xref: /linux/crypto/async_tx/async_xor.c (revision 4f2c0a4acffbec01079c28f839422e64ddeff004)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * xor offload engine api
4  *
5  * Copyright © 2006, Intel Corporation.
6  *
7  *      Dan Williams <dan.j.williams@intel.com>
8  *
9  *      with architecture considerations by:
10  *      Neil Brown <neilb@suse.de>
11  *      Jeff Garzik <jeff@garzik.org>
12  */
13 #include <linux/kernel.h>
14 #include <linux/interrupt.h>
15 #include <linux/module.h>
16 #include <linux/mm.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/raid/xor.h>
19 #include <linux/async_tx.h>
20 
21 /* do_async_xor - dma map the pages and perform the xor with an engine */
22 static __async_inline struct dma_async_tx_descriptor *
do_async_xor(struct dma_chan * chan,struct dmaengine_unmap_data * unmap,struct async_submit_ctl * submit)23 do_async_xor(struct dma_chan *chan, struct dmaengine_unmap_data *unmap,
24 	     struct async_submit_ctl *submit)
25 {
26 	struct dma_device *dma = chan->device;
27 	struct dma_async_tx_descriptor *tx = NULL;
28 	dma_async_tx_callback cb_fn_orig = submit->cb_fn;
29 	void *cb_param_orig = submit->cb_param;
30 	enum async_tx_flags flags_orig = submit->flags;
31 	enum dma_ctrl_flags dma_flags = 0;
32 	int src_cnt = unmap->to_cnt;
33 	int xor_src_cnt;
34 	dma_addr_t dma_dest = unmap->addr[unmap->to_cnt];
35 	dma_addr_t *src_list = unmap->addr;
36 
37 	while (src_cnt) {
38 		dma_addr_t tmp;
39 
40 		submit->flags = flags_orig;
41 		xor_src_cnt = min(src_cnt, (int)dma->max_xor);
42 		/* if we are submitting additional xors, leave the chain open
43 		 * and clear the callback parameters
44 		 */
45 		if (src_cnt > xor_src_cnt) {
46 			submit->flags &= ~ASYNC_TX_ACK;
47 			submit->flags |= ASYNC_TX_FENCE;
48 			submit->cb_fn = NULL;
49 			submit->cb_param = NULL;
50 		} else {
51 			submit->cb_fn = cb_fn_orig;
52 			submit->cb_param = cb_param_orig;
53 		}
54 		if (submit->cb_fn)
55 			dma_flags |= DMA_PREP_INTERRUPT;
56 		if (submit->flags & ASYNC_TX_FENCE)
57 			dma_flags |= DMA_PREP_FENCE;
58 
59 		/* Drivers force forward progress in case they can not provide a
60 		 * descriptor
61 		 */
62 		tmp = src_list[0];
63 		if (src_list > unmap->addr)
64 			src_list[0] = dma_dest;
65 		tx = dma->device_prep_dma_xor(chan, dma_dest, src_list,
66 					      xor_src_cnt, unmap->len,
67 					      dma_flags);
68 
69 		if (unlikely(!tx))
70 			async_tx_quiesce(&submit->depend_tx);
71 
72 		/* spin wait for the preceding transactions to complete */
73 		while (unlikely(!tx)) {
74 			dma_async_issue_pending(chan);
75 			tx = dma->device_prep_dma_xor(chan, dma_dest,
76 						      src_list,
77 						      xor_src_cnt, unmap->len,
78 						      dma_flags);
79 		}
80 		src_list[0] = tmp;
81 
82 		dma_set_unmap(tx, unmap);
83 		async_tx_submit(chan, tx, submit);
84 		submit->depend_tx = tx;
85 
86 		if (src_cnt > xor_src_cnt) {
87 			/* drop completed sources */
88 			src_cnt -= xor_src_cnt;
89 			/* use the intermediate result a source */
90 			src_cnt++;
91 			src_list += xor_src_cnt - 1;
92 		} else
93 			break;
94 	}
95 
96 	return tx;
97 }
98 
99 static void
do_sync_xor_offs(struct page * dest,unsigned int offset,struct page ** src_list,unsigned int * src_offs,int src_cnt,size_t len,struct async_submit_ctl * submit)100 do_sync_xor_offs(struct page *dest, unsigned int offset,
101 		struct page **src_list, unsigned int *src_offs,
102 	    int src_cnt, size_t len, struct async_submit_ctl *submit)
103 {
104 	int i;
105 	int xor_src_cnt = 0;
106 	int src_off = 0;
107 	void *dest_buf;
108 	void **srcs;
109 
110 	if (submit->scribble)
111 		srcs = submit->scribble;
112 	else
113 		srcs = (void **) src_list;
114 
115 	/* convert to buffer pointers */
116 	for (i = 0; i < src_cnt; i++)
117 		if (src_list[i])
118 			srcs[xor_src_cnt++] = page_address(src_list[i]) +
119 				(src_offs ? src_offs[i] : offset);
120 	src_cnt = xor_src_cnt;
121 	/* set destination address */
122 	dest_buf = page_address(dest) + offset;
123 
124 	if (submit->flags & ASYNC_TX_XOR_ZERO_DST)
125 		memset(dest_buf, 0, len);
126 
127 	while (src_cnt > 0) {
128 		/* process up to 'MAX_XOR_BLOCKS' sources */
129 		xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
130 		xor_blocks(xor_src_cnt, len, dest_buf, &srcs[src_off]);
131 
132 		/* drop completed sources */
133 		src_cnt -= xor_src_cnt;
134 		src_off += xor_src_cnt;
135 	}
136 
137 	async_tx_sync_epilog(submit);
138 }
139 
140 static inline bool
dma_xor_aligned_offsets(struct dma_device * device,unsigned int offset,unsigned int * src_offs,int src_cnt,int len)141 dma_xor_aligned_offsets(struct dma_device *device, unsigned int offset,
142 		unsigned int *src_offs, int src_cnt, int len)
143 {
144 	int i;
145 
146 	if (!is_dma_xor_aligned(device, offset, 0, len))
147 		return false;
148 
149 	if (!src_offs)
150 		return true;
151 
152 	for (i = 0; i < src_cnt; i++) {
153 		if (!is_dma_xor_aligned(device, src_offs[i], 0, len))
154 			return false;
155 	}
156 	return true;
157 }
158 
159 /**
160  * async_xor_offs - attempt to xor a set of blocks with a dma engine.
161  * @dest: destination page
162  * @offset: dst offset to start transaction
163  * @src_list: array of source pages
164  * @src_offs: array of source pages offset, NULL means common src/dst offset
165  * @src_cnt: number of source pages
166  * @len: length in bytes
167  * @submit: submission / completion modifiers
168  *
169  * honored flags: ASYNC_TX_ACK, ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DST
170  *
171  * xor_blocks always uses the dest as a source so the
172  * ASYNC_TX_XOR_ZERO_DST flag must be set to not include dest data in
173  * the calculation.  The assumption with dma engines is that they only
174  * use the destination buffer as a source when it is explicitly specified
175  * in the source list.
176  *
177  * src_list note: if the dest is also a source it must be at index zero.
178  * The contents of this array will be overwritten if a scribble region
179  * is not specified.
180  */
181 struct dma_async_tx_descriptor *
async_xor_offs(struct page * dest,unsigned int offset,struct page ** src_list,unsigned int * src_offs,int src_cnt,size_t len,struct async_submit_ctl * submit)182 async_xor_offs(struct page *dest, unsigned int offset,
183 		struct page **src_list, unsigned int *src_offs,
184 		int src_cnt, size_t len, struct async_submit_ctl *submit)
185 {
186 	struct dma_chan *chan = async_tx_find_channel(submit, DMA_XOR,
187 						      &dest, 1, src_list,
188 						      src_cnt, len);
189 	struct dma_device *device = chan ? chan->device : NULL;
190 	struct dmaengine_unmap_data *unmap = NULL;
191 
192 	BUG_ON(src_cnt <= 1);
193 
194 	if (device)
195 		unmap = dmaengine_get_unmap_data(device->dev, src_cnt+1, GFP_NOWAIT);
196 
197 	if (unmap && dma_xor_aligned_offsets(device, offset,
198 				src_offs, src_cnt, len)) {
199 		struct dma_async_tx_descriptor *tx;
200 		int i, j;
201 
202 		/* run the xor asynchronously */
203 		pr_debug("%s (async): len: %zu\n", __func__, len);
204 
205 		unmap->len = len;
206 		for (i = 0, j = 0; i < src_cnt; i++) {
207 			if (!src_list[i])
208 				continue;
209 			unmap->to_cnt++;
210 			unmap->addr[j++] = dma_map_page(device->dev, src_list[i],
211 					src_offs ? src_offs[i] : offset,
212 					len, DMA_TO_DEVICE);
213 		}
214 
215 		/* map it bidirectional as it may be re-used as a source */
216 		unmap->addr[j] = dma_map_page(device->dev, dest, offset, len,
217 					      DMA_BIDIRECTIONAL);
218 		unmap->bidi_cnt = 1;
219 
220 		tx = do_async_xor(chan, unmap, submit);
221 		dmaengine_unmap_put(unmap);
222 		return tx;
223 	} else {
224 		dmaengine_unmap_put(unmap);
225 		/* run the xor synchronously */
226 		pr_debug("%s (sync): len: %zu\n", __func__, len);
227 		WARN_ONCE(chan, "%s: no space for dma address conversion\n",
228 			  __func__);
229 
230 		/* in the sync case the dest is an implied source
231 		 * (assumes the dest is the first source)
232 		 */
233 		if (submit->flags & ASYNC_TX_XOR_DROP_DST) {
234 			src_cnt--;
235 			src_list++;
236 			if (src_offs)
237 				src_offs++;
238 		}
239 
240 		/* wait for any prerequisite operations */
241 		async_tx_quiesce(&submit->depend_tx);
242 
243 		do_sync_xor_offs(dest, offset, src_list, src_offs,
244 				src_cnt, len, submit);
245 
246 		return NULL;
247 	}
248 }
249 EXPORT_SYMBOL_GPL(async_xor_offs);
250 
251 /**
252  * async_xor - attempt to xor a set of blocks with a dma engine.
253  * @dest: destination page
254  * @src_list: array of source pages
255  * @offset: common src/dst offset to start transaction
256  * @src_cnt: number of source pages
257  * @len: length in bytes
258  * @submit: submission / completion modifiers
259  *
260  * honored flags: ASYNC_TX_ACK, ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DST
261  *
262  * xor_blocks always uses the dest as a source so the
263  * ASYNC_TX_XOR_ZERO_DST flag must be set to not include dest data in
264  * the calculation.  The assumption with dma engines is that they only
265  * use the destination buffer as a source when it is explicitly specified
266  * in the source list.
267  *
268  * src_list note: if the dest is also a source it must be at index zero.
269  * The contents of this array will be overwritten if a scribble region
270  * is not specified.
271  */
272 struct dma_async_tx_descriptor *
async_xor(struct page * dest,struct page ** src_list,unsigned int offset,int src_cnt,size_t len,struct async_submit_ctl * submit)273 async_xor(struct page *dest, struct page **src_list, unsigned int offset,
274 	  int src_cnt, size_t len, struct async_submit_ctl *submit)
275 {
276 	return async_xor_offs(dest, offset, src_list, NULL,
277 			src_cnt, len, submit);
278 }
279 EXPORT_SYMBOL_GPL(async_xor);
280 
page_is_zero(struct page * p,unsigned int offset,size_t len)281 static int page_is_zero(struct page *p, unsigned int offset, size_t len)
282 {
283 	return !memchr_inv(page_address(p) + offset, 0, len);
284 }
285 
286 static inline struct dma_chan *
xor_val_chan(struct async_submit_ctl * submit,struct page * dest,struct page ** src_list,int src_cnt,size_t len)287 xor_val_chan(struct async_submit_ctl *submit, struct page *dest,
288 		 struct page **src_list, int src_cnt, size_t len)
289 {
290 	#ifdef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
291 	return NULL;
292 	#endif
293 	return async_tx_find_channel(submit, DMA_XOR_VAL, &dest, 1, src_list,
294 				     src_cnt, len);
295 }
296 
297 /**
298  * async_xor_val_offs - attempt a xor parity check with a dma engine.
299  * @dest: destination page used if the xor is performed synchronously
300  * @offset: des offset in pages to start transaction
301  * @src_list: array of source pages
302  * @src_offs: array of source pages offset, NULL means common src/det offset
303  * @src_cnt: number of source pages
304  * @len: length in bytes
305  * @result: 0 if sum == 0 else non-zero
306  * @submit: submission / completion modifiers
307  *
308  * honored flags: ASYNC_TX_ACK
309  *
310  * src_list note: if the dest is also a source it must be at index zero.
311  * The contents of this array will be overwritten if a scribble region
312  * is not specified.
313  */
314 struct dma_async_tx_descriptor *
async_xor_val_offs(struct page * dest,unsigned int offset,struct page ** src_list,unsigned int * src_offs,int src_cnt,size_t len,enum sum_check_flags * result,struct async_submit_ctl * submit)315 async_xor_val_offs(struct page *dest, unsigned int offset,
316 		struct page **src_list, unsigned int *src_offs,
317 		int src_cnt, size_t len, enum sum_check_flags *result,
318 		struct async_submit_ctl *submit)
319 {
320 	struct dma_chan *chan = xor_val_chan(submit, dest, src_list, src_cnt, len);
321 	struct dma_device *device = chan ? chan->device : NULL;
322 	struct dma_async_tx_descriptor *tx = NULL;
323 	struct dmaengine_unmap_data *unmap = NULL;
324 
325 	BUG_ON(src_cnt <= 1);
326 
327 	if (device)
328 		unmap = dmaengine_get_unmap_data(device->dev, src_cnt, GFP_NOWAIT);
329 
330 	if (unmap && src_cnt <= device->max_xor &&
331 	    dma_xor_aligned_offsets(device, offset, src_offs, src_cnt, len)) {
332 		unsigned long dma_prep_flags = 0;
333 		int i;
334 
335 		pr_debug("%s: (async) len: %zu\n", __func__, len);
336 
337 		if (submit->cb_fn)
338 			dma_prep_flags |= DMA_PREP_INTERRUPT;
339 		if (submit->flags & ASYNC_TX_FENCE)
340 			dma_prep_flags |= DMA_PREP_FENCE;
341 
342 		for (i = 0; i < src_cnt; i++) {
343 			unmap->addr[i] = dma_map_page(device->dev, src_list[i],
344 					src_offs ? src_offs[i] : offset,
345 					len, DMA_TO_DEVICE);
346 			unmap->to_cnt++;
347 		}
348 		unmap->len = len;
349 
350 		tx = device->device_prep_dma_xor_val(chan, unmap->addr, src_cnt,
351 						     len, result,
352 						     dma_prep_flags);
353 		if (unlikely(!tx)) {
354 			async_tx_quiesce(&submit->depend_tx);
355 
356 			while (!tx) {
357 				dma_async_issue_pending(chan);
358 				tx = device->device_prep_dma_xor_val(chan,
359 					unmap->addr, src_cnt, len, result,
360 					dma_prep_flags);
361 			}
362 		}
363 		dma_set_unmap(tx, unmap);
364 		async_tx_submit(chan, tx, submit);
365 	} else {
366 		enum async_tx_flags flags_orig = submit->flags;
367 
368 		pr_debug("%s: (sync) len: %zu\n", __func__, len);
369 		WARN_ONCE(device && src_cnt <= device->max_xor,
370 			  "%s: no space for dma address conversion\n",
371 			  __func__);
372 
373 		submit->flags |= ASYNC_TX_XOR_DROP_DST;
374 		submit->flags &= ~ASYNC_TX_ACK;
375 
376 		tx = async_xor_offs(dest, offset, src_list, src_offs,
377 				src_cnt, len, submit);
378 
379 		async_tx_quiesce(&tx);
380 
381 		*result = !page_is_zero(dest, offset, len) << SUM_CHECK_P;
382 
383 		async_tx_sync_epilog(submit);
384 		submit->flags = flags_orig;
385 	}
386 	dmaengine_unmap_put(unmap);
387 
388 	return tx;
389 }
390 EXPORT_SYMBOL_GPL(async_xor_val_offs);
391 
392 /**
393  * async_xor_val - attempt a xor parity check with a dma engine.
394  * @dest: destination page used if the xor is performed synchronously
395  * @src_list: array of source pages
396  * @offset: offset in pages to start transaction
397  * @src_cnt: number of source pages
398  * @len: length in bytes
399  * @result: 0 if sum == 0 else non-zero
400  * @submit: submission / completion modifiers
401  *
402  * honored flags: ASYNC_TX_ACK
403  *
404  * src_list note: if the dest is also a source it must be at index zero.
405  * The contents of this array will be overwritten if a scribble region
406  * is not specified.
407  */
408 struct dma_async_tx_descriptor *
async_xor_val(struct page * dest,struct page ** src_list,unsigned int offset,int src_cnt,size_t len,enum sum_check_flags * result,struct async_submit_ctl * submit)409 async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
410 	      int src_cnt, size_t len, enum sum_check_flags *result,
411 	      struct async_submit_ctl *submit)
412 {
413 	return async_xor_val_offs(dest, offset, src_list, NULL, src_cnt,
414 			len, result, submit);
415 }
416 EXPORT_SYMBOL_GPL(async_xor_val);
417 
418 MODULE_AUTHOR("Intel Corporation");
419 MODULE_DESCRIPTION("asynchronous xor/xor-zero-sum api");
420 MODULE_LICENSE("GPL");
421