blob: ed9dd80671204bdebc4005544097fb05b6c90c62 [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>
16#include <linux/init.h>
17#include <linux/hash.h>
18#include <linux/highmem.h>
David Vrabel3bcfeaf2011-10-20 21:24:30 +020019#include <linux/bootmem.h>
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -070020#include <linux/printk.h>
David Howells831058d2006-08-29 19:06:00 +010021#include <asm/tlbflush.h>
22
Li Zefan55782132009-06-09 13:43:05 +080023#include <trace/events/block.h>
24
David Howells831058d2006-08-29 19:06:00 +010025#define POOL_SIZE 64
26#define ISA_POOL_SIZE 16
27
28static mempool_t *page_pool, *isa_page_pool;
29
Chris Metcalff1006252012-06-16 16:41:05 -040030#if defined(CONFIG_HIGHMEM) || defined(CONFIG_NEED_BOUNCE_POOL)
David Howells831058d2006-08-29 19:06:00 +010031static __init int init_emergency_pool(void)
32{
Chris Metcalff1006252012-06-16 16:41:05 -040033#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
David Vrabel3bcfeaf2011-10-20 21:24:30 +020034 if (max_pfn <= max_low_pfn)
David Howells831058d2006-08-29 19:06:00 +010035 return 0;
David Vrabel3bcfeaf2011-10-20 21:24:30 +020036#endif
David Howells831058d2006-08-29 19:06:00 +010037
38 page_pool = mempool_create_page_pool(POOL_SIZE, 0);
39 BUG_ON(!page_pool);
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -070040 pr_info("pool size: %d pages\n", POOL_SIZE);
David Howells831058d2006-08-29 19:06:00 +010041
42 return 0;
43}
44
45__initcall(init_emergency_pool);
Chris Metcalff1006252012-06-16 16:41:05 -040046#endif
David Howells831058d2006-08-29 19:06:00 +010047
Chris Metcalff1006252012-06-16 16:41:05 -040048#ifdef CONFIG_HIGHMEM
David Howells831058d2006-08-29 19:06:00 +010049/*
50 * highmem version, map in to vec
51 */
52static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
53{
54 unsigned long flags;
55 unsigned char *vto;
56
57 local_irq_save(flags);
Cong Wang9b04c5f2011-11-25 23:14:39 +080058 vto = kmap_atomic(to->bv_page);
David Howells831058d2006-08-29 19:06:00 +010059 memcpy(vto + to->bv_offset, vfrom, to->bv_len);
Cong Wang9b04c5f2011-11-25 23:14:39 +080060 kunmap_atomic(vto);
David Howells831058d2006-08-29 19:06:00 +010061 local_irq_restore(flags);
62}
63
64#else /* CONFIG_HIGHMEM */
65
66#define bounce_copy_vec(to, vfrom) \
67 memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
68
69#endif /* CONFIG_HIGHMEM */
70
71/*
72 * allocate pages in the DMA region for the ISA pool
73 */
74static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
75{
76 return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
77}
78
79/*
80 * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
81 * as the max address, so check if the pool has already been created.
82 */
83int init_emergency_isa_pool(void)
84{
85 if (isa_page_pool)
86 return 0;
87
88 isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
89 mempool_free_pages, (void *) 0);
90 BUG_ON(!isa_page_pool);
91
Mitchel Humpherysb1de0d12014-06-06 14:38:30 -070092 pr_info("isa pool size: %d pages\n", ISA_POOL_SIZE);
David Howells831058d2006-08-29 19:06:00 +010093 return 0;
94}
95
96/*
97 * Simple bounce buffer support for highmem pages. Depending on the
98 * queue gfp mask set, *to may or may not be a highmem page. kmap it
99 * always, it will do the Right Thing
100 */
101static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
102{
103 unsigned char *vfrom;
Kent Overstreet79886132013-11-23 17:19:00 -0800104 struct bio_vec tovec, *fromvec = from->bi_io_vec;
105 struct bvec_iter iter;
David Howells831058d2006-08-29 19:06:00 +0100106
Kent Overstreet79886132013-11-23 17:19:00 -0800107 bio_for_each_segment(tovec, to, iter) {
108 if (tovec.bv_page != fromvec->bv_page) {
109 /*
110 * fromvec->bv_offset and fromvec->bv_len might have
111 * been modified by the block layer, so use the original
112 * copy, bounce_copy_vec already uses tovec->bv_len
113 */
114 vfrom = page_address(fromvec->bv_page) +
115 tovec.bv_offset;
David Howells831058d2006-08-29 19:06:00 +0100116
Kent Overstreet79886132013-11-23 17:19:00 -0800117 bounce_copy_vec(&tovec, vfrom);
118 flush_dcache_page(tovec.bv_page);
119 }
David Howells831058d2006-08-29 19:06:00 +0100120
Kent Overstreet79886132013-11-23 17:19:00 -0800121 fromvec++;
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);
Kent Overstreet79886132013-11-23 17:19:00 -0800204 struct bio_vec *to, from;
205 struct bvec_iter iter;
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700206 unsigned i;
David Howells831058d2006-08-29 19:06:00 +0100207
Darrick J. Wong83b29442013-09-30 13:45:09 -0700208 if (force)
209 goto bounce;
Kent Overstreet79886132013-11-23 17:19:00 -0800210 bio_for_each_segment(from, *bio_orig, iter)
211 if (page_to_pfn(from.bv_page) > queue_bounce_pfn(q))
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700212 goto bounce;
David Howells831058d2006-08-29 19:06:00 +0100213
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700214 return;
215bounce:
216 bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);
217
Kent Overstreetcb34e052012-09-05 15:22:02 -0700218 bio_for_each_segment_all(to, bio, i) {
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700219 struct page *page = to->bv_page;
220
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800221 if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force)
David Howells831058d2006-08-29 19:06:00 +0100222 continue;
223
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700224 to->bv_page = mempool_alloc(pool, q->bounce_gfp);
Wang YanQing393a3392015-04-26 16:43:31 +0800225 inc_zone_page_state(to->bv_page, NR_BOUNCE);
David Howells831058d2006-08-29 19:06:00 +0100226
227 if (rw == WRITE) {
228 char *vto, *vfrom;
229
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700230 flush_dcache_page(page);
231
David Howells831058d2006-08-29 19:06:00 +0100232 vto = page_address(to->bv_page) + to->bv_offset;
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700233 vfrom = kmap_atomic(page) + to->bv_offset;
David Howells831058d2006-08-29 19:06:00 +0100234 memcpy(vto, vfrom, to->bv_len);
Kent Overstreet6bc454d2012-09-10 14:30:37 -0700235 kunmap_atomic(vfrom);
David Howells831058d2006-08-29 19:06:00 +0100236 }
237 }
238
Arnaldo Carvalho de Melo5f3ea372008-10-30 08:34:33 +0100239 trace_block_bio_bounce(q, *bio_orig);
Jens Axboec43a5082007-01-12 12:20:26 +0100240
David Howells831058d2006-08-29 19:06:00 +0100241 bio->bi_flags |= (1 << BIO_BOUNCED);
David Howells831058d2006-08-29 19:06:00 +0100242
243 if (pool == page_pool) {
244 bio->bi_end_io = bounce_end_io_write;
245 if (rw == READ)
246 bio->bi_end_io = bounce_end_io_read;
247 } else {
248 bio->bi_end_io = bounce_end_io_write_isa;
249 if (rw == READ)
250 bio->bi_end_io = bounce_end_io_read_isa;
251 }
252
253 bio->bi_private = *bio_orig;
254 *bio_orig = bio;
255}
256
Jens Axboe165125e2007-07-24 09:28:11 +0200257void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
David Howells831058d2006-08-29 19:06:00 +0100258{
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800259 int must_bounce;
David Howells831058d2006-08-29 19:06:00 +0100260 mempool_t *pool;
261
262 /*
Jens Axboebf2de6f2007-09-27 13:01:25 +0200263 * Data-less bio, nothing to bounce
264 */
Jens Axboe36144072008-08-14 13:12:15 +0200265 if (!bio_has_data(*bio_orig))
Jens Axboebf2de6f2007-09-27 13:01:25 +0200266 return;
267
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800268 must_bounce = must_snapshot_stable_pages(q, *bio_orig);
269
Jens Axboebf2de6f2007-09-27 13:01:25 +0200270 /*
David Howells831058d2006-08-29 19:06:00 +0100271 * 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)) {
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800276 if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce)
David Howells831058d2006-08-29 19:06:00 +0100277 return;
278 pool = page_pool;
279 } else {
280 BUG_ON(!isa_page_pool);
281 pool = isa_page_pool;
282 }
283
David Howells831058d2006-08-29 19:06:00 +0100284 /*
285 * slow path
286 */
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800287 __blk_queue_bounce(q, bio_orig, pool, must_bounce);
David Howells831058d2006-08-29 19:06:00 +0100288}
289
290EXPORT_SYMBOL(blk_queue_bounce);