blob: 072280b3dd138e7cecf555c914fbb99c0589d618 [file] [log] [blame]
David Howells831058d2006-08-29 19:06:00 +01001/* bounce buffer handling for block devices
2 *
3 * - Split from highmem.c
4 */
5
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -07006#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
David Howells831058d2006-08-29 19:06:00 +01008#include <linux/mm.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -04009#include <linux/export.h>
David Howells831058d2006-08-29 19:06:00 +010010#include <linux/swap.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090011#include <linux/gfp.h>
David Howells831058d2006-08-29 19:06:00 +010012#include <linux/bio.h>
13#include <linux/pagemap.h>
14#include <linux/mempool.h>
15#include <linux/blkdev.h>
Tejun Heo66114ca2015-05-22 17:13:32 -040016#include <linux/backing-dev.h>
David Howells831058d2006-08-29 19:06:00 +010017#include <linux/init.h>
18#include <linux/hash.h>
19#include <linux/highmem.h>
David Vrabel3bcfeaf2011-10-20 21:24:30 +020020#include <linux/bootmem.h>
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -070021#include <linux/printk.h>
David Howells831058d2006-08-29 19:06:00 +010022#include <asm/tlbflush.h>
23
Li Zefan55782132009-06-09 13:43:05 +080024#include <trace/events/block.h>
25
David Howells831058d2006-08-29 19:06:00 +010026#define POOL_SIZE 64
27#define ISA_POOL_SIZE 16
28
29static mempool_t *page_pool, *isa_page_pool;
30
Chris Metcalff1006252012-06-16 16:41:05 -040031#if defined(CONFIG_HIGHMEM) || defined(CONFIG_NEED_BOUNCE_POOL)
David Howells831058d2006-08-29 19:06:00 +010032static __init int init_emergency_pool(void)
33{
Chris Metcalff1006252012-06-16 16:41:05 -040034#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
David Vrabel3bcfeaf2011-10-20 21:24:30 +020035 if (max_pfn <= max_low_pfn)
David Howells831058d2006-08-29 19:06:00 +010036 return 0;
David Vrabel3bcfeaf2011-10-20 21:24:30 +020037#endif
David Howells831058d2006-08-29 19:06:00 +010038
39 page_pool = mempool_create_page_pool(POOL_SIZE, 0);
40 BUG_ON(!page_pool);
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -070041 pr_info("pool size: %d pages\n", POOL_SIZE);
David Howells831058d2006-08-29 19:06:00 +010042
43 return 0;
44}
45
46__initcall(init_emergency_pool);
Chris Metcalff1006252012-06-16 16:41:05 -040047#endif
David Howells831058d2006-08-29 19:06:00 +010048
Chris Metcalff1006252012-06-16 16:41:05 -040049#ifdef CONFIG_HIGHMEM
David Howells831058d2006-08-29 19:06:00 +010050/*
51 * highmem version, map in to vec
52 */
53static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
54{
55 unsigned long flags;
56 unsigned char *vto;
57
58 local_irq_save(flags);
Cong Wang9b04c5f2011-11-25 23:14:39 +080059 vto = kmap_atomic(to->bv_page);
David Howells831058d2006-08-29 19:06:00 +010060 memcpy(vto + to->bv_offset, vfrom, to->bv_len);
Cong Wang9b04c5f2011-11-25 23:14:39 +080061 kunmap_atomic(vto);
David Howells831058d2006-08-29 19:06:00 +010062 local_irq_restore(flags);
63}
64
65#else /* CONFIG_HIGHMEM */
66
67#define bounce_copy_vec(to, vfrom) \
68 memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
69
70#endif /* CONFIG_HIGHMEM */
71
72/*
73 * allocate pages in the DMA region for the ISA pool
74 */
75static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
76{
77 return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
78}
79
80/*
81 * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
82 * as the max address, so check if the pool has already been created.
83 */
84int init_emergency_isa_pool(void)
85{
86 if (isa_page_pool)
87 return 0;
88
89 isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
90 mempool_free_pages, (void *) 0);
91 BUG_ON(!isa_page_pool);
92
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -070093 pr_info("isa pool size: %d pages\n", ISA_POOL_SIZE);
David Howells831058d2006-08-29 19:06:00 +010094 return 0;
95}
96
97/*
98 * Simple bounce buffer support for highmem pages. Depending on the
99 * queue gfp mask set, *to may or may not be a highmem page. kmap it
100 * always, it will do the Right Thing
101 */
102static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
103{
104 unsigned char *vfrom;
Kent Overstreet79886132013-11-23 17:19:00 -0800105 struct bio_vec tovec, *fromvec = from->bi_io_vec;
106 struct bvec_iter iter;
David Howells831058d2006-08-29 19:06:00 +0100107
Kent Overstreet79886132013-11-23 17:19:00 -0800108 bio_for_each_segment(tovec, to, iter) {
109 if (tovec.bv_page != fromvec->bv_page) {
110 /*
111 * fromvec->bv_offset and fromvec->bv_len might have
112 * been modified by the block layer, so use the original
113 * copy, bounce_copy_vec already uses tovec->bv_len
114 */
115 vfrom = page_address(fromvec->bv_page) +
116 tovec.bv_offset;
David Howells831058d2006-08-29 19:06:00 +0100117
Kent Overstreet79886132013-11-23 17:19:00 -0800118 bounce_copy_vec(&tovec, vfrom);
119 flush_dcache_page(tovec.bv_page);
120 }
David Howells831058d2006-08-29 19:06:00 +0100121
Kent Overstreet79886132013-11-23 17:19:00 -0800122 fromvec++;
David Howells831058d2006-08-29 19:06:00 +0100123 }
124}
125
126static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
127{
128 struct bio *bio_orig = bio->bi_private;
129 struct bio_vec *bvec, *org_vec;
130 int i;
131
David Howells831058d2006-08-29 19:06:00 +0100132 /*
133 * free up bounce indirect pages used
134 */
Kent Overstreetd74c6d52013-02-06 12:23:11 -0800135 bio_for_each_segment_all(bvec, bio, i) {
David Howells831058d2006-08-29 19:06:00 +0100136 org_vec = bio_orig->bi_io_vec + i;
137 if (bvec->bv_page == org_vec->bv_page)
138 continue;
139
140 dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
141 mempool_free(bvec->bv_page, pool);
142 }
143
NeilBrown6712ecf2007-09-27 12:47:43 +0200144 bio_endio(bio_orig, err);
David Howells831058d2006-08-29 19:06:00 +0100145 bio_put(bio);
146}
147
NeilBrown6712ecf2007-09-27 12:47:43 +0200148static void bounce_end_io_write(struct bio *bio, int err)
David Howells831058d2006-08-29 19:06:00 +0100149{
David Howells831058d2006-08-29 19:06:00 +0100150 bounce_end_io(bio, page_pool, err);
David Howells831058d2006-08-29 19:06:00 +0100151}
152
NeilBrown6712ecf2007-09-27 12:47:43 +0200153static void bounce_end_io_write_isa(struct bio *bio, int err)
David Howells831058d2006-08-29 19:06:00 +0100154{
David Howells831058d2006-08-29 19:06:00 +0100155
156 bounce_end_io(bio, isa_page_pool, err);
David Howells831058d2006-08-29 19:06:00 +0100157}
158
159static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
160{
161 struct bio *bio_orig = bio->bi_private;
162
163 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
164 copy_to_high_bio_irq(bio_orig, bio);
165
166 bounce_end_io(bio, pool, err);
167}
168
NeilBrown6712ecf2007-09-27 12:47:43 +0200169static void bounce_end_io_read(struct bio *bio, int err)
David Howells831058d2006-08-29 19:06:00 +0100170{
David Howells831058d2006-08-29 19:06:00 +0100171 __bounce_end_io_read(bio, page_pool, err);
David Howells831058d2006-08-29 19:06:00 +0100172}
173
NeilBrown6712ecf2007-09-27 12:47:43 +0200174static void bounce_end_io_read_isa(struct bio *bio, int err)
David Howells831058d2006-08-29 19:06:00 +0100175{
David Howells831058d2006-08-29 19:06:00 +0100176 __bounce_end_io_read(bio, isa_page_pool, err);
David Howells831058d2006-08-29 19:06:00 +0100177}
178
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800179#ifdef CONFIG_NEED_BOUNCE_POOL
180static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
181{
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800182 if (bio_data_dir(bio) != WRITE)
183 return 0;
184
185 if (!bdi_cap_stable_pages_required(&q->backing_dev_info))
186 return 0;
187
Darrick J. Wong7136851112013-04-29 15:07:25 -0700188 return test_bit(BIO_SNAP_STABLE, &bio->bi_flags);
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800189}
190#else
191static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
192{
193 return 0;
194}
195#endif /* CONFIG_NEED_BOUNCE_POOL */
196
Jens Axboe165125e2007-07-24 09:28:11 +0200197static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800198 mempool_t *pool, int force)
David Howells831058d2006-08-29 19:06:00 +0100199{
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700200 struct bio *bio;
201 int rw = bio_data_dir(*bio_orig);
Kent Overstreet79886132013-11-23 17:19:00 -0800202 struct bio_vec *to, from;
203 struct bvec_iter iter;
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700204 unsigned i;
David Howells831058d2006-08-29 19:06:00 +0100205
Darrick J. Wong83b29442013-09-30 13:45:09 -0700206 if (force)
207 goto bounce;
Kent Overstreet79886132013-11-23 17:19:00 -0800208 bio_for_each_segment(from, *bio_orig, iter)
209 if (page_to_pfn(from.bv_page) > queue_bounce_pfn(q))
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700210 goto bounce;
David Howells831058d2006-08-29 19:06:00 +0100211
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700212 return;
213bounce:
214 bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);
215
Kent Overstreetcb34e052012-09-05 15:22:02 -0700216 bio_for_each_segment_all(to, bio, i) {
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700217 struct page *page = to->bv_page;
218
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800219 if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force)
David Howells831058d2006-08-29 19:06:00 +0100220 continue;
221
David Howells831058d2006-08-29 19:06:00 +0100222 inc_zone_page_state(to->bv_page, NR_BOUNCE);
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700223 to->bv_page = mempool_alloc(pool, q->bounce_gfp);
David Howells831058d2006-08-29 19:06:00 +0100224
225 if (rw == WRITE) {
226 char *vto, *vfrom;
227
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700228 flush_dcache_page(page);
229
David Howells831058d2006-08-29 19:06:00 +0100230 vto = page_address(to->bv_page) + to->bv_offset;
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700231 vfrom = kmap_atomic(page) + to->bv_offset;
David Howells831058d2006-08-29 19:06:00 +0100232 memcpy(vto, vfrom, to->bv_len);
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700233 kunmap_atomic(vfrom);
David Howells831058d2006-08-29 19:06:00 +0100234 }
235 }
236
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +0100237 trace_block_bio_bounce(q, *bio_orig);
Jens Axboec43a5082007-01-12 12:20:26 +0100238
David Howells831058d2006-08-29 19:06:00 +0100239 bio->bi_flags |= (1 << BIO_BOUNCED);
David Howells831058d2006-08-29 19:06:00 +0100240
241 if (pool == page_pool) {
242 bio->bi_end_io = bounce_end_io_write;
243 if (rw == READ)
244 bio->bi_end_io = bounce_end_io_read;
245 } else {
246 bio->bi_end_io = bounce_end_io_write_isa;
247 if (rw == READ)
248 bio->bi_end_io = bounce_end_io_read_isa;
249 }
250
251 bio->bi_private = *bio_orig;
252 *bio_orig = bio;
253}
254
Jens Axboe165125e2007-07-24 09:28:11 +0200255void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
David Howells831058d2006-08-29 19:06:00 +0100256{
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800257 int must_bounce;
David Howells831058d2006-08-29 19:06:00 +0100258 mempool_t *pool;
259
260 /*
Jens Axboebf2de6f2007-09-27 13:01:25 +0200261 * Data-less bio, nothing to bounce
262 */
Jens Axboe36144072008-08-14 13:12:15 +0200263 if (!bio_has_data(*bio_orig))
Jens Axboebf2de6f2007-09-27 13:01:25 +0200264 return;
265
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800266 must_bounce = must_snapshot_stable_pages(q, *bio_orig);
267
Jens Axboebf2de6f2007-09-27 13:01:25 +0200268 /*
David Howells831058d2006-08-29 19:06:00 +0100269 * for non-isa bounce case, just check if the bounce pfn is equal
270 * to or bigger than the highest pfn in the system -- in that case,
271 * don't waste time iterating over bio segments
272 */
273 if (!(q->bounce_gfp & GFP_DMA)) {
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800274 if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce)
David Howells831058d2006-08-29 19:06:00 +0100275 return;
276 pool = page_pool;
277 } else {
278 BUG_ON(!isa_page_pool);
279 pool = isa_page_pool;
280 }
281
David Howells831058d2006-08-29 19:06:00 +0100282 /*
283 * slow path
284 */
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800285 __blk_queue_bounce(q, bio_orig, pool, must_bounce);
David Howells831058d2006-08-29 19:06:00 +0100286}
287
288EXPORT_SYMBOL(blk_queue_bounce);