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  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 <generated/utsrelease.h>
 32#include <linux/utsname.h>
 33#include <linux/init.h>
 34#include <linux/slab.h>
 35#include <linux/kthread.h>
 36#include <linux/types.h>
 37#include <linux/string.h>
 38#include <linux/configfs.h>
 39#include <linux/ctype.h>
 40#include <linux/hash.h>
 41#include <linux/ratelimit.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_fabric.h>
 52#include <target/target_core_configfs.h>
 53#include <target/configfs_macros.h>
 54
 55#include "tcm_fc.h"
 56
 57/*
 58 * Deliver read data back to initiator.
 59 * XXX TBD handle resource problems later.
 60 */
 61int ft_queue_data_in(struct se_cmd *se_cmd)
 62{
 63	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
 64	struct fc_frame *fp = NULL;
 65	struct fc_exch *ep;
 66	struct fc_lport *lport;
 67	struct scatterlist *sg = NULL;
 68	size_t remaining;
 69	u32 f_ctl = FC_FC_EX_CTX | FC_FC_REL_OFF;
 70	u32 mem_off = 0;
 71	u32 fh_off = 0;
 72	u32 frame_off = 0;
 73	size_t frame_len = 0;
 74	size_t mem_len = 0;
 75	size_t tlen;
 76	size_t off_in_page;
 77	struct page *page = NULL;
 78	int use_sg;
 79	int error;
 80	void *page_addr;
 81	void *from;
 82	void *to = NULL;
 83
 84	if (cmd->aborted)
 85		return 0;
 86	ep = fc_seq_exch(cmd->seq);
 87	lport = ep->lp;
 88	cmd->seq = lport->tt.seq_start_next(cmd->seq);
 89
 90	remaining = se_cmd->data_length;
 91
 92	/*
 93	 * Setup to use first mem list entry, unless no data.
 94	 */
 95	BUG_ON(remaining && !se_cmd->t_data_sg);
 96	if (remaining) {
 97		sg = se_cmd->t_data_sg;
 98		mem_len = sg->length;
 99		mem_off = sg->offset;
100		page = sg_page(sg);
101	}
102
103	/* no scatter/gather in skb for odd word length due to fc_seq_send() */
104	use_sg = !(remaining % 4);
105
106	while (remaining) {
107		if (!mem_len) {
108			sg = sg_next(sg);
109			mem_len = min((size_t)sg->length, remaining);
110			mem_off = sg->offset;
111			page = sg_page(sg);
112		}
113		if (!frame_len) {
114			/*
115			 * If lport's has capability of Large Send Offload LSO)
116			 * , then allow 'frame_len' to be as big as 'lso_max'
117			 * if indicated transfer length is >= lport->lso_max
118			 */
119			frame_len = (lport->seq_offload) ? lport->lso_max :
120							  cmd->sess->max_frame;
121			frame_len = min(frame_len, remaining);
122			fp = fc_frame_alloc(lport, use_sg ? 0 : frame_len);
123			if (!fp)
124				return -ENOMEM;
125			to = fc_frame_payload_get(fp, 0);
126			fh_off = frame_off;
127			frame_off += frame_len;
128			/*
129			 * Setup the frame's max payload which is used by base
130			 * driver to indicate HW about max frame size, so that
131			 * HW can do fragmentation appropriately based on
132			 * "gso_max_size" of underline netdev.
133			 */
134			fr_max_payload(fp) = cmd->sess->max_frame;
135		}
136		tlen = min(mem_len, frame_len);
137
138		if (use_sg) {
139			off_in_page = mem_off;
140			BUG_ON(!page);
141			get_page(page);
142			skb_fill_page_desc(fp_skb(fp),
143					   skb_shinfo(fp_skb(fp))->nr_frags,
144					   page, off_in_page, tlen);
145			fr_len(fp) += tlen;
146			fp_skb(fp)->data_len += tlen;
147			fp_skb(fp)->truesize +=
148					PAGE_SIZE << compound_order(page);
149		} else {
150			BUG_ON(!page);
151			from = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
152			page_addr = from;
153			from += mem_off & ~PAGE_MASK;
154			tlen = min(tlen, (size_t)(PAGE_SIZE -
155						(mem_off & ~PAGE_MASK)));
156			memcpy(to, from, tlen);
157			kunmap_atomic(page_addr);
158			to += tlen;
159		}
160
161		mem_off += tlen;
162		mem_len -= tlen;
163		frame_len -= tlen;
164		remaining -= tlen;
165
166		if (frame_len &&
167		    (skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN))
168			continue;
169		if (!remaining)
170			f_ctl |= FC_FC_END_SEQ;
171		fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
172			       FC_TYPE_FCP, f_ctl, fh_off);
173		error = lport->tt.seq_send(lport, cmd->seq, fp);
174		if (error) {
175			/* XXX For now, initiator will retry */
176			pr_err_ratelimited("%s: Failed to send frame %p, "
177						"xid <0x%x>, remaining %zu, "
178						"lso_max <0x%x>\n",
179						__func__, fp, ep->xid,
180						remaining, lport->lso_max);
181		}
182	}
183	return ft_queue_status(se_cmd);
184}
185
186/*
187 * Receive write data frame.
188 */
189void ft_recv_write_data(struct ft_cmd *cmd, struct fc_frame *fp)
190{
191	struct se_cmd *se_cmd = &cmd->se_cmd;
192	struct fc_seq *seq = cmd->seq;
193	struct fc_exch *ep;
194	struct fc_lport *lport;
195	struct fc_frame_header *fh;
196	struct scatterlist *sg = NULL;
197	u32 mem_off = 0;
198	u32 rel_off;
199	size_t frame_len;
200	size_t mem_len = 0;
201	size_t tlen;
202	struct page *page = NULL;
203	void *page_addr;
204	void *from;
205	void *to;
206	u32 f_ctl;
207	void *buf;
208
209	fh = fc_frame_header_get(fp);
210	if (!(ntoh24(fh->fh_f_ctl) & FC_FC_REL_OFF))
211		goto drop;
212
213	f_ctl = ntoh24(fh->fh_f_ctl);
214	ep = fc_seq_exch(seq);
215	lport = ep->lp;
216	if (cmd->was_ddp_setup) {
217		BUG_ON(!ep);
218		BUG_ON(!lport);
219		/*
220		 * Since DDP (Large Rx offload) was setup for this request,
221		 * payload is expected to be copied directly to user buffers.
222		 */
223		buf = fc_frame_payload_get(fp, 1);
224		if (buf)
225			pr_err("%s: xid 0x%x, f_ctl 0x%x, cmd->sg %p, "
226				"cmd->sg_cnt 0x%x. DDP was setup"
227				" hence not expected to receive frame with "
228				"payload, Frame will be dropped if"
229				"'Sequence Initiative' bit in f_ctl is"
230				"not set\n", __func__, ep->xid, f_ctl,
231				se_cmd->t_data_sg, se_cmd->t_data_nents);
232		/*
233		 * Invalidate HW DDP context if it was setup for respective
234		 * command. Invalidation of HW DDP context is requited in both
235		 * situation (success and error).
236		 */
237		ft_invl_hw_context(cmd);
238
239		/*
240		 * If "Sequence Initiative (TSI)" bit set in f_ctl, means last
241		 * write data frame is received successfully where payload is
242		 * posted directly to user buffer and only the last frame's
243		 * header is posted in receive queue.
244		 *
245		 * If "Sequence Initiative (TSI)" bit is not set, means error
246		 * condition w.r.t. DDP, hence drop the packet and let explict
247		 * ABORTS from other end of exchange timer trigger the recovery.
248		 */
249		if (f_ctl & FC_FC_SEQ_INIT)
250			goto last_frame;
251		else
252			goto drop;
253	}
254
255	rel_off = ntohl(fh->fh_parm_offset);
256	frame_len = fr_len(fp);
257	if (frame_len <= sizeof(*fh))
258		goto drop;
259	frame_len -= sizeof(*fh);
260	from = fc_frame_payload_get(fp, 0);
261	if (rel_off >= se_cmd->data_length)
262		goto drop;
263	if (frame_len + rel_off > se_cmd->data_length)
264		frame_len = se_cmd->data_length - rel_off;
265
266	/*
267	 * Setup to use first mem list entry, unless no data.
268	 */
269	BUG_ON(frame_len && !se_cmd->t_data_sg);
270	if (frame_len) {
271		sg = se_cmd->t_data_sg;
272		mem_len = sg->length;
273		mem_off = sg->offset;
274		page = sg_page(sg);
275	}
276
277	while (frame_len) {
278		if (!mem_len) {
279			sg = sg_next(sg);
280			mem_len = sg->length;
281			mem_off = sg->offset;
282			page = sg_page(sg);
283		}
284		if (rel_off >= mem_len) {
285			rel_off -= mem_len;
286			mem_len = 0;
287			continue;
288		}
289		mem_off += rel_off;
290		mem_len -= rel_off;
291		rel_off = 0;
292
293		tlen = min(mem_len, frame_len);
294
295		to = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
296		page_addr = to;
297		to += mem_off & ~PAGE_MASK;
298		tlen = min(tlen, (size_t)(PAGE_SIZE -
299					  (mem_off & ~PAGE_MASK)));
300		memcpy(to, from, tlen);
301		kunmap_atomic(page_addr);
302
303		from += tlen;
304		frame_len -= tlen;
305		mem_off += tlen;
306		mem_len -= tlen;
307		cmd->write_data_len += tlen;
308	}
309last_frame:
310	if (cmd->write_data_len == se_cmd->data_length)
311		transport_generic_handle_data(se_cmd);
312drop:
313	fc_frame_free(fp);
314}
315
316/*
317 * Handle and cleanup any HW specific resources if
318 * received ABORTS, errors, timeouts.
319 */
320void ft_invl_hw_context(struct ft_cmd *cmd)
321{
322	struct fc_seq *seq = cmd->seq;
323	struct fc_exch *ep = NULL;
324	struct fc_lport *lport = NULL;
325
326	BUG_ON(!cmd);
327
328	/* Cleanup the DDP context in HW if DDP was setup */
329	if (cmd->was_ddp_setup && seq) {
330		ep = fc_seq_exch(seq);
331		if (ep) {
332			lport = ep->lp;
333			if (lport && (ep->xid <= lport->lro_xid))
334				/*
335				 * "ddp_done" trigger invalidation of HW
336				 * specific DDP context
337				 */
338				cmd->write_data_len = lport->tt.ddp_done(lport,
339								      ep->xid);
340
341				/*
342				 * Resetting same variable to indicate HW's
343				 * DDP context has been invalidated to avoid
344				 * re_invalidation of same context (context is
345				 * identified using ep->xid)
346				 */
347				cmd->was_ddp_setup = 0;
348		}
349	}
350}