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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - block/bounce.c
1 // SPDX-License-Identifier: GPL-2.0
2 /* bounce buffer handling for block devices
4 * - Split from highmem.c
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
25 #include <trace/events/block.h>
29 #define ISA_POOL_SIZE 16
31 static struct bio_set
*bounce_bio_set
, *bounce_bio_split
;
32 static mempool_t
*page_pool
, *isa_page_pool
;
34 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_NEED_BOUNCE_POOL)
35 static __init
int init_emergency_pool(void)
37 #if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
38 if (max_pfn
<= max_low_pfn
)
42 page_pool
= mempool_create_page_pool(POOL_SIZE
, 0);
44 pr_info("pool size: %d pages\n", POOL_SIZE
);
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
))
51 bounce_bio_split
= bioset_create(BIO_POOL_SIZE
, 0, 0);
52 BUG_ON(!bounce_bio_split
);
57 __initcall(init_emergency_pool
);
62 * highmem version, map in to vec
64 static void bounce_copy_vec(struct bio_vec
*to
, unsigned char *vfrom
)
69 local_irq_save(flags
);
70 vto
= kmap_atomic(to
->bv_page
);
71 memcpy(vto
+ to
->bv_offset
, vfrom
, to
->bv_len
);
73 local_irq_restore(flags
);
76 #else /* CONFIG_HIGHMEM */
78 #define bounce_copy_vec(to, vfrom) \
79 memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
81 #endif /* CONFIG_HIGHMEM */
84 * allocate pages in the DMA region for the ISA pool
86 static void *mempool_alloc_pages_isa(gfp_t gfp_mask
, void *data
)
88 return mempool_alloc_pages(gfp_mask
| GFP_DMA
, data
);
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.
95 int init_emergency_isa_pool(void)
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
);
104 pr_info("isa pool size: %d pages\n", ISA_POOL_SIZE
);
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
113 static void copy_to_high_bio_irq(struct bio
*to
, struct bio
*from
)
115 unsigned char *vfrom
;
116 struct bio_vec tovec
, *fromvec
= from
->bi_io_vec
;
117 struct bvec_iter iter
;
119 bio_for_each_segment(tovec
, to
, iter
) {
120 if (tovec
.bv_page
!= fromvec
->bv_page
) {
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
126 vfrom
= page_address(fromvec
->bv_page
) +
129 bounce_copy_vec(&tovec
, vfrom
);
130 flush_dcache_page(tovec
.bv_page
);
137 static void bounce_end_io(struct bio
*bio
, mempool_t
*pool
)
139 struct bio
*bio_orig
= bio
->bi_private
;
140 struct bio_vec
*bvec
, *org_vec
;
142 int start
= bio_orig
->bi_iter
.bi_idx
;
145 * free up bounce indirect pages used
147 bio_for_each_segment_all(bvec
, bio
, i
) {
148 org_vec
= bio_orig
->bi_io_vec
+ i
+ start
;
150 if (bvec
->bv_page
== org_vec
->bv_page
)
153 dec_zone_page_state(bvec
->bv_page
, NR_BOUNCE
);
154 mempool_free(bvec
->bv_page
, pool
);
157 bio_orig
->bi_status
= bio
->bi_status
;
162 static void bounce_end_io_write(struct bio
*bio
)
164 bounce_end_io(bio
, page_pool
);
167 static void bounce_end_io_write_isa(struct bio
*bio
)
170 bounce_end_io(bio
, isa_page_pool
);
173 static void __bounce_end_io_read(struct bio
*bio
, mempool_t
*pool
)
175 struct bio
*bio_orig
= bio
->bi_private
;
178 copy_to_high_bio_irq(bio_orig
, bio
);
180 bounce_end_io(bio
, pool
);
183 static void bounce_end_io_read(struct bio
*bio
)
185 __bounce_end_io_read(bio
, page_pool
);
188 static void bounce_end_io_read_isa(struct bio
*bio
)
190 __bounce_end_io_read(bio
, isa_page_pool
);
193 static void __blk_queue_bounce(struct request_queue
*q
, struct bio
**bio_orig
,
197 int rw
= bio_data_dir(*bio_orig
);
198 struct bio_vec
*to
, from
;
199 struct bvec_iter iter
;
203 bool passthrough
= bio_is_passthrough(*bio_orig
);
205 bio_for_each_segment(from
, *bio_orig
, iter
) {
206 if (i
++ < BIO_MAX_PAGES
)
207 sectors
+= from
.bv_len
>> 9;
208 if (page_to_pfn(from
.bv_page
) > q
->limits
.bounce_pfn
)
214 if (!passthrough
&& sectors
< bio_sectors(*bio_orig
)) {
215 bio
= bio_split(*bio_orig
, sectors
, GFP_NOIO
, bounce_bio_split
);
216 bio_chain(bio
, *bio_orig
);
217 generic_make_request(*bio_orig
);
220 bio
= bio_clone_bioset(*bio_orig
, GFP_NOIO
, passthrough
? NULL
:
223 bio_for_each_segment_all(to
, bio
, i
) {
224 struct page
*page
= to
->bv_page
;
226 if (page_to_pfn(page
) <= q
->limits
.bounce_pfn
)
229 to
->bv_page
= mempool_alloc(pool
, q
->bounce_gfp
);
230 inc_zone_page_state(to
->bv_page
, NR_BOUNCE
);
235 flush_dcache_page(page
);
237 vto
= page_address(to
->bv_page
) + to
->bv_offset
;
238 vfrom
= kmap_atomic(page
) + to
->bv_offset
;
239 memcpy(vto
, vfrom
, to
->bv_len
);
240 kunmap_atomic(vfrom
);
244 trace_block_bio_bounce(q
, *bio_orig
);
246 bio
->bi_flags
|= (1 << BIO_BOUNCED
);
248 if (pool
== page_pool
) {
249 bio
->bi_end_io
= bounce_end_io_write
;
251 bio
->bi_end_io
= bounce_end_io_read
;
253 bio
->bi_end_io
= bounce_end_io_write_isa
;
255 bio
->bi_end_io
= bounce_end_io_read_isa
;
258 bio
->bi_private
= *bio_orig
;
262 void blk_queue_bounce(struct request_queue
*q
, struct bio
**bio_orig
)
267 * Data-less bio, nothing to bounce
269 if (!bio_has_data(*bio_orig
))
273 * for non-isa bounce case, just check if the bounce pfn is equal
274 * to or bigger than the highest pfn in the system -- in that case,
275 * don't waste time iterating over bio segments
277 if (!(q
->bounce_gfp
& GFP_DMA
)) {
278 if (q
->limits
.bounce_pfn
>= blk_max_pfn
)
282 BUG_ON(!isa_page_pool
);
283 pool
= isa_page_pool
;
289 __blk_queue_bounce(q
, bio_orig
, pool
);