1719c555fSJens Axboe /* bounce buffer handling for block devices 2719c555fSJens Axboe * 3719c555fSJens Axboe * - Split from highmem.c 4719c555fSJens Axboe */ 5719c555fSJens Axboe 6719c555fSJens Axboe #include <linux/mm.h> 7719c555fSJens Axboe #include <linux/export.h> 8719c555fSJens Axboe #include <linux/swap.h> 9719c555fSJens Axboe #include <linux/gfp.h> 10719c555fSJens Axboe #include <linux/bio.h> 11719c555fSJens Axboe #include <linux/pagemap.h> 12719c555fSJens Axboe #include <linux/mempool.h> 13719c555fSJens Axboe #include <linux/blkdev.h> 14719c555fSJens Axboe #include <linux/init.h> 15719c555fSJens Axboe #include <linux/hash.h> 16719c555fSJens Axboe #include <linux/highmem.h> 17719c555fSJens Axboe #include <linux/bootmem.h> 18719c555fSJens Axboe #include <asm/tlbflush.h> 19719c555fSJens Axboe 20719c555fSJens Axboe #include <trace/events/block.h> 21719c555fSJens Axboe 22719c555fSJens Axboe #define POOL_SIZE 64 23719c555fSJens Axboe #define ISA_POOL_SIZE 16 24719c555fSJens Axboe 25719c555fSJens Axboe static mempool_t *page_pool, *isa_page_pool; 26719c555fSJens Axboe 27719c555fSJens Axboe #if defined(CONFIG_HIGHMEM) || defined(CONFIG_NEED_BOUNCE_POOL) 28719c555fSJens Axboe static __init int init_emergency_pool(void) 29719c555fSJens Axboe { 30719c555fSJens Axboe #if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG) 31719c555fSJens Axboe if (max_pfn <= max_low_pfn) 32719c555fSJens Axboe return 0; 33719c555fSJens Axboe #endif 34719c555fSJens Axboe 35719c555fSJens Axboe page_pool = mempool_create_page_pool(POOL_SIZE, 0); 36719c555fSJens Axboe BUG_ON(!page_pool); 37719c555fSJens Axboe printk("bounce pool size: %d pages\n", POOL_SIZE); 38719c555fSJens Axboe 39719c555fSJens Axboe return 0; 40719c555fSJens Axboe } 41719c555fSJens Axboe 42719c555fSJens Axboe __initcall(init_emergency_pool); 43719c555fSJens Axboe #endif 44719c555fSJens Axboe 45719c555fSJens Axboe #ifdef CONFIG_HIGHMEM 46719c555fSJens Axboe /* 47719c555fSJens Axboe * highmem version, map in to vec 48719c555fSJens Axboe */ 49719c555fSJens Axboe static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom) 50719c555fSJens Axboe { 51719c555fSJens Axboe unsigned long flags; 52719c555fSJens Axboe unsigned char *vto; 53719c555fSJens Axboe 54719c555fSJens Axboe local_irq_save(flags); 55719c555fSJens Axboe vto = kmap_atomic(to->bv_page); 56719c555fSJens Axboe memcpy(vto + to->bv_offset, vfrom, to->bv_len); 57719c555fSJens Axboe kunmap_atomic(vto); 58719c555fSJens Axboe local_irq_restore(flags); 59719c555fSJens Axboe } 60719c555fSJens Axboe 61719c555fSJens Axboe #else /* CONFIG_HIGHMEM */ 62719c555fSJens Axboe 63719c555fSJens Axboe #define bounce_copy_vec(to, vfrom) \ 64719c555fSJens Axboe memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len) 65719c555fSJens Axboe 66719c555fSJens Axboe #endif /* CONFIG_HIGHMEM */ 67719c555fSJens Axboe 68719c555fSJens Axboe /* 69719c555fSJens Axboe * allocate pages in the DMA region for the ISA pool 70719c555fSJens Axboe */ 71719c555fSJens Axboe static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data) 72719c555fSJens Axboe { 73719c555fSJens Axboe return mempool_alloc_pages(gfp_mask | GFP_DMA, data); 74719c555fSJens Axboe } 75719c555fSJens Axboe 76719c555fSJens Axboe /* 77719c555fSJens Axboe * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA 78719c555fSJens Axboe * as the max address, so check if the pool has already been created. 79719c555fSJens Axboe */ 80719c555fSJens Axboe int init_emergency_isa_pool(void) 81719c555fSJens Axboe { 82719c555fSJens Axboe if (isa_page_pool) 83719c555fSJens Axboe return 0; 84719c555fSJens Axboe 85719c555fSJens Axboe isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa, 86719c555fSJens Axboe mempool_free_pages, (void *) 0); 87719c555fSJens Axboe BUG_ON(!isa_page_pool); 88719c555fSJens Axboe 89719c555fSJens Axboe printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE); 90719c555fSJens Axboe return 0; 91719c555fSJens Axboe } 92719c555fSJens Axboe 93719c555fSJens Axboe /* 94719c555fSJens Axboe * Simple bounce buffer support for highmem pages. Depending on the 95719c555fSJens Axboe * queue gfp mask set, *to may or may not be a highmem page. kmap it 96719c555fSJens Axboe * always, it will do the Right Thing 97719c555fSJens Axboe */ 98719c555fSJens Axboe static void copy_to_high_bio_irq(struct bio *to, struct bio *from) 99719c555fSJens Axboe { 100719c555fSJens Axboe unsigned char *vfrom; 101719c555fSJens Axboe struct bio_vec tovec, *fromvec = from->bi_io_vec; 102719c555fSJens Axboe struct bvec_iter iter; 103719c555fSJens Axboe 104719c555fSJens Axboe bio_for_each_segment(tovec, to, iter) { 105719c555fSJens Axboe if (tovec.bv_page != fromvec->bv_page) { 106719c555fSJens Axboe /* 107719c555fSJens Axboe * fromvec->bv_offset and fromvec->bv_len might have 108719c555fSJens Axboe * been modified by the block layer, so use the original 109719c555fSJens Axboe * copy, bounce_copy_vec already uses tovec->bv_len 110719c555fSJens Axboe */ 111719c555fSJens Axboe vfrom = page_address(fromvec->bv_page) + 112719c555fSJens Axboe tovec.bv_offset; 113719c555fSJens Axboe 114719c555fSJens Axboe bounce_copy_vec(&tovec, vfrom); 115719c555fSJens Axboe flush_dcache_page(tovec.bv_page); 116719c555fSJens Axboe } 117719c555fSJens Axboe 118719c555fSJens Axboe fromvec++; 119719c555fSJens Axboe } 120719c555fSJens Axboe } 121719c555fSJens Axboe 122719c555fSJens Axboe static void bounce_end_io(struct bio *bio, mempool_t *pool, int err) 123719c555fSJens Axboe { 124719c555fSJens Axboe struct bio *bio_orig = bio->bi_private; 125719c555fSJens Axboe struct bio_vec *bvec, *org_vec; 126719c555fSJens Axboe int i; 127719c555fSJens Axboe 128719c555fSJens Axboe if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags)) 129719c555fSJens Axboe set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags); 130719c555fSJens Axboe 131719c555fSJens Axboe /* 132719c555fSJens Axboe * free up bounce indirect pages used 133719c555fSJens Axboe */ 134719c555fSJens Axboe bio_for_each_segment_all(bvec, bio, i) { 135719c555fSJens Axboe org_vec = bio_orig->bi_io_vec + i; 136719c555fSJens Axboe if (bvec->bv_page == org_vec->bv_page) 137719c555fSJens Axboe continue; 138719c555fSJens Axboe 139719c555fSJens Axboe dec_zone_page_state(bvec->bv_page, NR_BOUNCE); 140719c555fSJens Axboe mempool_free(bvec->bv_page, pool); 141719c555fSJens Axboe } 142719c555fSJens Axboe 143719c555fSJens Axboe bio_endio(bio_orig, err); 144719c555fSJens Axboe bio_put(bio); 145719c555fSJens Axboe } 146719c555fSJens Axboe 147719c555fSJens Axboe static void bounce_end_io_write(struct bio *bio, int err) 148719c555fSJens Axboe { 149719c555fSJens Axboe bounce_end_io(bio, page_pool, err); 150719c555fSJens Axboe } 151719c555fSJens Axboe 152719c555fSJens Axboe static void bounce_end_io_write_isa(struct bio *bio, int err) 153719c555fSJens Axboe { 154719c555fSJens Axboe 155719c555fSJens Axboe bounce_end_io(bio, isa_page_pool, err); 156719c555fSJens Axboe } 157719c555fSJens Axboe 158719c555fSJens Axboe static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err) 159719c555fSJens Axboe { 160719c555fSJens Axboe struct bio *bio_orig = bio->bi_private; 161719c555fSJens Axboe 162719c555fSJens Axboe if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 163719c555fSJens Axboe copy_to_high_bio_irq(bio_orig, bio); 164719c555fSJens Axboe 165719c555fSJens Axboe bounce_end_io(bio, pool, err); 166719c555fSJens Axboe } 167719c555fSJens Axboe 168719c555fSJens Axboe static void bounce_end_io_read(struct bio *bio, int err) 169719c555fSJens Axboe { 170719c555fSJens Axboe __bounce_end_io_read(bio, page_pool, err); 171719c555fSJens Axboe } 172719c555fSJens Axboe 173719c555fSJens Axboe static void bounce_end_io_read_isa(struct bio *bio, int err) 174719c555fSJens Axboe { 175719c555fSJens Axboe __bounce_end_io_read(bio, isa_page_pool, err); 176719c555fSJens Axboe } 177719c555fSJens Axboe 178719c555fSJens Axboe #ifdef CONFIG_NEED_BOUNCE_POOL 179719c555fSJens Axboe static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio) 180719c555fSJens Axboe { 181719c555fSJens Axboe if (bio_data_dir(bio) != WRITE) 182719c555fSJens Axboe return 0; 183719c555fSJens Axboe 184719c555fSJens Axboe if (!bdi_cap_stable_pages_required(&q->backing_dev_info)) 185719c555fSJens Axboe return 0; 186719c555fSJens Axboe 187719c555fSJens Axboe return test_bit(BIO_SNAP_STABLE, &bio->bi_flags); 188719c555fSJens Axboe } 189719c555fSJens Axboe #else 190719c555fSJens Axboe static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio) 191719c555fSJens Axboe { 192719c555fSJens Axboe return 0; 193719c555fSJens Axboe } 194719c555fSJens Axboe #endif /* CONFIG_NEED_BOUNCE_POOL */ 195719c555fSJens Axboe 196719c555fSJens Axboe static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, 197719c555fSJens Axboe mempool_t *pool, int force) 198719c555fSJens Axboe { 199719c555fSJens Axboe struct bio *bio; 200719c555fSJens Axboe int rw = bio_data_dir(*bio_orig); 201719c555fSJens Axboe struct bio_vec *to, from; 202719c555fSJens Axboe struct bvec_iter iter; 203719c555fSJens Axboe unsigned i; 204719c555fSJens Axboe 205719c555fSJens Axboe if (force) 206719c555fSJens Axboe goto bounce; 207719c555fSJens Axboe bio_for_each_segment(from, *bio_orig, iter) 208719c555fSJens Axboe if (page_to_pfn(from.bv_page) > queue_bounce_pfn(q)) 209719c555fSJens Axboe goto bounce; 210719c555fSJens Axboe 211719c555fSJens Axboe return; 212719c555fSJens Axboe bounce: 213719c555fSJens Axboe bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set); 214719c555fSJens Axboe 215719c555fSJens Axboe bio_for_each_segment_all(to, bio, i) { 216719c555fSJens Axboe struct page *page = to->bv_page; 217719c555fSJens Axboe 218719c555fSJens Axboe if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force) 219719c555fSJens Axboe continue; 220719c555fSJens Axboe 221719c555fSJens Axboe inc_zone_page_state(to->bv_page, NR_BOUNCE); 222719c555fSJens Axboe to->bv_page = mempool_alloc(pool, q->bounce_gfp); 223719c555fSJens Axboe 224719c555fSJens Axboe if (rw == WRITE) { 225719c555fSJens Axboe char *vto, *vfrom; 226719c555fSJens Axboe 227719c555fSJens Axboe flush_dcache_page(page); 228719c555fSJens Axboe 229719c555fSJens Axboe vto = page_address(to->bv_page) + to->bv_offset; 230719c555fSJens Axboe vfrom = kmap_atomic(page) + to->bv_offset; 231719c555fSJens Axboe memcpy(vto, vfrom, to->bv_len); 232719c555fSJens Axboe kunmap_atomic(vfrom); 233719c555fSJens Axboe } 234719c555fSJens Axboe } 235719c555fSJens Axboe 236719c555fSJens Axboe trace_block_bio_bounce(q, *bio_orig); 237719c555fSJens Axboe 238719c555fSJens Axboe bio->bi_flags |= (1 << BIO_BOUNCED); 239719c555fSJens Axboe 240719c555fSJens Axboe if (pool == page_pool) { 241719c555fSJens Axboe bio->bi_end_io = bounce_end_io_write; 242719c555fSJens Axboe if (rw == READ) 243719c555fSJens Axboe bio->bi_end_io = bounce_end_io_read; 244719c555fSJens Axboe } else { 245719c555fSJens Axboe bio->bi_end_io = bounce_end_io_write_isa; 246719c555fSJens Axboe if (rw == READ) 247719c555fSJens Axboe bio->bi_end_io = bounce_end_io_read_isa; 248719c555fSJens Axboe } 249719c555fSJens Axboe 250719c555fSJens Axboe bio->bi_private = *bio_orig; 251719c555fSJens Axboe *bio_orig = bio; 252719c555fSJens Axboe } 253719c555fSJens Axboe 254719c555fSJens Axboe void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) 255719c555fSJens Axboe { 256719c555fSJens Axboe int must_bounce; 257719c555fSJens Axboe mempool_t *pool; 258719c555fSJens Axboe 259719c555fSJens Axboe /* 260719c555fSJens Axboe * Data-less bio, nothing to bounce 261719c555fSJens Axboe */ 262719c555fSJens Axboe if (!bio_has_data(*bio_orig)) 263719c555fSJens Axboe return; 264719c555fSJens Axboe 265719c555fSJens Axboe must_bounce = must_snapshot_stable_pages(q, *bio_orig); 266719c555fSJens Axboe 267719c555fSJens Axboe /* 268719c555fSJens Axboe * for non-isa bounce case, just check if the bounce pfn is equal 269719c555fSJens Axboe * to or bigger than the highest pfn in the system -- in that case, 270719c555fSJens Axboe * don't waste time iterating over bio segments 271719c555fSJens Axboe */ 272719c555fSJens Axboe if (!(q->bounce_gfp & GFP_DMA)) { 273719c555fSJens Axboe if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce) 274719c555fSJens Axboe return; 275719c555fSJens Axboe pool = page_pool; 276719c555fSJens Axboe } else { 277719c555fSJens Axboe BUG_ON(!isa_page_pool); 278719c555fSJens Axboe pool = isa_page_pool; 279719c555fSJens Axboe } 280719c555fSJens Axboe 281719c555fSJens Axboe /* 282719c555fSJens Axboe * slow path 283719c555fSJens Axboe */ 284719c555fSJens Axboe __blk_queue_bounce(q, bio_orig, pool, must_bounce); 285719c555fSJens Axboe } 286719c555fSJens Axboe 287719c555fSJens Axboe EXPORT_SYMBOL(blk_queue_bounce); 288