_len -= rel_off;
310                 rel_off = 0;
311
312                 tlen = min(mem_len, frame_len);
313
314                 to = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
315                                  KM_SOFTIRQ0);
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, KM_SOFTIRQ0);
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                 transport_generic_handle_data(se_cmd);
332 drop:
333         fc_frame_free(fp);
334 }