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1/* bounce buffer handling for block devices
2 *
3 * - Split from highmem.c
4 */
5
6#include <linux/mm.h>
7#include <linux/module.h>
8#include <linux/swap.h>
9#include <linux/gfp.h>
10#include <linux/bio.h>
11#include <linux/pagemap.h>
12#include <linux/mempool.h>
13#include <linux/blkdev.h>
14#include <linux/init.h>
15#include <linux/hash.h>
16#include <linux/highmem.h>
17#include <asm/tlbflush.h>
18
19#include <trace/events/block.h>
20
21#define POOL_SIZE 64
22#define ISA_POOL_SIZE 16
23
24static mempool_t *page_pool, *isa_page_pool;
25
26#ifdef CONFIG_HIGHMEM
27static __init int init_emergency_pool(void)
28{
29 struct sysinfo i;
30 si_meminfo(&i);
31 si_swapinfo(&i);
32
33 if (!i.totalhigh)
34 return 0;
35
36 page_pool = mempool_create_page_pool(POOL_SIZE, 0);
37 BUG_ON(!page_pool);
38 printk("highmem bounce pool size: %d pages\n", POOL_SIZE);
39
40 return 0;
41}
42
43__initcall(init_emergency_pool);
44
45/*
46 * highmem version, map in to vec
47 */
48static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
49{
50 unsigned long flags;
51 unsigned char *vto;
52
53 local_irq_save(flags);
54 vto = kmap_atomic(to->bv_page, KM_BOUNCE_READ);
55 memcpy(vto + to->bv_offset, vfrom, to->bv_len);
56 kunmap_atomic(vto, KM_BOUNCE_READ);
57 local_irq_restore(flags);
58}
59
60#else /* CONFIG_HIGHMEM */
61
62#define bounce_copy_vec(to, vfrom) \
63 memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
64
65#endif /* CONFIG_HIGHMEM */
66
67/*
68 * allocate pages in the DMA region for the ISA pool
69 */
70static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
71{
72 return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
73}
74
75/*
76 * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
77 * as the max address, so check if the pool has already been created.
78 */
79int init_emergency_isa_pool(void)
80{
81 if (isa_page_pool)
82 return 0;
83
84 isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
85 mempool_free_pages, (void *) 0);
86 BUG_ON(!isa_page_pool);
87
88 printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE);
89 return 0;
90}
91
92/*
93 * Simple bounce buffer support for highmem pages. Depending on the
94 * queue gfp mask set, *to may or may not be a highmem page. kmap it
95 * always, it will do the Right Thing
96 */
97static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
98{
99 unsigned char *vfrom;
100 struct bio_vec *tovec, *fromvec;
101 int i;
102
103 __bio_for_each_segment(tovec, to, i, 0) {
104 fromvec = from->bi_io_vec + i;
105
106 /*
107 * not bounced
108 */
109 if (tovec->bv_page == fromvec->bv_page)
110 continue;
111
112 /*
113 * fromvec->bv_offset and fromvec->bv_len might have been
114 * modified by the block layer, so use the original copy,
115 * bounce_copy_vec already uses tovec->bv_len
116 */
117 vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;
118
119 bounce_copy_vec(tovec, vfrom);
120 flush_dcache_page(tovec->bv_page);
121 }
122}
123
124static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
125{
126 struct bio *bio_orig = bio->bi_private;
127 struct bio_vec *bvec, *org_vec;
128 int i;
129
130 if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
131 set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
132
133 /*
134 * free up bounce indirect pages used
135 */
136 __bio_for_each_segment(bvec, bio, i, 0) {
137 org_vec = bio_orig->bi_io_vec + i;
138 if (bvec->bv_page == org_vec->bv_page)
139 continue;
140
141 dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
142 mempool_free(bvec->bv_page, pool);
143 }
144
145 bio_endio(bio_orig, err);
146 bio_put(bio);
147}
148
149static void bounce_end_io_write(struct bio *bio, int err)
150{
151 bounce_end_io(bio, page_pool, err);
152}
153
154static void bounce_end_io_write_isa(struct bio *bio, int err)
155{
156
157 bounce_end_io(bio, isa_page_pool, err);
158}
159
160static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
161{
162 struct bio *bio_orig = bio->bi_private;
163
164 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
165 copy_to_high_bio_irq(bio_orig, bio);
166
167 bounce_end_io(bio, pool, err);
168}
169
170static void bounce_end_io_read(struct bio *bio, int err)
171{
172 __bounce_end_io_read(bio, page_pool, err);
173}
174
175static void bounce_end_io_read_isa(struct bio *bio, int err)
176{
177 __bounce_end_io_read(bio, isa_page_pool, err);
178}
179
180static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
181 mempool_t *pool)
182{
183 struct page *page;
184 struct bio *bio = NULL;
185 int i, rw = bio_data_dir(*bio_orig);
186 struct bio_vec *to, *from;
187
188 bio_for_each_segment(from, *bio_orig, i) {
189 page = from->bv_page;
190
191 /*
192 * is destination page below bounce pfn?
193 */
194 if (page_to_pfn(page) <= queue_bounce_pfn(q))
195 continue;
196
197 /*
198 * irk, bounce it
199 */
200 if (!bio) {
201 unsigned int cnt = (*bio_orig)->bi_vcnt;
202
203 bio = bio_alloc(GFP_NOIO, cnt);
204 memset(bio->bi_io_vec, 0, cnt * sizeof(struct bio_vec));
205 }
206
207
208 to = bio->bi_io_vec + i;
209
210 to->bv_page = mempool_alloc(pool, q->bounce_gfp);
211 to->bv_len = from->bv_len;
212 to->bv_offset = from->bv_offset;
213 inc_zone_page_state(to->bv_page, NR_BOUNCE);
214
215 if (rw == WRITE) {
216 char *vto, *vfrom;
217
218 flush_dcache_page(from->bv_page);
219 vto = page_address(to->bv_page) + to->bv_offset;
220 vfrom = kmap(from->bv_page) + from->bv_offset;
221 memcpy(vto, vfrom, to->bv_len);
222 kunmap(from->bv_page);
223 }
224 }
225
226 /*
227 * no pages bounced
228 */
229 if (!bio)
230 return;
231
232 trace_block_bio_bounce(q, *bio_orig);
233
234 /*
235 * at least one page was bounced, fill in possible non-highmem
236 * pages
237 */
238 __bio_for_each_segment(from, *bio_orig, i, 0) {
239 to = bio_iovec_idx(bio, i);
240 if (!to->bv_page) {
241 to->bv_page = from->bv_page;
242 to->bv_len = from->bv_len;
243 to->bv_offset = from->bv_offset;
244 }
245 }
246
247 bio->bi_bdev = (*bio_orig)->bi_bdev;
248 bio->bi_flags |= (1 << BIO_BOUNCED);
249 bio->bi_sector = (*bio_orig)->bi_sector;
250 bio->bi_rw = (*bio_orig)->bi_rw;
251
252 bio->bi_vcnt = (*bio_orig)->bi_vcnt;
253 bio->bi_idx = (*bio_orig)->bi_idx;
254 bio->bi_size = (*bio_orig)->bi_size;
255
256 if (pool == page_pool) {
257 bio->bi_end_io = bounce_end_io_write;
258 if (rw == READ)
259 bio->bi_end_io = bounce_end_io_read;
260 } else {
261 bio->bi_end_io = bounce_end_io_write_isa;
262 if (rw == READ)
263 bio->bi_end_io = bounce_end_io_read_isa;
264 }
265
266 bio->bi_private = *bio_orig;
267 *bio_orig = bio;
268}
269
270void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
271{
272 mempool_t *pool;
273
274 /*
275 * Data-less bio, nothing to bounce
276 */
277 if (!bio_has_data(*bio_orig))
278 return;
279
280 /*
281 * for non-isa bounce case, just check if the bounce pfn is equal
282 * to or bigger than the highest pfn in the system -- in that case,
283 * don't waste time iterating over bio segments
284 */
285 if (!(q->bounce_gfp & GFP_DMA)) {
286 if (queue_bounce_pfn(q) >= blk_max_pfn)
287 return;
288 pool = page_pool;
289 } else {
290 BUG_ON(!isa_page_pool);
291 pool = isa_page_pool;
292 }
293
294 /*
295 * slow path
296 */
297 __blk_queue_bounce(q, bio_orig, pool);
298}
299
300EXPORT_SYMBOL(blk_queue_bounce);
1/* bounce buffer handling for block devices
2 *
3 * - Split from highmem.c
4 */
5
6#include <linux/mm.h>
7#include <linux/export.h>
8#include <linux/swap.h>
9#include <linux/gfp.h>
10#include <linux/bio.h>
11#include <linux/pagemap.h>
12#include <linux/mempool.h>
13#include <linux/blkdev.h>
14#include <linux/init.h>
15#include <linux/hash.h>
16#include <linux/highmem.h>
17#include <linux/bootmem.h>
18#include <asm/tlbflush.h>
19
20#include <trace/events/block.h>
21
22#define POOL_SIZE 64
23#define ISA_POOL_SIZE 16
24
25static mempool_t *page_pool, *isa_page_pool;
26
27#if defined(CONFIG_HIGHMEM) || defined(CONFIG_NEED_BOUNCE_POOL)
28static __init int init_emergency_pool(void)
29{
30#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
31 if (max_pfn <= max_low_pfn)
32 return 0;
33#endif
34
35 page_pool = mempool_create_page_pool(POOL_SIZE, 0);
36 BUG_ON(!page_pool);
37 printk("bounce pool size: %d pages\n", POOL_SIZE);
38
39 return 0;
40}
41
42__initcall(init_emergency_pool);
43#endif
44
45#ifdef CONFIG_HIGHMEM
46/*
47 * highmem version, map in to vec
48 */
49static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
50{
51 unsigned long flags;
52 unsigned char *vto;
53
54 local_irq_save(flags);
55 vto = kmap_atomic(to->bv_page);
56 memcpy(vto + to->bv_offset, vfrom, to->bv_len);
57 kunmap_atomic(vto);
58 local_irq_restore(flags);
59}
60
61#else /* CONFIG_HIGHMEM */
62
63#define bounce_copy_vec(to, vfrom) \
64 memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
65
66#endif /* CONFIG_HIGHMEM */
67
68/*
69 * allocate pages in the DMA region for the ISA pool
70 */
71static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
72{
73 return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
74}
75
76/*
77 * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
78 * as the max address, so check if the pool has already been created.
79 */
80int init_emergency_isa_pool(void)
81{
82 if (isa_page_pool)
83 return 0;
84
85 isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
86 mempool_free_pages, (void *) 0);
87 BUG_ON(!isa_page_pool);
88
89 printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE);
90 return 0;
91}
92
93/*
94 * Simple bounce buffer support for highmem pages. Depending on the
95 * queue gfp mask set, *to may or may not be a highmem page. kmap it
96 * always, it will do the Right Thing
97 */
98static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
99{
100 unsigned char *vfrom;
101 struct bio_vec tovec, *fromvec = from->bi_io_vec;
102 struct bvec_iter iter;
103
104 bio_for_each_segment(tovec, to, iter) {
105 if (tovec.bv_page != fromvec->bv_page) {
106 /*
107 * fromvec->bv_offset and fromvec->bv_len might have
108 * been modified by the block layer, so use the original
109 * copy, bounce_copy_vec already uses tovec->bv_len
110 */
111 vfrom = page_address(fromvec->bv_page) +
112 tovec.bv_offset;
113
114 bounce_copy_vec(&tovec, vfrom);
115 flush_dcache_page(tovec.bv_page);
116 }
117
118 fromvec++;
119 }
120}
121
122static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
123{
124 struct bio *bio_orig = bio->bi_private;
125 struct bio_vec *bvec, *org_vec;
126 int i;
127
128 if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
129 set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
130
131 /*
132 * free up bounce indirect pages used
133 */
134 bio_for_each_segment_all(bvec, bio, i) {
135 org_vec = bio_orig->bi_io_vec + i;
136 if (bvec->bv_page == org_vec->bv_page)
137 continue;
138
139 dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
140 mempool_free(bvec->bv_page, pool);
141 }
142
143 bio_endio(bio_orig, err);
144 bio_put(bio);
145}
146
147static void bounce_end_io_write(struct bio *bio, int err)
148{
149 bounce_end_io(bio, page_pool, err);
150}
151
152static void bounce_end_io_write_isa(struct bio *bio, int err)
153{
154
155 bounce_end_io(bio, isa_page_pool, err);
156}
157
158static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
159{
160 struct bio *bio_orig = bio->bi_private;
161
162 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
163 copy_to_high_bio_irq(bio_orig, bio);
164
165 bounce_end_io(bio, pool, err);
166}
167
168static void bounce_end_io_read(struct bio *bio, int err)
169{
170 __bounce_end_io_read(bio, page_pool, err);
171}
172
173static void bounce_end_io_read_isa(struct bio *bio, int err)
174{
175 __bounce_end_io_read(bio, isa_page_pool, err);
176}
177
178#ifdef CONFIG_NEED_BOUNCE_POOL
179static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
180{
181 if (bio_data_dir(bio) != WRITE)
182 return 0;
183
184 if (!bdi_cap_stable_pages_required(&q->backing_dev_info))
185 return 0;
186
187 return test_bit(BIO_SNAP_STABLE, &bio->bi_flags);
188}
189#else
190static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
191{
192 return 0;
193}
194#endif /* CONFIG_NEED_BOUNCE_POOL */
195
196static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
197 mempool_t *pool, int force)
198{
199 struct bio *bio;
200 int rw = bio_data_dir(*bio_orig);
201 struct bio_vec *to, from;
202 struct bvec_iter iter;
203 unsigned i;
204
205 if (force)
206 goto bounce;
207 bio_for_each_segment(from, *bio_orig, iter)
208 if (page_to_pfn(from.bv_page) > queue_bounce_pfn(q))
209 goto bounce;
210
211 return;
212bounce:
213 bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);
214
215 bio_for_each_segment_all(to, bio, i) {
216 struct page *page = to->bv_page;
217
218 if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force)
219 continue;
220
221 inc_zone_page_state(to->bv_page, NR_BOUNCE);
222 to->bv_page = mempool_alloc(pool, q->bounce_gfp);
223
224 if (rw == WRITE) {
225 char *vto, *vfrom;
226
227 flush_dcache_page(page);
228
229 vto = page_address(to->bv_page) + to->bv_offset;
230 vfrom = kmap_atomic(page) + to->bv_offset;
231 memcpy(vto, vfrom, to->bv_len);
232 kunmap_atomic(vfrom);
233 }
234 }
235
236 trace_block_bio_bounce(q, *bio_orig);
237
238 bio->bi_flags |= (1 << BIO_BOUNCED);
239
240 if (pool == page_pool) {
241 bio->bi_end_io = bounce_end_io_write;
242 if (rw == READ)
243 bio->bi_end_io = bounce_end_io_read;
244 } else {
245 bio->bi_end_io = bounce_end_io_write_isa;
246 if (rw == READ)
247 bio->bi_end_io = bounce_end_io_read_isa;
248 }
249
250 bio->bi_private = *bio_orig;
251 *bio_orig = bio;
252}
253
254void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
255{
256 int must_bounce;
257 mempool_t *pool;
258
259 /*
260 * Data-less bio, nothing to bounce
261 */
262 if (!bio_has_data(*bio_orig))
263 return;
264
265 must_bounce = must_snapshot_stable_pages(q, *bio_orig);
266
267 /*
268 * for non-isa bounce case, just check if the bounce pfn is equal
269 * to or bigger than the highest pfn in the system -- in that case,
270 * don't waste time iterating over bio segments
271 */
272 if (!(q->bounce_gfp & GFP_DMA)) {
273 if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce)
274 return;
275 pool = page_pool;
276 } else {
277 BUG_ON(!isa_page_pool);
278 pool = isa_page_pool;
279 }
280
281 /*
282 * slow path
283 */
284 __blk_queue_bounce(q, bio_orig, pool, must_bounce);
285}
286
287EXPORT_SYMBOL(blk_queue_bounce);