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Commit | Line | Data |
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831058de DH |
1 | /* bounce buffer handling for block devices |
2 | * | |
3 | * - Split from highmem.c | |
4 | */ | |
5 | ||
6 | #include <linux/mm.h> | |
b95f1b31 | 7 | #include <linux/export.h> |
831058de | 8 | #include <linux/swap.h> |
5a0e3ad6 | 9 | #include <linux/gfp.h> |
831058de DH |
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> | |
3bcfeaf9 | 17 | #include <linux/bootmem.h> |
831058de DH |
18 | #include <asm/tlbflush.h> |
19 | ||
55782138 LZ |
20 | #include <trace/events/block.h> |
21 | ||
831058de DH |
22 | #define POOL_SIZE 64 |
23 | #define ISA_POOL_SIZE 16 | |
24 | ||
25 | static mempool_t *page_pool, *isa_page_pool; | |
26 | ||
f1006257 | 27 | #if defined(CONFIG_HIGHMEM) || defined(CONFIG_NEED_BOUNCE_POOL) |
831058de DH |
28 | static __init int init_emergency_pool(void) |
29 | { | |
f1006257 | 30 | #if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG) |
3bcfeaf9 | 31 | if (max_pfn <= max_low_pfn) |
831058de | 32 | return 0; |
3bcfeaf9 | 33 | #endif |
831058de DH |
34 | |
35 | page_pool = mempool_create_page_pool(POOL_SIZE, 0); | |
36 | BUG_ON(!page_pool); | |
f1006257 | 37 | printk("bounce pool size: %d pages\n", POOL_SIZE); |
831058de DH |
38 | |
39 | return 0; | |
40 | } | |
41 | ||
42 | __initcall(init_emergency_pool); | |
f1006257 | 43 | #endif |
831058de | 44 | |
f1006257 | 45 | #ifdef CONFIG_HIGHMEM |
831058de DH |
46 | /* |
47 | * highmem version, map in to vec | |
48 | */ | |
49 | static 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); | |
9b04c5fe | 55 | vto = kmap_atomic(to->bv_page); |
831058de | 56 | memcpy(vto + to->bv_offset, vfrom, to->bv_len); |
9b04c5fe | 57 | kunmap_atomic(vto); |
831058de DH |
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 | */ | |
71 | static 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 | */ | |
80 | int 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 | */ | |
98 | static void copy_to_high_bio_irq(struct bio *to, struct bio *from) | |
99 | { | |
100 | unsigned char *vfrom; | |
7988613b KO |
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 | } | |
831058de | 117 | |
7988613b | 118 | fromvec++; |
831058de DH |
119 | } |
120 | } | |
121 | ||
122 | static 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 | */ | |
d74c6d51 | 134 | bio_for_each_segment_all(bvec, bio, i) { |
831058de DH |
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 | ||
6712ecf8 | 143 | bio_endio(bio_orig, err); |
831058de DH |
144 | bio_put(bio); |
145 | } | |
146 | ||
6712ecf8 | 147 | static void bounce_end_io_write(struct bio *bio, int err) |
831058de | 148 | { |
831058de | 149 | bounce_end_io(bio, page_pool, err); |
831058de DH |
150 | } |
151 | ||
6712ecf8 | 152 | static void bounce_end_io_write_isa(struct bio *bio, int err) |
831058de | 153 | { |
831058de DH |
154 | |
155 | bounce_end_io(bio, isa_page_pool, err); | |
831058de DH |
156 | } |
157 | ||
158 | static 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 | ||
6712ecf8 | 168 | static void bounce_end_io_read(struct bio *bio, int err) |
831058de | 169 | { |
831058de | 170 | __bounce_end_io_read(bio, page_pool, err); |
831058de DH |
171 | } |
172 | ||
6712ecf8 | 173 | static void bounce_end_io_read_isa(struct bio *bio, int err) |
831058de | 174 | { |
831058de | 175 | __bounce_end_io_read(bio, isa_page_pool, err); |
831058de DH |
176 | } |
177 | ||
ffecfd1a DW |
178 | #ifdef CONFIG_NEED_BOUNCE_POOL |
179 | static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio) | |
180 | { | |
ffecfd1a DW |
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 | ||
71368511 | 187 | return test_bit(BIO_SNAP_STABLE, &bio->bi_flags); |
ffecfd1a DW |
188 | } |
189 | #else | |
190 | static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio) | |
191 | { | |
192 | return 0; | |
193 | } | |
194 | #endif /* CONFIG_NEED_BOUNCE_POOL */ | |
195 | ||
165125e1 | 196 | static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, |
ffecfd1a | 197 | mempool_t *pool, int force) |
831058de | 198 | { |
6bc454d1 KO |
199 | struct bio *bio; |
200 | int rw = bio_data_dir(*bio_orig); | |
7988613b KO |
201 | struct bio_vec *to, from; |
202 | struct bvec_iter iter; | |
6bc454d1 | 203 | unsigned i; |
831058de | 204 | |
83b2944f DW |
205 | if (force) |
206 | goto bounce; | |
7988613b KO |
207 | bio_for_each_segment(from, *bio_orig, iter) |
208 | if (page_to_pfn(from.bv_page) > queue_bounce_pfn(q)) | |
6bc454d1 | 209 | goto bounce; |
831058de | 210 | |
6bc454d1 KO |
211 | return; |
212 | bounce: | |
213 | bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set); | |
831058de | 214 | |
cb34e057 | 215 | bio_for_each_segment_all(to, bio, i) { |
6bc454d1 | 216 | struct page *page = to->bv_page; |
f735b5ee | 217 | |
6bc454d1 KO |
218 | if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force) |
219 | continue; | |
831058de | 220 | |
831058de | 221 | inc_zone_page_state(to->bv_page, NR_BOUNCE); |
6bc454d1 | 222 | to->bv_page = mempool_alloc(pool, q->bounce_gfp); |
831058de DH |
223 | |
224 | if (rw == WRITE) { | |
225 | char *vto, *vfrom; | |
226 | ||
6bc454d1 KO |
227 | flush_dcache_page(page); |
228 | ||
831058de | 229 | vto = page_address(to->bv_page) + to->bv_offset; |
6bc454d1 | 230 | vfrom = kmap_atomic(page) + to->bv_offset; |
831058de | 231 | memcpy(vto, vfrom, to->bv_len); |
6bc454d1 | 232 | kunmap_atomic(vfrom); |
831058de DH |
233 | } |
234 | } | |
235 | ||
5f3ea37c | 236 | trace_block_bio_bounce(q, *bio_orig); |
c43a5082 | 237 | |
831058de | 238 | bio->bi_flags |= (1 << BIO_BOUNCED); |
831058de DH |
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 | ||
165125e1 | 254 | void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) |
831058de | 255 | { |
ffecfd1a | 256 | int must_bounce; |
831058de DH |
257 | mempool_t *pool; |
258 | ||
bf2de6f5 JA |
259 | /* |
260 | * Data-less bio, nothing to bounce | |
261 | */ | |
36144077 | 262 | if (!bio_has_data(*bio_orig)) |
bf2de6f5 JA |
263 | return; |
264 | ||
ffecfd1a DW |
265 | must_bounce = must_snapshot_stable_pages(q, *bio_orig); |
266 | ||
831058de DH |
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)) { | |
ffecfd1a | 273 | if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce) |
831058de DH |
274 | return; |
275 | pool = page_pool; | |
276 | } else { | |
277 | BUG_ON(!isa_page_pool); | |
278 | pool = isa_page_pool; | |
279 | } | |
280 | ||
831058de DH |
281 | /* |
282 | * slow path | |
283 | */ | |
ffecfd1a | 284 | __blk_queue_bounce(q, bio_orig, pool, must_bounce); |
831058de DH |
285 | } |
286 | ||
287 | EXPORT_SYMBOL(blk_queue_bounce); |