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David Howells831058d2006-08-29 19:06:00 +01001/* bounce buffer handling for block devices
2 *
3 * - Split from highmem.c
4 */
5
6#include <linux/mm.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -04007#include <linux/export.h>
David Howells831058d2006-08-29 19:06:00 +01008#include <linux/swap.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09009#include <linux/gfp.h>
David Howells831058d2006-08-29 19:06:00 +010010#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>
David Vrabel3bcfeaf2011-10-20 21:24:30 +020017#include <linux/bootmem.h>
David Howells831058d2006-08-29 19:06:00 +010018#include <asm/tlbflush.h>
19
Li Zefan55782132009-06-09 13:43:05 +080020#include <trace/events/block.h>
21
David Howells831058d2006-08-29 19:06:00 +010022#define POOL_SIZE 64
23#define ISA_POOL_SIZE 16
24
25static mempool_t *page_pool, *isa_page_pool;
26
Chris Metcalff1006252012-06-16 16:41:05 -040027#if defined(CONFIG_HIGHMEM) || defined(CONFIG_NEED_BOUNCE_POOL)
David Howells831058d2006-08-29 19:06:00 +010028static __init int init_emergency_pool(void)
29{
Chris Metcalff1006252012-06-16 16:41:05 -040030#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
David Vrabel3bcfeaf2011-10-20 21:24:30 +020031 if (max_pfn <= max_low_pfn)
David Howells831058d2006-08-29 19:06:00 +010032 return 0;
David Vrabel3bcfeaf2011-10-20 21:24:30 +020033#endif
David Howells831058d2006-08-29 19:06:00 +010034
35 page_pool = mempool_create_page_pool(POOL_SIZE, 0);
36 BUG_ON(!page_pool);
Chris Metcalff1006252012-06-16 16:41:05 -040037 printk("bounce pool size: %d pages\n", POOL_SIZE);
David Howells831058d2006-08-29 19:06:00 +010038
39 return 0;
40}
41
42__initcall(init_emergency_pool);
Chris Metcalff1006252012-06-16 16:41:05 -040043#endif
David Howells831058d2006-08-29 19:06:00 +010044
Chris Metcalff1006252012-06-16 16:41:05 -040045#ifdef CONFIG_HIGHMEM
David Howells831058d2006-08-29 19:06:00 +010046/*
47 * highmem version, map in to vec
48 */
49static 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);
Cong Wang9b04c5f2011-11-25 23:14:39 +080055 vto = kmap_atomic(to->bv_page);
David Howells831058d2006-08-29 19:06:00 +010056 memcpy(vto + to->bv_offset, vfrom, to->bv_len);
Cong Wang9b04c5f2011-11-25 23:14:39 +080057 kunmap_atomic(vto);
David Howells831058d2006-08-29 19:06:00 +010058 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 */
71static 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 */
80int 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 */
98static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
99{
100 unsigned char *vfrom;
101 struct bio_vec *tovec, *fromvec;
102 int i;
103
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700104 bio_for_each_segment(tovec, to, i) {
David Howells831058d2006-08-29 19:06:00 +0100105 fromvec = from->bi_io_vec + i;
106
107 /*
108 * not bounced
109 */
110 if (tovec->bv_page == fromvec->bv_page)
111 continue;
112
113 /*
114 * fromvec->bv_offset and fromvec->bv_len might have been
115 * modified by the block layer, so use the original copy,
116 * bounce_copy_vec already uses tovec->bv_len
117 */
118 vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;
119
David Howells831058d2006-08-29 19:06:00 +0100120 bounce_copy_vec(tovec, vfrom);
Gary Kingac8456d2010-09-09 16:38:05 -0700121 flush_dcache_page(tovec->bv_page);
David Howells831058d2006-08-29 19:06:00 +0100122 }
123}
124
125static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
126{
127 struct bio *bio_orig = bio->bi_private;
128 struct bio_vec *bvec, *org_vec;
129 int i;
130
131 if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
132 set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
133
134 /*
135 * free up bounce indirect pages used
136 */
Kent Overstreetd74c6d52013-02-06 12:23:11 -0800137 bio_for_each_segment_all(bvec, bio, i) {
David Howells831058d2006-08-29 19:06:00 +0100138 org_vec = bio_orig->bi_io_vec + i;
139 if (bvec->bv_page == org_vec->bv_page)
140 continue;
141
142 dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
143 mempool_free(bvec->bv_page, pool);
144 }
145
NeilBrown6712ecf2007-09-27 12:47:43 +0200146 bio_endio(bio_orig, err);
David Howells831058d2006-08-29 19:06:00 +0100147 bio_put(bio);
148}
149
NeilBrown6712ecf2007-09-27 12:47:43 +0200150static void bounce_end_io_write(struct bio *bio, int err)
David Howells831058d2006-08-29 19:06:00 +0100151{
David Howells831058d2006-08-29 19:06:00 +0100152 bounce_end_io(bio, page_pool, err);
David Howells831058d2006-08-29 19:06:00 +0100153}
154
NeilBrown6712ecf2007-09-27 12:47:43 +0200155static void bounce_end_io_write_isa(struct bio *bio, int err)
David Howells831058d2006-08-29 19:06:00 +0100156{
David Howells831058d2006-08-29 19:06:00 +0100157
158 bounce_end_io(bio, isa_page_pool, err);
David Howells831058d2006-08-29 19:06:00 +0100159}
160
161static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
162{
163 struct bio *bio_orig = bio->bi_private;
164
165 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
166 copy_to_high_bio_irq(bio_orig, bio);
167
168 bounce_end_io(bio, pool, err);
169}
170
NeilBrown6712ecf2007-09-27 12:47:43 +0200171static void bounce_end_io_read(struct bio *bio, int err)
David Howells831058d2006-08-29 19:06:00 +0100172{
David Howells831058d2006-08-29 19:06:00 +0100173 __bounce_end_io_read(bio, page_pool, err);
David Howells831058d2006-08-29 19:06:00 +0100174}
175
NeilBrown6712ecf2007-09-27 12:47:43 +0200176static void bounce_end_io_read_isa(struct bio *bio, int err)
David Howells831058d2006-08-29 19:06:00 +0100177{
David Howells831058d2006-08-29 19:06:00 +0100178 __bounce_end_io_read(bio, isa_page_pool, err);
David Howells831058d2006-08-29 19:06:00 +0100179}
180
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800181#ifdef CONFIG_NEED_BOUNCE_POOL
182static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
183{
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800184 if (bio_data_dir(bio) != WRITE)
185 return 0;
186
187 if (!bdi_cap_stable_pages_required(&q->backing_dev_info))
188 return 0;
189
Darrick J. Wong7136851112013-04-29 15:07:25 -0700190 return test_bit(BIO_SNAP_STABLE, &bio->bi_flags);
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800191}
192#else
193static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
194{
195 return 0;
196}
197#endif /* CONFIG_NEED_BOUNCE_POOL */
198
Jens Axboe165125e2007-07-24 09:28:11 +0200199static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800200 mempool_t *pool, int force)
David Howells831058d2006-08-29 19:06:00 +0100201{
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700202 struct bio *bio;
203 int rw = bio_data_dir(*bio_orig);
David Howells831058d2006-08-29 19:06:00 +0100204 struct bio_vec *to, *from;
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700205 unsigned i;
David Howells831058d2006-08-29 19:06:00 +0100206
Darrick J. Wong83b29442013-09-30 13:45:09 -0700207 if (force)
208 goto bounce;
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700209 bio_for_each_segment(from, *bio_orig, i)
210 if (page_to_pfn(from->bv_page) > queue_bounce_pfn(q))
211 goto bounce;
David Howells831058d2006-08-29 19:06:00 +0100212
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700213 return;
214bounce:
215 bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);
216
Kent Overstreetcb34e052012-09-05 15:22:02 -0700217 bio_for_each_segment_all(to, bio, i) {
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700218 struct page *page = to->bv_page;
219
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800220 if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force)
David Howells831058d2006-08-29 19:06:00 +0100221 continue;
222
David Howells831058d2006-08-29 19:06:00 +0100223 inc_zone_page_state(to->bv_page, NR_BOUNCE);
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700224 to->bv_page = mempool_alloc(pool, q->bounce_gfp);
David Howells831058d2006-08-29 19:06:00 +0100225
226 if (rw == WRITE) {
227 char *vto, *vfrom;
228
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700229 flush_dcache_page(page);
230
David Howells831058d2006-08-29 19:06:00 +0100231 vto = page_address(to->bv_page) + to->bv_offset;
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700232 vfrom = kmap_atomic(page) + to->bv_offset;
David Howells831058d2006-08-29 19:06:00 +0100233 memcpy(vto, vfrom, to->bv_len);
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700234 kunmap_atomic(vfrom);
David Howells831058d2006-08-29 19:06:00 +0100235 }
236 }
237
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +0100238 trace_block_bio_bounce(q, *bio_orig);
Jens Axboec43a5082007-01-12 12:20:26 +0100239
David Howells831058d2006-08-29 19:06:00 +0100240 bio->bi_flags |= (1 << BIO_BOUNCED);
David Howells831058d2006-08-29 19:06:00 +0100241
242 if (pool == page_pool) {
243 bio->bi_end_io = bounce_end_io_write;
244 if (rw == READ)
245 bio->bi_end_io = bounce_end_io_read;
246 } else {
247 bio->bi_end_io = bounce_end_io_write_isa;
248 if (rw == READ)
249 bio->bi_end_io = bounce_end_io_read_isa;
250 }
251
252 bio->bi_private = *bio_orig;
253 *bio_orig = bio;
254}
255
Jens Axboe165125e2007-07-24 09:28:11 +0200256void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
David Howells831058d2006-08-29 19:06:00 +0100257{
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800258 int must_bounce;
David Howells831058d2006-08-29 19:06:00 +0100259 mempool_t *pool;
260
261 /*
Jens Axboebf2de6f2007-09-27 13:01:25 +0200262 * Data-less bio, nothing to bounce
263 */
Jens Axboe36144072008-08-14 13:12:15 +0200264 if (!bio_has_data(*bio_orig))
Jens Axboebf2de6f2007-09-27 13:01:25 +0200265 return;
266
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800267 must_bounce = must_snapshot_stable_pages(q, *bio_orig);
268
Jens Axboebf2de6f2007-09-27 13:01:25 +0200269 /*
David Howells831058d2006-08-29 19:06:00 +0100270 * for non-isa bounce case, just check if the bounce pfn is equal
271 * to or bigger than the highest pfn in the system -- in that case,
272 * don't waste time iterating over bio segments
273 */
274 if (!(q->bounce_gfp & GFP_DMA)) {
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800275 if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce)
David Howells831058d2006-08-29 19:06:00 +0100276 return;
277 pool = page_pool;
278 } else {
279 BUG_ON(!isa_page_pool);
280 pool = isa_page_pool;
281 }
282
David Howells831058d2006-08-29 19:06:00 +0100283 /*
284 * slow path
285 */
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800286 __blk_queue_bounce(q, bio_orig, pool, must_bounce);
David Howells831058d2006-08-29 19:06:00 +0100287}
288
289EXPORT_SYMBOL(blk_queue_bounce);