Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
[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/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 scatterlist *sg = NULL;
72         size_t remaining;
73         u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
74         u32 mem_off = 0;
75         u32 fh_off = 0;
76         u32 frame_off = 0;
77         size_t frame_len = 0;
78         size_t mem_len = 0;
79         size_t tlen;
80         size_t off_in_page;
81         struct page *page = NULL;
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 && !se_cmd->t_data_sg);
98         if (remaining) {
99                 sg = se_cmd->t_data_sg;
100                 mem_len = sg->length;
101                 mem_off = sg->offset;
102                 page = sg_page(sg);
103         }
104
105         /* no scatter/gather in skb for odd word length due to fc_seq_send() */
106         use_sg = !(remaining % 4);
107
108         while (remaining) {
109                 if (!mem_len) {
110                         sg = sg_next(sg);
111                         mem_len = min((size_t)sg->length, remaining);
112                         mem_off = sg->offset;
113                         page = sg_page(sg);
114                 }
115                 if (!frame_len) {
116                         /*
117                          * If lport's has capability of Large Send Offload LSO)
118                          * , then allow 'frame_len' to be as big as 'lso_max'
119                          * if indicated transfer length is >= lport->lso_max
120                          */
121                         frame_len = (lport->seq_offload) ? lport->lso_max :
122                                                           cmd->sess->max_frame;
123                         frame_len = min(frame_len, remaining);
124                         fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
125                         if (!fp)
126                                 return -ENOMEM;
127                         to = fc_frame_payload_get(fp, 0);
128                         fh_off = frame_off;
129                         frame_off += frame_len;
130                         /*
131                          * Setup the frame's max payload which is used by base
132                          * driver to indicate HW about max frame size, so that
133                          * HW can do fragmentation appropriately based on
134                          * "gso_max_size" of underline netdev.
135                          */
136                         fr_max_payload(fp) = cmd->sess->max_frame;
137                 }
138                 tlen = min(mem_len, frame_len);
139
140                 if (use_sg) {
141                         off_in_page = mem_off;
142                         BUG_ON(!page);
143                         get_page(page);
144                         skb_fill_page_desc(fp_skb(fp),
145                                            skb_shinfo(fp_skb(fp))->nr_frags,
146                                            page, off_in_page, tlen);
147                         fr_len(fp) += tlen;
148                         fp_skb(fp)->data_len += tlen;
149                         fp_skb(fp)->truesize +=
150                                         PAGE_SIZE << compound_order(page);
151                 } else {
152                         BUG_ON(!page);
153                         from = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
154                                            KM_SOFTIRQ0);
155                         page_addr = from;
156                         from += mem_off & ~PAGE_MASK;
157                         tlen = min(tlen, (size_t)(PAGE_SIZE -
158                                                 (mem_off & ~PAGE_MASK)));
159                         memcpy(to, from, tlen);
160                         kunmap_atomic(page_addr, KM_SOFTIRQ0);
161                         to += tlen;
162                 }
163
164                 mem_off += tlen;
165                 mem_len -= tlen;
166                 frame_len -= tlen;
167                 remaining -= tlen;
168
169                 if (frame_len &&
170                     (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
171                         continue;
172                 if (!remaining)
173                         f_ctl |= FC_FC_END_SEQ;
174                 fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
175                                FC_TYPE_FCP, f_ctl, fh_off);
176                 error = lport->tt.seq_send(lport, cmd->seq, fp);
177                 if (error) {
178                         /* XXX For now, initiator will retry */
179                         pr_err_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         }
186         return ft_queue_status(se_cmd);
187 }
188
189 /*
190  * Receive write data frame.
191  */
192 void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
193 {
194         struct se_cmd *se_cmd = &cmd->se_cmd;
195         struct fc_seq *seq = cmd->seq;
196         struct fc_exch *ep;
197         struct fc_lport *lport;
198         struct fc_frame_header *fh;
199         struct scatterlist *sg = NULL;
200         u32 mem_off = 0;
201         u32 rel_off;
202         size_t frame_len;
203         size_t mem_len = 0;
204         size_t tlen;
205         struct page *page = NULL;
206         void *page_addr;
207         void *from;
208         void *to;
209         u32 f_ctl;
210         void *buf;
211
212         fh = fc_frame_header_get(fp);
213         if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
214                 goto drop;
215
216         /*
217          * Doesn't expect even single byte of payload. Payload
218          * is expected to be copied directly to user buffers
219          * due to DDP (Large Rx offload) feature, hence
220          * BUG_ON if BUF is non-NULL
221          */
222         buf = fc_frame_payload_get(fp, 1);
223         if (cmd->was_ddp_setup && buf) {
224                 pr_debug("%s: When DDP was setup, not expected to"
225                                  "receive frame with payload, Payload shall be"
226                                  "copied directly to buffer instead of coming "
227                                  "via. legacy receive queues\n", __func__);
228                 BUG_ON(buf);
229         }
230
231         /*
232          * If ft_cmd indicated 'ddp_setup', in that case only the last frame
233          * should come with 'TSI bit being set'. If 'TSI bit is not set and if
234          * data frame appears here, means error condition. In both the cases
235          * release the DDP context (ddp_put) and in error case, as well
236          * initiate error recovery mechanism.
237          */
238         ep = fc_seq_exch(seq);
239         if (cmd->was_ddp_setup) {
240                 BUG_ON(!ep);
241                 lport = ep->lp;
242                 BUG_ON(!lport);
243         }
244         if (cmd->was_ddp_setup && ep->xid != FC_XID_UNKNOWN) {
245                 f_ctl = ntoh24(fh->fh_f_ctl);
246                 /*
247                  * If TSI bit set in f_ctl, means last write data frame is
248                  * received successfully where payload is posted directly
249                  * to user buffer and only the last frame's header is posted
250                  * in legacy receive queue
251                  */
252                 if (f_ctl & FC_FC_SEQ_INIT) { /* TSI bit set in FC frame */
253                         cmd->write_data_len = lport->tt.ddp_done(lport,
254                                                                 ep->xid);
255                         goto last_frame;
256                 } else {
257                         /*
258                          * Updating the write_data_len may be meaningless at
259                          * this point, but just in case if required in future
260                          * for debugging or any other purpose
261                          */
262                         pr_err("%s: Received frame with TSI bit not"
263                                         " being SET, dropping the frame, "
264                                         "cmd->sg <%p>, cmd->sg_cnt <0x%x>\n",
265                                         __func__, cmd->sg, cmd->sg_cnt);
266                         cmd->write_data_len = lport->tt.ddp_done(lport,
267                                                               ep->xid);
268                         lport->tt.seq_exch_abort(cmd->seq, 0);
269                         goto drop;
270                 }
271         }
272
273         rel_off = ntohl(fh->fh_parm_offset);
274         frame_len = fr_len(fp);
275         if (frame_len <= sizeof(*fh))
276                 goto drop;
277         frame_len -= sizeof(*fh);
278         from = fc_frame_payload_get(fp, 0);
279         if (rel_off >= se_cmd->data_length)
280                 goto drop;
281         if (frame_len + rel_off > se_cmd->data_length)
282                 frame_len = se_cmd->data_length - rel_off;
283
284         /*
285          * Setup to use first mem list entry, unless no data.
286          */
287         BUG_ON(frame_len && !se_cmd->t_data_sg);
288         if (frame_len) {
289                 sg = se_cmd->t_data_sg;
290                 mem_len = sg->length;
291                 mem_off = sg->offset;
292                 page = sg_page(sg);
293         }
294
295         while (frame_len) {
296                 if (!mem_len) {
297                         sg = sg_next(sg);
298                         mem_len = sg->length;
299                         mem_off = sg->offset;
300                         page = sg_page(sg);
301                 }
302                 if (rel_off >= mem_len) {
303                         rel_off -= mem_len;
304                         mem_len = 0;
305                         continue;
306                 }
307                 mem_off += rel_off;
308                 mem_len -= rel_off;
309                 rel_off = 0;
310
311                 tlen = min(mem_len, frame_len);
312
313                 to = kmap_atomic(page + (mem_off >> PAGE_SHIFT),
314                                  KM_SOFTIRQ0);
315                 page_addr = to;
316                 to += mem_off & ~PAGE_MASK;
317                 tlen = min(tlen, (size_t)(PAGE_SIZE -
318                                           (mem_off & ~PAGE_MASK)));
319                 memcpy(to, from, tlen);
320                 kunmap_atomic(page_addr, KM_SOFTIRQ0);
321
322                 from += tlen;
323                 frame_len -= tlen;
324                 mem_off += tlen;
325                 mem_len -= tlen;
326                 cmd->write_data_len += tlen;
327         }
328 last_frame:
329         if (cmd->write_data_len == se_cmd->data_length)
330                 transport_generic_handle_data(se_cmd);
331 drop:
332         fc_frame_free(fp);
333 }