1/*
2 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses.  You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the BSD-type
8 * license below:
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 *
14 *      Redistributions of source code must retain the above copyright
15 *      notice, this list of conditions and the following disclaimer.
16 *
17 *      Redistributions in binary form must reproduce the above
18 *      copyright notice, this list of conditions and the following
19 *      disclaimer in the documentation and/or other materials provided
20 *      with the distribution.
21 *
22 *      Neither the name of the Network Appliance, Inc. nor the names of
23 *      its contributors may be used to endorse or promote products
24 *      derived from this software without specific prior written
25 *      permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 */
39
40/*
41 * rpc_rdma.c
42 *
43 * This file contains the guts of the RPC RDMA protocol, and
44 * does marshaling/unmarshaling, etc. It is also where interfacing
45 * to the Linux RPC framework lives.
46 */
47
48#include "xprt_rdma.h"
49
50#include <linux/highmem.h>
51
52#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
53# define RPCDBG_FACILITY	RPCDBG_TRANS
54#endif
55
56enum rpcrdma_chunktype {
57	rpcrdma_noch = 0,
58	rpcrdma_readch,
59	rpcrdma_areadch,
60	rpcrdma_writech,
61	rpcrdma_replych
62};
63
64#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
65static const char transfertypes[][12] = {
66	"pure inline",	/* no chunks */
67	" read chunk",	/* some argument via rdma read */
68	"*read chunk",	/* entire request via rdma read */
69	"write chunk",	/* some result via rdma write */
70	"reply chunk"	/* entire reply via rdma write */
71};
72#endif
73
74/*
75 * Chunk assembly from upper layer xdr_buf.
76 *
77 * Prepare the passed-in xdr_buf into representation as RPC/RDMA chunk
78 * elements. Segments are then coalesced when registered, if possible
79 * within the selected memreg mode.
80 *
81 * Returns positive number of segments converted, or a negative errno.
82 */
83
84static int
85rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos,
86	enum rpcrdma_chunktype type, struct rpcrdma_mr_seg *seg, int nsegs)
87{
88	int len, n = 0, p;
89	int page_base;
90	struct page **ppages;
91
92	if (pos == 0 && xdrbuf->head[0].iov_len) {
93		seg[n].mr_page = NULL;
94		seg[n].mr_offset = xdrbuf->head[0].iov_base;
95		seg[n].mr_len = xdrbuf->head[0].iov_len;
96		++n;
97	}
98
99	len = xdrbuf->page_len;
100	ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT);
101	page_base = xdrbuf->page_base & ~PAGE_MASK;
102	p = 0;
103	while (len && n < nsegs) {
104		if (!ppages[p]) {
105			/* alloc the pagelist for receiving buffer */
106			ppages[p] = alloc_page(GFP_ATOMIC);
107			if (!ppages[p])
108				return -ENOMEM;
109		}
110		seg[n].mr_page = ppages[p];
111		seg[n].mr_offset = (void *)(unsigned long) page_base;
112		seg[n].mr_len = min_t(u32, PAGE_SIZE - page_base, len);
113		if (seg[n].mr_len > PAGE_SIZE)
114			return -EIO;
115		len -= seg[n].mr_len;
116		++n;
117		++p;
118		page_base = 0;	/* page offset only applies to first page */
119	}
120
121	/* Message overflows the seg array */
122	if (len && n == nsegs)
123		return -EIO;
124
125	if (xdrbuf->tail[0].iov_len) {
126		/* the rpcrdma protocol allows us to omit any trailing
127		 * xdr pad bytes, saving the server an RDMA operation. */
128		if (xdrbuf->tail[0].iov_len < 4 && xprt_rdma_pad_optimize)
129			return n;
130		if (n == nsegs)
131			/* Tail remains, but we're out of segments */
132			return -EIO;
133		seg[n].mr_page = NULL;
134		seg[n].mr_offset = xdrbuf->tail[0].iov_base;
135		seg[n].mr_len = xdrbuf->tail[0].iov_len;
136		++n;
137	}
138
139	return n;
140}
141
142/*
143 * Create read/write chunk lists, and reply chunks, for RDMA
144 *
145 *   Assume check against THRESHOLD has been done, and chunks are required.
146 *   Assume only encoding one list entry for read|write chunks. The NFSv3
147 *     protocol is simple enough to allow this as it only has a single "bulk
148 *     result" in each procedure - complicated NFSv4 COMPOUNDs are not. (The
149 *     RDMA/Sessions NFSv4 proposal addresses this for future v4 revs.)
150 *
151 * When used for a single reply chunk (which is a special write
152 * chunk used for the entire reply, rather than just the data), it
153 * is used primarily for READDIR and READLINK which would otherwise
154 * be severely size-limited by a small rdma inline read max. The server
155 * response will come back as an RDMA Write, followed by a message
156 * of type RDMA_NOMSG carrying the xid and length. As a result, reply
157 * chunks do not provide data alignment, however they do not require
158 * "fixup" (moving the response to the upper layer buffer) either.
159 *
160 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
161 *
162 *  Read chunklist (a linked list):
163 *   N elements, position P (same P for all chunks of same arg!):
164 *    1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
165 *
166 *  Write chunklist (a list of (one) counted array):
167 *   N elements:
168 *    1 - N - HLOO - HLOO - ... - HLOO - 0
169 *
170 *  Reply chunk (a counted array):
171 *   N elements:
172 *    1 - N - HLOO - HLOO - ... - HLOO
173 *
174 * Returns positive RPC/RDMA header size, or negative errno.
175 */
176
177static ssize_t
178rpcrdma_create_chunks(struct rpc_rqst *rqst, struct xdr_buf *target,
179		struct rpcrdma_msg *headerp, enum rpcrdma_chunktype type)
180{
181	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
182	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
183	int n, nsegs, nchunks = 0;
184	unsigned int pos;
185	struct rpcrdma_mr_seg *seg = req->rl_segments;
186	struct rpcrdma_read_chunk *cur_rchunk = NULL;
187	struct rpcrdma_write_array *warray = NULL;
188	struct rpcrdma_write_chunk *cur_wchunk = NULL;
189	__be32 *iptr = headerp->rm_body.rm_chunks;
190	int (*map)(struct rpcrdma_xprt *, struct rpcrdma_mr_seg *, int, bool);
191
192	if (type == rpcrdma_readch || type == rpcrdma_areadch) {
193		/* a read chunk - server will RDMA Read our memory */
194		cur_rchunk = (struct rpcrdma_read_chunk *) iptr;
195	} else {
196		/* a write or reply chunk - server will RDMA Write our memory */
197		*iptr++ = xdr_zero;	/* encode a NULL read chunk list */
198		if (type == rpcrdma_replych)
199			*iptr++ = xdr_zero;	/* a NULL write chunk list */
200		warray = (struct rpcrdma_write_array *) iptr;
201		cur_wchunk = (struct rpcrdma_write_chunk *) (warray + 1);
202	}
203
204	if (type == rpcrdma_replych || type == rpcrdma_areadch)
205		pos = 0;
206	else
207		pos = target->head[0].iov_len;
208
209	nsegs = rpcrdma_convert_iovs(target, pos, type, seg, RPCRDMA_MAX_SEGS);
210	if (nsegs < 0)
211		return nsegs;
212
213	map = r_xprt->rx_ia.ri_ops->ro_map;
214	do {
215		n = map(r_xprt, seg, nsegs, cur_wchunk != NULL);
216		if (n <= 0)
217			goto out;
218		if (cur_rchunk) {	/* read */
219			cur_rchunk->rc_discrim = xdr_one;
220			/* all read chunks have the same "position" */
221			cur_rchunk->rc_position = cpu_to_be32(pos);
222			cur_rchunk->rc_target.rs_handle =
223						cpu_to_be32(seg->mr_rkey);
224			cur_rchunk->rc_target.rs_length =
225						cpu_to_be32(seg->mr_len);
226			xdr_encode_hyper(
227					(__be32 *)&cur_rchunk->rc_target.rs_offset,
228					seg->mr_base);
229			dprintk("RPC:       %s: read chunk "
230				"elem %d@0x%llx:0x%x pos %u (%s)\n", __func__,
231				seg->mr_len, (unsigned long long)seg->mr_base,
232				seg->mr_rkey, pos, n < nsegs ? "more" : "last");
233			cur_rchunk++;
234			r_xprt->rx_stats.read_chunk_count++;
235		} else {		/* write/reply */
236			cur_wchunk->wc_target.rs_handle =
237						cpu_to_be32(seg->mr_rkey);
238			cur_wchunk->wc_target.rs_length =
239						cpu_to_be32(seg->mr_len);
240			xdr_encode_hyper(
241					(__be32 *)&cur_wchunk->wc_target.rs_offset,
242					seg->mr_base);
243			dprintk("RPC:       %s: %s chunk "
244				"elem %d@0x%llx:0x%x (%s)\n", __func__,
245				(type == rpcrdma_replych) ? "reply" : "write",
246				seg->mr_len, (unsigned long long)seg->mr_base,
247				seg->mr_rkey, n < nsegs ? "more" : "last");
248			cur_wchunk++;
249			if (type == rpcrdma_replych)
250				r_xprt->rx_stats.reply_chunk_count++;
251			else
252				r_xprt->rx_stats.write_chunk_count++;
253			r_xprt->rx_stats.total_rdma_request += seg->mr_len;
254		}
255		nchunks++;
256		seg   += n;
257		nsegs -= n;
258	} while (nsegs);
259
260	/* success. all failures return above */
261	req->rl_nchunks = nchunks;
262
263	/*
264	 * finish off header. If write, marshal discrim and nchunks.
265	 */
266	if (cur_rchunk) {
267		iptr = (__be32 *) cur_rchunk;
268		*iptr++ = xdr_zero;	/* finish the read chunk list */
269		*iptr++ = xdr_zero;	/* encode a NULL write chunk list */
270		*iptr++ = xdr_zero;	/* encode a NULL reply chunk */
271	} else {
272		warray->wc_discrim = xdr_one;
273		warray->wc_nchunks = cpu_to_be32(nchunks);
274		iptr = (__be32 *) cur_wchunk;
275		if (type == rpcrdma_writech) {
276			*iptr++ = xdr_zero; /* finish the write chunk list */
277			*iptr++ = xdr_zero; /* encode a NULL reply chunk */
278		}
279	}
280
281	/*
282	 * Return header size.
283	 */
284	return (unsigned char *)iptr - (unsigned char *)headerp;
285
286out:
287	if (r_xprt->rx_ia.ri_memreg_strategy == RPCRDMA_FRMR)
288		return n;
289
290	for (pos = 0; nchunks--;)
291		pos += r_xprt->rx_ia.ri_ops->ro_unmap(r_xprt,
292						      &req->rl_segments[pos]);
293	return n;
294}
295
296/*
297 * Copy write data inline.
298 * This function is used for "small" requests. Data which is passed
299 * to RPC via iovecs (or page list) is copied directly into the
300 * pre-registered memory buffer for this request. For small amounts
301 * of data, this is efficient. The cutoff value is tunable.
302 */
303static int
304rpcrdma_inline_pullup(struct rpc_rqst *rqst, int pad)
305{
306	int i, npages, curlen;
307	int copy_len;
308	unsigned char *srcp, *destp;
309	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
310	int page_base;
311	struct page **ppages;
312
313	destp = rqst->rq_svec[0].iov_base;
314	curlen = rqst->rq_svec[0].iov_len;
315	destp += curlen;
316	/*
317	 * Do optional padding where it makes sense. Alignment of write
318	 * payload can help the server, if our setting is accurate.
319	 */
320	pad -= (curlen + 36/*sizeof(struct rpcrdma_msg_padded)*/);
321	if (pad < 0 || rqst->rq_slen - curlen < RPCRDMA_INLINE_PAD_THRESH)
322		pad = 0;	/* don't pad this request */
323
324	dprintk("RPC:       %s: pad %d destp 0x%p len %d hdrlen %d\n",
325		__func__, pad, destp, rqst->rq_slen, curlen);
326
327	copy_len = rqst->rq_snd_buf.page_len;
328
329	if (rqst->rq_snd_buf.tail[0].iov_len) {
330		curlen = rqst->rq_snd_buf.tail[0].iov_len;
331		if (destp + copy_len != rqst->rq_snd_buf.tail[0].iov_base) {
332			memmove(destp + copy_len,
333				rqst->rq_snd_buf.tail[0].iov_base, curlen);
334			r_xprt->rx_stats.pullup_copy_count += curlen;
335		}
336		dprintk("RPC:       %s: tail destp 0x%p len %d\n",
337			__func__, destp + copy_len, curlen);
338		rqst->rq_svec[0].iov_len += curlen;
339	}
340	r_xprt->rx_stats.pullup_copy_count += copy_len;
341
342	page_base = rqst->rq_snd_buf.page_base;
343	ppages = rqst->rq_snd_buf.pages + (page_base >> PAGE_SHIFT);
344	page_base &= ~PAGE_MASK;
345	npages = PAGE_ALIGN(page_base+copy_len) >> PAGE_SHIFT;
346	for (i = 0; copy_len && i < npages; i++) {
347		curlen = PAGE_SIZE - page_base;
348		if (curlen > copy_len)
349			curlen = copy_len;
350		dprintk("RPC:       %s: page %d destp 0x%p len %d curlen %d\n",
351			__func__, i, destp, copy_len, curlen);
352		srcp = kmap_atomic(ppages[i]);
353		memcpy(destp, srcp+page_base, curlen);
354		kunmap_atomic(srcp);
355		rqst->rq_svec[0].iov_len += curlen;
356		destp += curlen;
357		copy_len -= curlen;
358		page_base = 0;
359	}
360	/* header now contains entire send message */
361	return pad;
362}
363
364/*
365 * Marshal a request: the primary job of this routine is to choose
366 * the transfer modes. See comments below.
367 *
368 * Uses multiple RDMA IOVs for a request:
369 *  [0] -- RPC RDMA header, which uses memory from the *start* of the
370 *         preregistered buffer that already holds the RPC data in
371 *         its middle.
372 *  [1] -- the RPC header/data, marshaled by RPC and the NFS protocol.
373 *  [2] -- optional padding.
374 *  [3] -- if padded, header only in [1] and data here.
375 *
376 * Returns zero on success, otherwise a negative errno.
377 */
378
379int
380rpcrdma_marshal_req(struct rpc_rqst *rqst)
381{
382	struct rpc_xprt *xprt = rqst->rq_xprt;
383	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
384	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
385	char *base;
386	size_t rpclen, padlen;
387	ssize_t hdrlen;
388	enum rpcrdma_chunktype rtype, wtype;
389	struct rpcrdma_msg *headerp;
390
391	/*
392	 * rpclen gets amount of data in first buffer, which is the
393	 * pre-registered buffer.
394	 */
395	base = rqst->rq_svec[0].iov_base;
396	rpclen = rqst->rq_svec[0].iov_len;
397
398	headerp = rdmab_to_msg(req->rl_rdmabuf);
399	/* don't byte-swap XID, it's already done in request */
400	headerp->rm_xid = rqst->rq_xid;
401	headerp->rm_vers = rpcrdma_version;
402	headerp->rm_credit = cpu_to_be32(r_xprt->rx_buf.rb_max_requests);
403	headerp->rm_type = rdma_msg;
404
405	/*
406	 * Chunks needed for results?
407	 *
408	 * o If the expected result is under the inline threshold, all ops
409	 *   return as inline (but see later).
410	 * o Large non-read ops return as a single reply chunk.
411	 * o Large read ops return data as write chunk(s), header as inline.
412	 *
413	 * Note: the NFS code sending down multiple result segments implies
414	 * the op is one of read, readdir[plus], readlink or NFSv4 getacl.
415	 */
416
417	/*
418	 * This code can handle read chunks, write chunks OR reply
419	 * chunks -- only one type. If the request is too big to fit
420	 * inline, then we will choose read chunks. If the request is
421	 * a READ, then use write chunks to separate the file data
422	 * into pages; otherwise use reply chunks.
423	 */
424	if (rqst->rq_rcv_buf.buflen <= RPCRDMA_INLINE_READ_THRESHOLD(rqst))
425		wtype = rpcrdma_noch;
426	else if (rqst->rq_rcv_buf.page_len == 0)
427		wtype = rpcrdma_replych;
428	else if (rqst->rq_rcv_buf.flags & XDRBUF_READ)
429		wtype = rpcrdma_writech;
430	else
431		wtype = rpcrdma_replych;
432
433	/*
434	 * Chunks needed for arguments?
435	 *
436	 * o If the total request is under the inline threshold, all ops
437	 *   are sent as inline.
438	 * o Large non-write ops are sent with the entire message as a
439	 *   single read chunk (protocol 0-position special case).
440	 * o Large write ops transmit data as read chunk(s), header as
441	 *   inline.
442	 *
443	 * Note: the NFS code sending down multiple argument segments
444	 * implies the op is a write.
445	 * TBD check NFSv4 setacl
446	 */
447	if (rqst->rq_snd_buf.len <= RPCRDMA_INLINE_WRITE_THRESHOLD(rqst))
448		rtype = rpcrdma_noch;
449	else if (rqst->rq_snd_buf.page_len == 0)
450		rtype = rpcrdma_areadch;
451	else
452		rtype = rpcrdma_readch;
453
454	/* The following simplification is not true forever */
455	if (rtype != rpcrdma_noch && wtype == rpcrdma_replych)
456		wtype = rpcrdma_noch;
457	if (rtype != rpcrdma_noch && wtype != rpcrdma_noch) {
458		dprintk("RPC:       %s: cannot marshal multiple chunk lists\n",
459			__func__);
460		return -EIO;
461	}
462
463	hdrlen = RPCRDMA_HDRLEN_MIN;
464	padlen = 0;
465
466	/*
467	 * Pull up any extra send data into the preregistered buffer.
468	 * When padding is in use and applies to the transfer, insert
469	 * it and change the message type.
470	 */
471	if (rtype == rpcrdma_noch) {
472
473		padlen = rpcrdma_inline_pullup(rqst,
474						RPCRDMA_INLINE_PAD_VALUE(rqst));
475
476		if (padlen) {
477			headerp->rm_type = rdma_msgp;
478			headerp->rm_body.rm_padded.rm_align =
479				cpu_to_be32(RPCRDMA_INLINE_PAD_VALUE(rqst));
480			headerp->rm_body.rm_padded.rm_thresh =
481				cpu_to_be32(RPCRDMA_INLINE_PAD_THRESH);
482			headerp->rm_body.rm_padded.rm_pempty[0] = xdr_zero;
483			headerp->rm_body.rm_padded.rm_pempty[1] = xdr_zero;
484			headerp->rm_body.rm_padded.rm_pempty[2] = xdr_zero;
485			hdrlen += 2 * sizeof(u32); /* extra words in padhdr */
486			if (wtype != rpcrdma_noch) {
487				dprintk("RPC:       %s: invalid chunk list\n",
488					__func__);
489				return -EIO;
490			}
491		} else {
492			headerp->rm_body.rm_nochunks.rm_empty[0] = xdr_zero;
493			headerp->rm_body.rm_nochunks.rm_empty[1] = xdr_zero;
494			headerp->rm_body.rm_nochunks.rm_empty[2] = xdr_zero;
495			/* new length after pullup */
496			rpclen = rqst->rq_svec[0].iov_len;
497			/*
498			 * Currently we try to not actually use read inline.
499			 * Reply chunks have the desirable property that
500			 * they land, packed, directly in the target buffers
501			 * without headers, so they require no fixup. The
502			 * additional RDMA Write op sends the same amount
503			 * of data, streams on-the-wire and adds no overhead
504			 * on receive. Therefore, we request a reply chunk
505			 * for non-writes wherever feasible and efficient.
506			 */
507			if (wtype == rpcrdma_noch)
508				wtype = rpcrdma_replych;
509		}
510	}
511
512	if (rtype != rpcrdma_noch) {
513		hdrlen = rpcrdma_create_chunks(rqst, &rqst->rq_snd_buf,
514					       headerp, rtype);
515		wtype = rtype;	/* simplify dprintk */
516
517	} else if (wtype != rpcrdma_noch) {
518		hdrlen = rpcrdma_create_chunks(rqst, &rqst->rq_rcv_buf,
519					       headerp, wtype);
520	}
521	if (hdrlen < 0)
522		return hdrlen;
523
524	dprintk("RPC:       %s: %s: hdrlen %zd rpclen %zd padlen %zd"
525		" headerp 0x%p base 0x%p lkey 0x%x\n",
526		__func__, transfertypes[wtype], hdrlen, rpclen, padlen,
527		headerp, base, rdmab_lkey(req->rl_rdmabuf));
528
529	/*
530	 * initialize send_iov's - normally only two: rdma chunk header and
531	 * single preregistered RPC header buffer, but if padding is present,
532	 * then use a preregistered (and zeroed) pad buffer between the RPC
533	 * header and any write data. In all non-rdma cases, any following
534	 * data has been copied into the RPC header buffer.
535	 */
536	req->rl_send_iov[0].addr = rdmab_addr(req->rl_rdmabuf);
537	req->rl_send_iov[0].length = hdrlen;
538	req->rl_send_iov[0].lkey = rdmab_lkey(req->rl_rdmabuf);
539
540	req->rl_send_iov[1].addr = rdmab_addr(req->rl_sendbuf);
541	req->rl_send_iov[1].length = rpclen;
542	req->rl_send_iov[1].lkey = rdmab_lkey(req->rl_sendbuf);
543
544	req->rl_niovs = 2;
545
546	if (padlen) {
547		struct rpcrdma_ep *ep = &r_xprt->rx_ep;
548
549		req->rl_send_iov[2].addr = rdmab_addr(ep->rep_padbuf);
550		req->rl_send_iov[2].length = padlen;
551		req->rl_send_iov[2].lkey = rdmab_lkey(ep->rep_padbuf);
552
553		req->rl_send_iov[3].addr = req->rl_send_iov[1].addr + rpclen;
554		req->rl_send_iov[3].length = rqst->rq_slen - rpclen;
555		req->rl_send_iov[3].lkey = rdmab_lkey(req->rl_sendbuf);
556
557		req->rl_niovs = 4;
558	}
559
560	return 0;
561}
562
563/*
564 * Chase down a received write or reply chunklist to get length
565 * RDMA'd by server. See map at rpcrdma_create_chunks()! :-)
566 */
567static int
568rpcrdma_count_chunks(struct rpcrdma_rep *rep, unsigned int max, int wrchunk, __be32 **iptrp)
569{
570	unsigned int i, total_len;
571	struct rpcrdma_write_chunk *cur_wchunk;
572	char *base = (char *)rdmab_to_msg(rep->rr_rdmabuf);
573
574	i = be32_to_cpu(**iptrp);
575	if (i > max)
576		return -1;
577	cur_wchunk = (struct rpcrdma_write_chunk *) (*iptrp + 1);
578	total_len = 0;
579	while (i--) {
580		struct rpcrdma_segment *seg = &cur_wchunk->wc_target;
581		ifdebug(FACILITY) {
582			u64 off;
583			xdr_decode_hyper((__be32 *)&seg->rs_offset, &off);
584			dprintk("RPC:       %s: chunk %d@0x%llx:0x%x\n",
585				__func__,
586				be32_to_cpu(seg->rs_length),
587				(unsigned long long)off,
588				be32_to_cpu(seg->rs_handle));
589		}
590		total_len += be32_to_cpu(seg->rs_length);
591		++cur_wchunk;
592	}
593	/* check and adjust for properly terminated write chunk */
594	if (wrchunk) {
595		__be32 *w = (__be32 *) cur_wchunk;
596		if (*w++ != xdr_zero)
597			return -1;
598		cur_wchunk = (struct rpcrdma_write_chunk *) w;
599	}
600	if ((char *)cur_wchunk > base + rep->rr_len)
601		return -1;
602
603	*iptrp = (__be32 *) cur_wchunk;
604	return total_len;
605}
606
607/*
608 * Scatter inline received data back into provided iov's.
609 */
610static void
611rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
612{
613	int i, npages, curlen, olen;
614	char *destp;
615	struct page **ppages;
616	int page_base;
617
618	curlen = rqst->rq_rcv_buf.head[0].iov_len;
619	if (curlen > copy_len) {	/* write chunk header fixup */
620		curlen = copy_len;
621		rqst->rq_rcv_buf.head[0].iov_len = curlen;
622	}
623
624	dprintk("RPC:       %s: srcp 0x%p len %d hdrlen %d\n",
625		__func__, srcp, copy_len, curlen);
626
627	/* Shift pointer for first receive segment only */
628	rqst->rq_rcv_buf.head[0].iov_base = srcp;
629	srcp += curlen;
630	copy_len -= curlen;
631
632	olen = copy_len;
633	i = 0;
634	rpcx_to_rdmax(rqst->rq_xprt)->rx_stats.fixup_copy_count += olen;
635	page_base = rqst->rq_rcv_buf.page_base;
636	ppages = rqst->rq_rcv_buf.pages + (page_base >> PAGE_SHIFT);
637	page_base &= ~PAGE_MASK;
638
639	if (copy_len && rqst->rq_rcv_buf.page_len) {
640		npages = PAGE_ALIGN(page_base +
641			rqst->rq_rcv_buf.page_len) >> PAGE_SHIFT;
642		for (; i < npages; i++) {
643			curlen = PAGE_SIZE - page_base;
644			if (curlen > copy_len)
645				curlen = copy_len;
646			dprintk("RPC:       %s: page %d"
647				" srcp 0x%p len %d curlen %d\n",
648				__func__, i, srcp, copy_len, curlen);
649			destp = kmap_atomic(ppages[i]);
650			memcpy(destp + page_base, srcp, curlen);
651			flush_dcache_page(ppages[i]);
652			kunmap_atomic(destp);
653			srcp += curlen;
654			copy_len -= curlen;
655			if (copy_len == 0)
656				break;
657			page_base = 0;
658		}
659	}
660
661	if (copy_len && rqst->rq_rcv_buf.tail[0].iov_len) {
662		curlen = copy_len;
663		if (curlen > rqst->rq_rcv_buf.tail[0].iov_len)
664			curlen = rqst->rq_rcv_buf.tail[0].iov_len;
665		if (rqst->rq_rcv_buf.tail[0].iov_base != srcp)
666			memmove(rqst->rq_rcv_buf.tail[0].iov_base, srcp, curlen);
667		dprintk("RPC:       %s: tail srcp 0x%p len %d curlen %d\n",
668			__func__, srcp, copy_len, curlen);
669		rqst->rq_rcv_buf.tail[0].iov_len = curlen;
670		copy_len -= curlen; ++i;
671	} else
672		rqst->rq_rcv_buf.tail[0].iov_len = 0;
673
674	if (pad) {
675		/* implicit padding on terminal chunk */
676		unsigned char *p = rqst->rq_rcv_buf.tail[0].iov_base;
677		while (pad--)
678			p[rqst->rq_rcv_buf.tail[0].iov_len++] = 0;
679	}
680
681	if (copy_len)
682		dprintk("RPC:       %s: %d bytes in"
683			" %d extra segments (%d lost)\n",
684			__func__, olen, i, copy_len);
685
686	/* TBD avoid a warning from call_decode() */
687	rqst->rq_private_buf = rqst->rq_rcv_buf;
688}
689
690void
691rpcrdma_connect_worker(struct work_struct *work)
692{
693	struct rpcrdma_ep *ep =
694		container_of(work, struct rpcrdma_ep, rep_connect_worker.work);
695	struct rpcrdma_xprt *r_xprt =
696		container_of(ep, struct rpcrdma_xprt, rx_ep);
697	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
698
699	spin_lock_bh(&xprt->transport_lock);
700	if (++xprt->connect_cookie == 0)	/* maintain a reserved value */
701		++xprt->connect_cookie;
702	if (ep->rep_connected > 0) {
703		if (!xprt_test_and_set_connected(xprt))
704			xprt_wake_pending_tasks(xprt, 0);
705	} else {
706		if (xprt_test_and_clear_connected(xprt))
707			xprt_wake_pending_tasks(xprt, -ENOTCONN);
708	}
709	spin_unlock_bh(&xprt->transport_lock);
710}
711
712/*
713 * This function is called when an async event is posted to
714 * the connection which changes the connection state. All it
715 * does at this point is mark the connection up/down, the rpc
716 * timers do the rest.
717 */
718void
719rpcrdma_conn_func(struct rpcrdma_ep *ep)
720{
721	schedule_delayed_work(&ep->rep_connect_worker, 0);
722}
723
724/*
725 * Called as a tasklet to do req/reply match and complete a request
726 * Errors must result in the RPC task either being awakened, or
727 * allowed to timeout, to discover the errors at that time.
728 */
729void
730rpcrdma_reply_handler(struct rpcrdma_rep *rep)
731{
732	struct rpcrdma_msg *headerp;
733	struct rpcrdma_req *req;
734	struct rpc_rqst *rqst;
735	struct rpc_xprt *xprt = rep->rr_xprt;
736	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
737	__be32 *iptr;
738	int rdmalen, status;
739	unsigned long cwnd;
740	u32 credits;
741
742	/* Check status. If bad, signal disconnect and return rep to pool */
743	if (rep->rr_len == ~0U) {
744		rpcrdma_recv_buffer_put(rep);
745		if (r_xprt->rx_ep.rep_connected == 1) {
746			r_xprt->rx_ep.rep_connected = -EIO;
747			rpcrdma_conn_func(&r_xprt->rx_ep);
748		}
749		return;
750	}
751	if (rep->rr_len < RPCRDMA_HDRLEN_MIN) {
752		dprintk("RPC:       %s: short/invalid reply\n", __func__);
753		goto repost;
754	}
755	headerp = rdmab_to_msg(rep->rr_rdmabuf);
756	if (headerp->rm_vers != rpcrdma_version) {
757		dprintk("RPC:       %s: invalid version %d\n",
758			__func__, be32_to_cpu(headerp->rm_vers));
759		goto repost;
760	}
761
762	/* Get XID and try for a match. */
763	spin_lock(&xprt->transport_lock);
764	rqst = xprt_lookup_rqst(xprt, headerp->rm_xid);
765	if (rqst == NULL) {
766		spin_unlock(&xprt->transport_lock);
767		dprintk("RPC:       %s: reply 0x%p failed "
768			"to match any request xid 0x%08x len %d\n",
769			__func__, rep, be32_to_cpu(headerp->rm_xid),
770			rep->rr_len);
771repost:
772		r_xprt->rx_stats.bad_reply_count++;
773		rep->rr_func = rpcrdma_reply_handler;
774		if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, &r_xprt->rx_ep, rep))
775			rpcrdma_recv_buffer_put(rep);
776
777		return;
778	}
779
780	/* get request object */
781	req = rpcr_to_rdmar(rqst);
782	if (req->rl_reply) {
783		spin_unlock(&xprt->transport_lock);
784		dprintk("RPC:       %s: duplicate reply 0x%p to RPC "
785			"request 0x%p: xid 0x%08x\n", __func__, rep, req,
786			be32_to_cpu(headerp->rm_xid));
787		goto repost;
788	}
789
790	dprintk("RPC:       %s: reply 0x%p completes request 0x%p\n"
791		"                   RPC request 0x%p xid 0x%08x\n",
792			__func__, rep, req, rqst,
793			be32_to_cpu(headerp->rm_xid));
794
795	/* from here on, the reply is no longer an orphan */
796	req->rl_reply = rep;
797	xprt->reestablish_timeout = 0;
798
799	/* check for expected message types */
800	/* The order of some of these tests is important. */
801	switch (headerp->rm_type) {
802	case rdma_msg:
803		/* never expect read chunks */
804		/* never expect reply chunks (two ways to check) */
805		/* never expect write chunks without having offered RDMA */
806		if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
807		    (headerp->rm_body.rm_chunks[1] == xdr_zero &&
808		     headerp->rm_body.rm_chunks[2] != xdr_zero) ||
809		    (headerp->rm_body.rm_chunks[1] != xdr_zero &&
810		     req->rl_nchunks == 0))
811			goto badheader;
812		if (headerp->rm_body.rm_chunks[1] != xdr_zero) {
813			/* count any expected write chunks in read reply */
814			/* start at write chunk array count */
815			iptr = &headerp->rm_body.rm_chunks[2];
816			rdmalen = rpcrdma_count_chunks(rep,
817						req->rl_nchunks, 1, &iptr);
818			/* check for validity, and no reply chunk after */
819			if (rdmalen < 0 || *iptr++ != xdr_zero)
820				goto badheader;
821			rep->rr_len -=
822			    ((unsigned char *)iptr - (unsigned char *)headerp);
823			status = rep->rr_len + rdmalen;
824			r_xprt->rx_stats.total_rdma_reply += rdmalen;
825			/* special case - last chunk may omit padding */
826			if (rdmalen &= 3) {
827				rdmalen = 4 - rdmalen;
828				status += rdmalen;
829			}
830		} else {
831			/* else ordinary inline */
832			rdmalen = 0;
833			iptr = (__be32 *)((unsigned char *)headerp +
834							RPCRDMA_HDRLEN_MIN);
835			rep->rr_len -= RPCRDMA_HDRLEN_MIN;
836			status = rep->rr_len;
837		}
838		/* Fix up the rpc results for upper layer */
839		rpcrdma_inline_fixup(rqst, (char *)iptr, rep->rr_len, rdmalen);
840		break;
841
842	case rdma_nomsg:
843		/* never expect read or write chunks, always reply chunks */
844		if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
845		    headerp->rm_body.rm_chunks[1] != xdr_zero ||
846		    headerp->rm_body.rm_chunks[2] != xdr_one ||
847		    req->rl_nchunks == 0)
848			goto badheader;
849		iptr = (__be32 *)((unsigned char *)headerp +
850							RPCRDMA_HDRLEN_MIN);
851		rdmalen = rpcrdma_count_chunks(rep, req->rl_nchunks, 0, &iptr);
852		if (rdmalen < 0)
853			goto badheader;
854		r_xprt->rx_stats.total_rdma_reply += rdmalen;
855		/* Reply chunk buffer already is the reply vector - no fixup. */
856		status = rdmalen;
857		break;
858
859badheader:
860	default:
861		dprintk("%s: invalid rpcrdma reply header (type %d):"
862				" chunks[012] == %d %d %d"
863				" expected chunks <= %d\n",
864				__func__, be32_to_cpu(headerp->rm_type),
865				headerp->rm_body.rm_chunks[0],
866				headerp->rm_body.rm_chunks[1],
867				headerp->rm_body.rm_chunks[2],
868				req->rl_nchunks);
869		status = -EIO;
870		r_xprt->rx_stats.bad_reply_count++;
871		break;
872	}
873
874	credits = be32_to_cpu(headerp->rm_credit);
875	if (credits == 0)
876		credits = 1;	/* don't deadlock */
877	else if (credits > r_xprt->rx_buf.rb_max_requests)
878		credits = r_xprt->rx_buf.rb_max_requests;
879
880	cwnd = xprt->cwnd;
881	xprt->cwnd = credits << RPC_CWNDSHIFT;
882	if (xprt->cwnd > cwnd)
883		xprt_release_rqst_cong(rqst->rq_task);
884
885	dprintk("RPC:       %s: xprt_complete_rqst(0x%p, 0x%p, %d)\n",
886			__func__, xprt, rqst, status);
887	xprt_complete_rqst(rqst->rq_task, status);
888	spin_unlock(&xprt->transport_lock);
889}
890