Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tree: 055c6d49d8
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 301 lines (242 sloc) 6.639 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300
/* bounce buffer handling for block devices
*
* - Split from highmem.c
*/

#include <linux/mm.h>
#include <linux/module.h>
#include <linux/swap.h>
#include <linux/gfp.h>
#include <linux/bio.h>
#include <linux/pagemap.h>
#include <linux/mempool.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/highmem.h>
#include <asm/tlbflush.h>

#include <trace/events/block.h>

#define POOL_SIZE 64
#define ISA_POOL_SIZE 16

static mempool_t *page_pool, *isa_page_pool;

#ifdef CONFIG_HIGHMEM
static __init int init_emergency_pool(void)
{
struct sysinfo i;
si_meminfo(&i);
si_swapinfo(&i);

if (!i.totalhigh)
return 0;

page_pool = mempool_create_page_pool(POOL_SIZE, 0);
BUG_ON(!page_pool);
printk("highmem bounce pool size: %d pages\n", POOL_SIZE);

return 0;
}

__initcall(init_emergency_pool);

/*
* highmem version, map in to vec
*/
static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
{
unsigned long flags;
unsigned char *vto;

local_irq_save(flags);
vto = kmap_atomic(to->bv_page, KM_BOUNCE_READ);
memcpy(vto + to->bv_offset, vfrom, to->bv_len);
kunmap_atomic(vto, KM_BOUNCE_READ);
local_irq_restore(flags);
}

#else /* CONFIG_HIGHMEM */

#define bounce_copy_vec(to, vfrom) \
memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)

#endif /* CONFIG_HIGHMEM */

/*
* allocate pages in the DMA region for the ISA pool
*/
static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
{
return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
}

/*
* gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
* as the max address, so check if the pool has already been created.
*/
int init_emergency_isa_pool(void)
{
if (isa_page_pool)
return 0;

isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
mempool_free_pages, (void *) 0);
BUG_ON(!isa_page_pool);

printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE);
return 0;
}

/*
* Simple bounce buffer support for highmem pages. Depending on the
* queue gfp mask set, *to may or may not be a highmem page. kmap it
* always, it will do the Right Thing
*/
static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
{
unsigned char *vfrom;
struct bio_vec *tovec, *fromvec;
int i;

__bio_for_each_segment(tovec, to, i, 0) {
fromvec = from->bi_io_vec + i;

/*
* not bounced
*/
if (tovec->bv_page == fromvec->bv_page)
continue;

/*
* fromvec->bv_offset and fromvec->bv_len might have been
* modified by the block layer, so use the original copy,
* bounce_copy_vec already uses tovec->bv_len
*/
vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;

bounce_copy_vec(tovec, vfrom);
flush_dcache_page(tovec->bv_page);
}
}

static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
{
struct bio *bio_orig = bio->bi_private;
struct bio_vec *bvec, *org_vec;
int i;

if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);

/*
* free up bounce indirect pages used
*/
__bio_for_each_segment(bvec, bio, i, 0) {
org_vec = bio_orig->bi_io_vec + i;
if (bvec->bv_page == org_vec->bv_page)
continue;

dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
mempool_free(bvec->bv_page, pool);
}

bio_endio(bio_orig, err);
bio_put(bio);
}

static void bounce_end_io_write(struct bio *bio, int err)
{
bounce_end_io(bio, page_pool, err);
}

static void bounce_end_io_write_isa(struct bio *bio, int err)
{

bounce_end_io(bio, isa_page_pool, err);
}

static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
{
struct bio *bio_orig = bio->bi_private;

if (test_bit(BIO_UPTODATE, &bio->bi_flags))
copy_to_high_bio_irq(bio_orig, bio);

bounce_end_io(bio, pool, err);
}

static void bounce_end_io_read(struct bio *bio, int err)
{
__bounce_end_io_read(bio, page_pool, err);
}

static void bounce_end_io_read_isa(struct bio *bio, int err)
{
__bounce_end_io_read(bio, isa_page_pool, err);
}

static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
mempool_t *pool)
{
struct page *page;
struct bio *bio = NULL;
int i, rw = bio_data_dir(*bio_orig);
struct bio_vec *to, *from;

bio_for_each_segment(from, *bio_orig, i) {
page = from->bv_page;

/*
* is destination page below bounce pfn?
*/
if (page_to_pfn(page) <= queue_bounce_pfn(q))
continue;

/*
* irk, bounce it
*/
if (!bio) {
unsigned int cnt = (*bio_orig)->bi_vcnt;

bio = bio_alloc(GFP_NOIO, cnt);
memset(bio->bi_io_vec, 0, cnt * sizeof(struct bio_vec));
}


to = bio->bi_io_vec + i;

to->bv_page = mempool_alloc(pool, q->bounce_gfp);
to->bv_len = from->bv_len;
to->bv_offset = from->bv_offset;
inc_zone_page_state(to->bv_page, NR_BOUNCE);

if (rw == WRITE) {
char *vto, *vfrom;

flush_dcache_page(from->bv_page);
vto = page_address(to->bv_page) + to->bv_offset;
vfrom = kmap(from->bv_page) + from->bv_offset;
memcpy(vto, vfrom, to->bv_len);
kunmap(from->bv_page);
}
}

/*
* no pages bounced
*/
if (!bio)
return;

trace_block_bio_bounce(q, *bio_orig);

/*
* at least one page was bounced, fill in possible non-highmem
* pages
*/
__bio_for_each_segment(from, *bio_orig, i, 0) {
to = bio_iovec_idx(bio, i);
if (!to->bv_page) {
to->bv_page = from->bv_page;
to->bv_len = from->bv_len;
to->bv_offset = from->bv_offset;
}
}

bio->bi_bdev = (*bio_orig)->bi_bdev;
bio->bi_flags |= (1 << BIO_BOUNCED);
bio->bi_sector = (*bio_orig)->bi_sector;
bio->bi_rw = (*bio_orig)->bi_rw;

bio->bi_vcnt = (*bio_orig)->bi_vcnt;
bio->bi_idx = (*bio_orig)->bi_idx;
bio->bi_size = (*bio_orig)->bi_size;

if (pool == page_pool) {
bio->bi_end_io = bounce_end_io_write;
if (rw == READ)
bio->bi_end_io = bounce_end_io_read;
} else {
bio->bi_end_io = bounce_end_io_write_isa;
if (rw == READ)
bio->bi_end_io = bounce_end_io_read_isa;
}

bio->bi_private = *bio_orig;
*bio_orig = bio;
}

void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
{
mempool_t *pool;

/*
* Data-less bio, nothing to bounce
*/
if (!bio_has_data(*bio_orig))
return;

/*
* for non-isa bounce case, just check if the bounce pfn is equal
* to or bigger than the highest pfn in the system -- in that case,
* don't waste time iterating over bio segments
*/
if (!(q->bounce_gfp & GFP_DMA)) {
if (queue_bounce_pfn(q) >= blk_max_pfn)
return;
pool = page_pool;
} else {
BUG_ON(!isa_page_pool);
pool = isa_page_pool;
}

/*
* slow path
*/
__blk_queue_bounce(q, bio_orig, pool);
}

EXPORT_SYMBOL(blk_queue_bounce);
Something went wrong with that request. Please try again.