2 * Copyright(c) 2007 Yuri Tikhonov <yur@emcraft.com>
3 * Copyright(c) 2009 Intel Corporation
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the Free
7 * Software Foundation; either version 2 of the License, or (at your option)
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 59
17 * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 * The full GNU General Public License is included in this distribution in the
20 * file called COPYING.
22 #include <linux/kernel.h>
23 #include <linux/interrupt.h>
24 #include <linux/dma-mapping.h>
25 #include <linux/raid/pq.h>
26 #include <linux/async_tx.h>
29 * scribble - space to hold throwaway P buffer for synchronous gen_syndrome
31 static struct page *scribble;
33 /* the struct page *blocks[] parameter passed to async_gen_syndrome()
34 * and async_syndrome_val() contains the 'P' destination address at
35 * blocks[disks-2] and the 'Q' destination address at blocks[disks-1]
37 * note: these are macros as they are used as lvalues
39 #define P(b, d) (b[d-2])
40 #define Q(b, d) (b[d-1])
43 * do_async_gen_syndrome - asynchronously calculate P and/or Q
45 static __async_inline struct dma_async_tx_descriptor *
46 do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks,
47 const unsigned char *scfs, unsigned int offset, int disks,
48 size_t len, dma_addr_t *dma_src,
49 struct async_submit_ctl *submit)
51 struct dma_async_tx_descriptor *tx = NULL;
52 struct dma_device *dma = chan->device;
53 enum dma_ctrl_flags dma_flags = 0;
54 enum async_tx_flags flags_orig = submit->flags;
55 dma_async_tx_callback cb_fn_orig = submit->cb_fn;
56 dma_async_tx_callback cb_param_orig = submit->cb_param;
57 int src_cnt = disks - 2;
58 unsigned char coefs[src_cnt];
59 unsigned short pq_src_cnt;
60 dma_addr_t dma_dest[2];
65 /* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */
67 dma_dest[0] = dma_map_page(dma->dev, P(blocks, disks), offset,
68 len, DMA_BIDIRECTIONAL);
70 dma_flags |= DMA_PREP_PQ_DISABLE_P;
72 dma_dest[1] = dma_map_page(dma->dev, Q(blocks, disks), offset,
73 len, DMA_BIDIRECTIONAL);
75 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
77 /* convert source addresses being careful to collapse 'empty'
78 * sources and update the coefficients accordingly
80 for (i = 0, idx = 0; i < src_cnt; i++) {
81 if (blocks[i] == NULL)
83 dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len,
91 submit->flags = flags_orig;
92 pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags));
93 /* if we are submitting additional pqs, leave the chain open,
94 * clear the callback parameters, and leave the destination
97 if (src_cnt > pq_src_cnt) {
98 submit->flags &= ~ASYNC_TX_ACK;
99 submit->flags |= ASYNC_TX_FENCE;
100 dma_flags |= DMA_COMPL_SKIP_DEST_UNMAP;
101 submit->cb_fn = NULL;
102 submit->cb_param = NULL;
104 dma_flags &= ~DMA_COMPL_SKIP_DEST_UNMAP;
105 submit->cb_fn = cb_fn_orig;
106 submit->cb_param = cb_param_orig;
108 dma_flags |= DMA_PREP_INTERRUPT;
110 if (submit->flags & ASYNC_TX_FENCE)
111 dma_flags |= DMA_PREP_FENCE;
113 /* Since we have clobbered the src_list we are committed
114 * to doing this asynchronously. Drivers force forward
115 * progress in case they can not provide a descriptor
118 tx = dma->device_prep_dma_pq(chan, dma_dest,
121 &coefs[src_off], len,
125 async_tx_quiesce(&submit->depend_tx);
126 dma_async_issue_pending(chan);
129 async_tx_submit(chan, tx, submit);
130 submit->depend_tx = tx;
132 /* drop completed sources */
133 src_cnt -= pq_src_cnt;
134 src_off += pq_src_cnt;
136 dma_flags |= DMA_PREP_CONTINUE;
143 * do_sync_gen_syndrome - synchronously calculate a raid6 syndrome
146 do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
147 size_t len, struct async_submit_ctl *submit)
152 if (submit->scribble)
153 srcs = submit->scribble;
155 srcs = (void **) blocks;
157 for (i = 0; i < disks; i++) {
158 if (blocks[i] == NULL) {
159 BUG_ON(i > disks - 3); /* P or Q can't be zero */
160 srcs[i] = (void*)raid6_empty_zero_page;
162 srcs[i] = page_address(blocks[i]) + offset;
164 raid6_call.gen_syndrome(disks, len, srcs);
165 async_tx_sync_epilog(submit);
169 * async_gen_syndrome - asynchronously calculate a raid6 syndrome
170 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
171 * @offset: common offset into each block (src and dest) to start transaction
172 * @disks: number of blocks (including missing P or Q, see below)
173 * @len: length of operation in bytes
174 * @submit: submission/completion modifiers
176 * General note: This routine assumes a field of GF(2^8) with a
177 * primitive polynomial of 0x11d and a generator of {02}.
179 * 'disks' note: callers can optionally omit either P or Q (but not
180 * both) from the calculation by setting blocks[disks-2] or
181 * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <=
182 * PAGE_SIZE as a temporary buffer of this size is used in the
183 * synchronous path. 'disks' always accounts for both destination
184 * buffers. If any source buffers (blocks[i] where i < disks - 2) are
185 * set to NULL those buffers will be replaced with the raid6_zero_page
186 * in the synchronous path and omitted in the hardware-asynchronous
189 * 'blocks' note: if submit->scribble is NULL then the contents of
190 * 'blocks' may be overwritten to perform address conversions
191 * (dma_map_page() or page_address()).
193 struct dma_async_tx_descriptor *
194 async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
195 size_t len, struct async_submit_ctl *submit)
197 int src_cnt = disks - 2;
198 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
199 &P(blocks, disks), 2,
200 blocks, src_cnt, len);
201 struct dma_device *device = chan ? chan->device : NULL;
202 dma_addr_t *dma_src = NULL;
204 BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks)));
206 if (submit->scribble)
207 dma_src = submit->scribble;
208 else if (sizeof(dma_addr_t) <= sizeof(struct page *))
209 dma_src = (dma_addr_t *) blocks;
211 if (dma_src && device &&
212 (src_cnt <= dma_maxpq(device, 0) ||
213 dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
214 is_dma_pq_aligned(device, offset, 0, len)) {
215 /* run the p+q asynchronously */
216 pr_debug("%s: (async) disks: %d len: %zu\n",
217 __func__, disks, len);
218 return do_async_gen_syndrome(chan, blocks, raid6_gfexp, offset,
219 disks, len, dma_src, submit);
222 /* run the pq synchronously */
223 pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);
225 /* wait for any prerequisite operations */
226 async_tx_quiesce(&submit->depend_tx);
228 if (!P(blocks, disks)) {
229 P(blocks, disks) = scribble;
230 BUG_ON(len + offset > PAGE_SIZE);
232 if (!Q(blocks, disks)) {
233 Q(blocks, disks) = scribble;
234 BUG_ON(len + offset > PAGE_SIZE);
236 do_sync_gen_syndrome(blocks, offset, disks, len, submit);
240 EXPORT_SYMBOL_GPL(async_gen_syndrome);
243 * async_syndrome_val - asynchronously validate a raid6 syndrome
244 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
245 * @offset: common offset into each block (src and dest) to start transaction
246 * @disks: number of blocks (including missing P or Q, see below)
247 * @len: length of operation in bytes
248 * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set
249 * @spare: temporary result buffer for the synchronous case
250 * @submit: submission / completion modifiers
252 * The same notes from async_gen_syndrome apply to the 'blocks',
253 * and 'disks' parameters of this routine. The synchronous path
254 * requires a temporary result buffer and submit->scribble to be
257 struct dma_async_tx_descriptor *
258 async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
259 size_t len, enum sum_check_flags *pqres, struct page *spare,
260 struct async_submit_ctl *submit)
262 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ_VAL,
263 NULL, 0, blocks, disks,
265 struct dma_device *device = chan ? chan->device : NULL;
266 struct dma_async_tx_descriptor *tx;
267 unsigned char coefs[disks-2];
268 enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
269 dma_addr_t *dma_src = NULL;
274 if (submit->scribble)
275 dma_src = submit->scribble;
276 else if (sizeof(dma_addr_t) <= sizeof(struct page *))
277 dma_src = (dma_addr_t *) blocks;
279 if (dma_src && device && disks <= dma_maxpq(device, 0) &&
280 is_dma_pq_aligned(device, offset, 0, len)) {
281 struct device *dev = device->dev;
282 dma_addr_t *pq = &dma_src[disks-2];
285 pr_debug("%s: (async) disks: %d len: %zu\n",
286 __func__, disks, len);
287 if (!P(blocks, disks))
288 dma_flags |= DMA_PREP_PQ_DISABLE_P;
290 pq[0] = dma_map_page(dev, P(blocks, disks),
293 if (!Q(blocks, disks))
294 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
296 pq[1] = dma_map_page(dev, Q(blocks, disks),
300 if (submit->flags & ASYNC_TX_FENCE)
301 dma_flags |= DMA_PREP_FENCE;
302 for (i = 0; i < disks-2; i++)
303 if (likely(blocks[i])) {
304 dma_src[src_cnt] = dma_map_page(dev, blocks[i],
307 coefs[src_cnt] = raid6_gfexp[i];
312 tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
319 async_tx_quiesce(&submit->depend_tx);
320 dma_async_issue_pending(chan);
322 async_tx_submit(chan, tx, submit);
326 struct page *p_src = P(blocks, disks);
327 struct page *q_src = Q(blocks, disks);
328 enum async_tx_flags flags_orig = submit->flags;
329 dma_async_tx_callback cb_fn_orig = submit->cb_fn;
330 void *scribble = submit->scribble;
331 void *cb_param_orig = submit->cb_param;
334 pr_debug("%s: (sync) disks: %d len: %zu\n",
335 __func__, disks, len);
337 /* caller must provide a temporary result buffer and
338 * allow the input parameters to be preserved
340 BUG_ON(!spare || !scribble);
342 /* wait for any prerequisite operations */
343 async_tx_quiesce(&submit->depend_tx);
345 /* recompute p and/or q into the temporary buffer and then
346 * check to see the result matches the current value
351 init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,
352 NULL, NULL, scribble);
353 tx = async_xor(spare, blocks, offset, disks-2, len, submit);
354 async_tx_quiesce(&tx);
355 p = page_address(p_src) + offset;
356 s = page_address(spare) + offset;
357 *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P;
361 P(blocks, disks) = NULL;
362 Q(blocks, disks) = spare;
363 init_async_submit(submit, 0, NULL, NULL, NULL, scribble);
364 tx = async_gen_syndrome(blocks, offset, disks, len, submit);
365 async_tx_quiesce(&tx);
366 q = page_address(q_src) + offset;
367 s = page_address(spare) + offset;
368 *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q;
371 /* restore P, Q and submit */
372 P(blocks, disks) = p_src;
373 Q(blocks, disks) = q_src;
375 submit->cb_fn = cb_fn_orig;
376 submit->cb_param = cb_param_orig;
377 submit->flags = flags_orig;
378 async_tx_sync_epilog(submit);
383 EXPORT_SYMBOL_GPL(async_syndrome_val);
385 static int __init async_pq_init(void)
387 scribble = alloc_page(GFP_KERNEL);
392 pr_err("%s: failed to allocate required spare page\n", __func__);
397 static void __exit async_pq_exit(void)
402 module_init(async_pq_init);
403 module_exit(async_pq_exit);
405 MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
406 MODULE_LICENSE("GPL");