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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
831058de DH |
2 | /* bounce buffer handling for block devices |
3 | * | |
4 | * - Split from highmem.c | |
5 | */ | |
6 | ||
b1de0d13 MH |
7 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
8 | ||
831058de | 9 | #include <linux/mm.h> |
b95f1b31 | 10 | #include <linux/export.h> |
831058de | 11 | #include <linux/swap.h> |
5a0e3ad6 | 12 | #include <linux/gfp.h> |
831058de DH |
13 | #include <linux/bio.h> |
14 | #include <linux/pagemap.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/blkdev.h> | |
66114cad | 17 | #include <linux/backing-dev.h> |
831058de DH |
18 | #include <linux/init.h> |
19 | #include <linux/hash.h> | |
20 | #include <linux/highmem.h> | |
3bcfeaf9 | 21 | #include <linux/bootmem.h> |
b1de0d13 | 22 | #include <linux/printk.h> |
831058de DH |
23 | #include <asm/tlbflush.h> |
24 | ||
55782138 | 25 | #include <trace/events/block.h> |
3bce016a | 26 | #include "blk.h" |
55782138 | 27 | |
831058de DH |
28 | #define POOL_SIZE 64 |
29 | #define ISA_POOL_SIZE 16 | |
30 | ||
e0fc443a | 31 | static struct bio_set *bounce_bio_set, *bounce_bio_split; |
831058de DH |
32 | static mempool_t *page_pool, *isa_page_pool; |
33 | ||
a687a533 | 34 | #if defined(CONFIG_HIGHMEM) |
831058de DH |
35 | static __init int init_emergency_pool(void) |
36 | { | |
f1006257 | 37 | #if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG) |
3bcfeaf9 | 38 | if (max_pfn <= max_low_pfn) |
831058de | 39 | return 0; |
3bcfeaf9 | 40 | #endif |
831058de DH |
41 | |
42 | page_pool = mempool_create_page_pool(POOL_SIZE, 0); | |
43 | BUG_ON(!page_pool); | |
b1de0d13 | 44 | pr_info("pool size: %d pages\n", POOL_SIZE); |
831058de | 45 | |
a8821f3f N |
46 | bounce_bio_set = bioset_create(BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS); |
47 | BUG_ON(!bounce_bio_set); | |
48 | if (bioset_integrity_create(bounce_bio_set, BIO_POOL_SIZE)) | |
49 | BUG_ON(1); | |
50 | ||
51 | bounce_bio_split = bioset_create(BIO_POOL_SIZE, 0, 0); | |
52 | BUG_ON(!bounce_bio_split); | |
53 | ||
831058de DH |
54 | return 0; |
55 | } | |
56 | ||
57 | __initcall(init_emergency_pool); | |
f1006257 | 58 | #endif |
831058de | 59 | |
f1006257 | 60 | #ifdef CONFIG_HIGHMEM |
831058de DH |
61 | /* |
62 | * highmem version, map in to vec | |
63 | */ | |
64 | static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom) | |
65 | { | |
831058de DH |
66 | unsigned char *vto; |
67 | ||
9b04c5fe | 68 | vto = kmap_atomic(to->bv_page); |
831058de | 69 | memcpy(vto + to->bv_offset, vfrom, to->bv_len); |
9b04c5fe | 70 | kunmap_atomic(vto); |
831058de DH |
71 | } |
72 | ||
73 | #else /* CONFIG_HIGHMEM */ | |
74 | ||
75 | #define bounce_copy_vec(to, vfrom) \ | |
76 | memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len) | |
77 | ||
78 | #endif /* CONFIG_HIGHMEM */ | |
79 | ||
80 | /* | |
81 | * allocate pages in the DMA region for the ISA pool | |
82 | */ | |
83 | static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data) | |
84 | { | |
85 | return mempool_alloc_pages(gfp_mask | GFP_DMA, data); | |
86 | } | |
87 | ||
88 | /* | |
89 | * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA | |
90 | * as the max address, so check if the pool has already been created. | |
91 | */ | |
92 | int init_emergency_isa_pool(void) | |
93 | { | |
94 | if (isa_page_pool) | |
95 | return 0; | |
96 | ||
97 | isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa, | |
98 | mempool_free_pages, (void *) 0); | |
99 | BUG_ON(!isa_page_pool); | |
100 | ||
b1de0d13 | 101 | pr_info("isa pool size: %d pages\n", ISA_POOL_SIZE); |
831058de DH |
102 | return 0; |
103 | } | |
104 | ||
105 | /* | |
106 | * Simple bounce buffer support for highmem pages. Depending on the | |
107 | * queue gfp mask set, *to may or may not be a highmem page. kmap it | |
108 | * always, it will do the Right Thing | |
109 | */ | |
110 | static void copy_to_high_bio_irq(struct bio *to, struct bio *from) | |
111 | { | |
112 | unsigned char *vfrom; | |
3c892a09 | 113 | struct bio_vec tovec, fromvec; |
7988613b | 114 | struct bvec_iter iter; |
3c892a09 ML |
115 | /* |
116 | * The bio of @from is created by bounce, so we can iterate | |
117 | * its bvec from start to end, but the @from->bi_iter can't be | |
118 | * trusted because it might be changed by splitting. | |
119 | */ | |
120 | struct bvec_iter from_iter = BVEC_ITER_ALL_INIT; | |
7988613b KO |
121 | |
122 | bio_for_each_segment(tovec, to, iter) { | |
3c892a09 ML |
123 | fromvec = bio_iter_iovec(from, from_iter); |
124 | if (tovec.bv_page != fromvec.bv_page) { | |
7988613b KO |
125 | /* |
126 | * fromvec->bv_offset and fromvec->bv_len might have | |
127 | * been modified by the block layer, so use the original | |
128 | * copy, bounce_copy_vec already uses tovec->bv_len | |
129 | */ | |
3c892a09 | 130 | vfrom = page_address(fromvec.bv_page) + |
7988613b KO |
131 | tovec.bv_offset; |
132 | ||
133 | bounce_copy_vec(&tovec, vfrom); | |
134 | flush_dcache_page(tovec.bv_page); | |
135 | } | |
3c892a09 | 136 | bio_advance_iter(from, &from_iter, tovec.bv_len); |
831058de DH |
137 | } |
138 | } | |
139 | ||
4246a0b6 | 140 | static void bounce_end_io(struct bio *bio, mempool_t *pool) |
831058de DH |
141 | { |
142 | struct bio *bio_orig = bio->bi_private; | |
7891f05c | 143 | struct bio_vec *bvec, orig_vec; |
831058de | 144 | int i; |
7891f05c | 145 | struct bvec_iter orig_iter = bio_orig->bi_iter; |
831058de | 146 | |
831058de DH |
147 | /* |
148 | * free up bounce indirect pages used | |
149 | */ | |
d74c6d51 | 150 | bio_for_each_segment_all(bvec, bio, i) { |
7891f05c ML |
151 | orig_vec = bio_iter_iovec(bio_orig, orig_iter); |
152 | if (bvec->bv_page != orig_vec.bv_page) { | |
153 | dec_zone_page_state(bvec->bv_page, NR_BOUNCE); | |
154 | mempool_free(bvec->bv_page, pool); | |
155 | } | |
156 | bio_advance_iter(bio_orig, &orig_iter, orig_vec.bv_len); | |
831058de DH |
157 | } |
158 | ||
4e4cbee9 | 159 | bio_orig->bi_status = bio->bi_status; |
4246a0b6 | 160 | bio_endio(bio_orig); |
831058de DH |
161 | bio_put(bio); |
162 | } | |
163 | ||
4246a0b6 | 164 | static void bounce_end_io_write(struct bio *bio) |
831058de | 165 | { |
4246a0b6 | 166 | bounce_end_io(bio, page_pool); |
831058de DH |
167 | } |
168 | ||
4246a0b6 | 169 | static void bounce_end_io_write_isa(struct bio *bio) |
831058de | 170 | { |
831058de | 171 | |
4246a0b6 | 172 | bounce_end_io(bio, isa_page_pool); |
831058de DH |
173 | } |
174 | ||
4246a0b6 | 175 | static void __bounce_end_io_read(struct bio *bio, mempool_t *pool) |
831058de DH |
176 | { |
177 | struct bio *bio_orig = bio->bi_private; | |
178 | ||
4e4cbee9 | 179 | if (!bio->bi_status) |
831058de DH |
180 | copy_to_high_bio_irq(bio_orig, bio); |
181 | ||
4246a0b6 | 182 | bounce_end_io(bio, pool); |
831058de DH |
183 | } |
184 | ||
4246a0b6 | 185 | static void bounce_end_io_read(struct bio *bio) |
831058de | 186 | { |
4246a0b6 | 187 | __bounce_end_io_read(bio, page_pool); |
831058de DH |
188 | } |
189 | ||
4246a0b6 | 190 | static void bounce_end_io_read_isa(struct bio *bio) |
831058de | 191 | { |
4246a0b6 | 192 | __bounce_end_io_read(bio, isa_page_pool); |
831058de DH |
193 | } |
194 | ||
165125e1 | 195 | static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, |
a3ad0a9d | 196 | mempool_t *pool) |
831058de | 197 | { |
6bc454d1 KO |
198 | struct bio *bio; |
199 | int rw = bio_data_dir(*bio_orig); | |
7988613b KO |
200 | struct bio_vec *to, from; |
201 | struct bvec_iter iter; | |
a8821f3f N |
202 | unsigned i = 0; |
203 | bool bounce = false; | |
204 | int sectors = 0; | |
14cb0dc6 | 205 | bool passthrough = bio_is_passthrough(*bio_orig); |
831058de | 206 | |
a8821f3f N |
207 | bio_for_each_segment(from, *bio_orig, iter) { |
208 | if (i++ < BIO_MAX_PAGES) | |
209 | sectors += from.bv_len >> 9; | |
1c4bc3ab | 210 | if (page_to_pfn(from.bv_page) > q->limits.bounce_pfn) |
a8821f3f N |
211 | bounce = true; |
212 | } | |
213 | if (!bounce) | |
214 | return; | |
215 | ||
14cb0dc6 | 216 | if (!passthrough && sectors < bio_sectors(*bio_orig)) { |
a8821f3f N |
217 | bio = bio_split(*bio_orig, sectors, GFP_NOIO, bounce_bio_split); |
218 | bio_chain(bio, *bio_orig); | |
219 | generic_make_request(*bio_orig); | |
220 | *bio_orig = bio; | |
221 | } | |
14cb0dc6 ML |
222 | bio = bio_clone_bioset(*bio_orig, GFP_NOIO, passthrough ? NULL : |
223 | bounce_bio_set); | |
831058de | 224 | |
cb34e057 | 225 | bio_for_each_segment_all(to, bio, i) { |
6bc454d1 | 226 | struct page *page = to->bv_page; |
f735b5ee | 227 | |
1c4bc3ab | 228 | if (page_to_pfn(page) <= q->limits.bounce_pfn) |
6bc454d1 | 229 | continue; |
831058de | 230 | |
6bc454d1 | 231 | to->bv_page = mempool_alloc(pool, q->bounce_gfp); |
393a3397 | 232 | inc_zone_page_state(to->bv_page, NR_BOUNCE); |
831058de DH |
233 | |
234 | if (rw == WRITE) { | |
235 | char *vto, *vfrom; | |
236 | ||
6bc454d1 KO |
237 | flush_dcache_page(page); |
238 | ||
831058de | 239 | vto = page_address(to->bv_page) + to->bv_offset; |
6bc454d1 | 240 | vfrom = kmap_atomic(page) + to->bv_offset; |
831058de | 241 | memcpy(vto, vfrom, to->bv_len); |
6bc454d1 | 242 | kunmap_atomic(vfrom); |
831058de DH |
243 | } |
244 | } | |
245 | ||
5f3ea37c | 246 | trace_block_bio_bounce(q, *bio_orig); |
c43a5082 | 247 | |
831058de | 248 | bio->bi_flags |= (1 << BIO_BOUNCED); |
831058de DH |
249 | |
250 | if (pool == page_pool) { | |
251 | bio->bi_end_io = bounce_end_io_write; | |
252 | if (rw == READ) | |
253 | bio->bi_end_io = bounce_end_io_read; | |
254 | } else { | |
255 | bio->bi_end_io = bounce_end_io_write_isa; | |
256 | if (rw == READ) | |
257 | bio->bi_end_io = bounce_end_io_read_isa; | |
258 | } | |
259 | ||
260 | bio->bi_private = *bio_orig; | |
261 | *bio_orig = bio; | |
262 | } | |
263 | ||
165125e1 | 264 | void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) |
831058de DH |
265 | { |
266 | mempool_t *pool; | |
267 | ||
bf2de6f5 JA |
268 | /* |
269 | * Data-less bio, nothing to bounce | |
270 | */ | |
36144077 | 271 | if (!bio_has_data(*bio_orig)) |
bf2de6f5 JA |
272 | return; |
273 | ||
831058de DH |
274 | /* |
275 | * for non-isa bounce case, just check if the bounce pfn is equal | |
276 | * to or bigger than the highest pfn in the system -- in that case, | |
277 | * don't waste time iterating over bio segments | |
278 | */ | |
279 | if (!(q->bounce_gfp & GFP_DMA)) { | |
1c4bc3ab | 280 | if (q->limits.bounce_pfn >= blk_max_pfn) |
831058de DH |
281 | return; |
282 | pool = page_pool; | |
283 | } else { | |
284 | BUG_ON(!isa_page_pool); | |
285 | pool = isa_page_pool; | |
286 | } | |
287 | ||
831058de DH |
288 | /* |
289 | * slow path | |
290 | */ | |
a3ad0a9d | 291 | __blk_queue_bounce(q, bio_orig, pool); |
831058de | 292 | } |