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