1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 2719c555fSJens Axboe /* bounce buffer handling for block devices 3719c555fSJens Axboe * 4719c555fSJens Axboe * - Split from highmem.c 5719c555fSJens Axboe */ 6719c555fSJens Axboe 7b1de0d13SMitchel Humpherys #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 8b1de0d13SMitchel Humpherys 9719c555fSJens Axboe #include <linux/mm.h> 10719c555fSJens Axboe #include <linux/export.h> 11719c555fSJens Axboe #include <linux/swap.h> 12719c555fSJens Axboe #include <linux/gfp.h> 13719c555fSJens Axboe #include <linux/bio.h> 14719c555fSJens Axboe #include <linux/pagemap.h> 15719c555fSJens Axboe #include <linux/mempool.h> 16719c555fSJens Axboe #include <linux/blkdev.h> 1766114cadSTejun Heo #include <linux/backing-dev.h> 18719c555fSJens Axboe #include <linux/init.h> 19719c555fSJens Axboe #include <linux/hash.h> 20719c555fSJens Axboe #include <linux/highmem.h> 21b1de0d13SMitchel Humpherys #include <linux/printk.h> 22719c555fSJens Axboe #include <asm/tlbflush.h> 23719c555fSJens Axboe 24719c555fSJens Axboe #include <trace/events/block.h> 253bce016aSChristoph Hellwig #include "blk.h" 26719c555fSJens Axboe 27719c555fSJens Axboe #define POOL_SIZE 64 28719c555fSJens Axboe #define ISA_POOL_SIZE 16 29719c555fSJens Axboe 30338aa96dSKent Overstreet static struct bio_set bounce_bio_set, bounce_bio_split; 31ce288e05SChristoph Hellwig static mempool_t page_pool; 32719c555fSJens Axboe 3352990a5fSJens Axboe static void init_bounce_bioset(void) 3452990a5fSJens Axboe { 3552990a5fSJens Axboe static bool bounce_bs_setup; 3652990a5fSJens Axboe int ret; 3752990a5fSJens Axboe 3852990a5fSJens Axboe if (bounce_bs_setup) 3952990a5fSJens Axboe return; 4052990a5fSJens Axboe 4152990a5fSJens Axboe ret = bioset_init(&bounce_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS); 4252990a5fSJens Axboe BUG_ON(ret); 4352990a5fSJens Axboe if (bioset_integrity_create(&bounce_bio_set, BIO_POOL_SIZE)) 4452990a5fSJens Axboe BUG_ON(1); 4552990a5fSJens Axboe 4652990a5fSJens Axboe ret = bioset_init(&bounce_bio_split, BIO_POOL_SIZE, 0, 0); 4752990a5fSJens Axboe BUG_ON(ret); 4852990a5fSJens Axboe bounce_bs_setup = true; 4952990a5fSJens Axboe } 5052990a5fSJens Axboe 51719c555fSJens Axboe static __init int init_emergency_pool(void) 52719c555fSJens Axboe { 53338aa96dSKent Overstreet int ret; 549bb33f24SChristoph Hellwig 559bb33f24SChristoph Hellwig #ifndef CONFIG_MEMORY_HOTPLUG 56719c555fSJens Axboe if (max_pfn <= max_low_pfn) 57719c555fSJens Axboe return 0; 58719c555fSJens Axboe #endif 59719c555fSJens Axboe 60338aa96dSKent Overstreet ret = mempool_init_page_pool(&page_pool, POOL_SIZE, 0); 61338aa96dSKent Overstreet BUG_ON(ret); 62b1de0d13SMitchel Humpherys pr_info("pool size: %d pages\n", POOL_SIZE); 63719c555fSJens Axboe 6452990a5fSJens Axboe init_bounce_bioset(); 65719c555fSJens Axboe return 0; 66719c555fSJens Axboe } 67719c555fSJens Axboe 68719c555fSJens Axboe __initcall(init_emergency_pool); 69719c555fSJens Axboe 70719c555fSJens Axboe /* 71719c555fSJens Axboe * Simple bounce buffer support for highmem pages. Depending on the 72719c555fSJens Axboe * queue gfp mask set, *to may or may not be a highmem page. kmap it 73719c555fSJens Axboe * always, it will do the Right Thing 74719c555fSJens Axboe */ 75719c555fSJens Axboe static void copy_to_high_bio_irq(struct bio *to, struct bio *from) 76719c555fSJens Axboe { 773c892a09SMing Lei struct bio_vec tovec, fromvec; 78719c555fSJens Axboe struct bvec_iter iter; 793c892a09SMing Lei /* 803c892a09SMing Lei * The bio of @from is created by bounce, so we can iterate 813c892a09SMing Lei * its bvec from start to end, but the @from->bi_iter can't be 823c892a09SMing Lei * trusted because it might be changed by splitting. 833c892a09SMing Lei */ 843c892a09SMing Lei struct bvec_iter from_iter = BVEC_ITER_ALL_INIT; 85719c555fSJens Axboe 86719c555fSJens Axboe bio_for_each_segment(tovec, to, iter) { 873c892a09SMing Lei fromvec = bio_iter_iovec(from, from_iter); 883c892a09SMing Lei if (tovec.bv_page != fromvec.bv_page) { 89719c555fSJens Axboe /* 90719c555fSJens Axboe * fromvec->bv_offset and fromvec->bv_len might have 91719c555fSJens Axboe * been modified by the block layer, so use the original 92719c555fSJens Axboe * copy, bounce_copy_vec already uses tovec->bv_len 93719c555fSJens Axboe */ 94f434cdc7SChristoph Hellwig memcpy_to_bvec(&tovec, page_address(fromvec.bv_page) + 95f434cdc7SChristoph Hellwig tovec.bv_offset); 96719c555fSJens Axboe } 973c892a09SMing Lei bio_advance_iter(from, &from_iter, tovec.bv_len); 98719c555fSJens Axboe } 99719c555fSJens Axboe } 100719c555fSJens Axboe 101ce288e05SChristoph Hellwig static void bounce_end_io(struct bio *bio) 102719c555fSJens Axboe { 103719c555fSJens Axboe struct bio *bio_orig = bio->bi_private; 1047891f05cSMing Lei struct bio_vec *bvec, orig_vec; 1057891f05cSMing Lei struct bvec_iter orig_iter = bio_orig->bi_iter; 1066dc4f100SMing Lei struct bvec_iter_all iter_all; 107719c555fSJens Axboe 108719c555fSJens Axboe /* 109719c555fSJens Axboe * free up bounce indirect pages used 110719c555fSJens Axboe */ 1112b070cfeSChristoph Hellwig bio_for_each_segment_all(bvec, bio, iter_all) { 1127891f05cSMing Lei orig_vec = bio_iter_iovec(bio_orig, orig_iter); 1137891f05cSMing Lei if (bvec->bv_page != orig_vec.bv_page) { 114719c555fSJens Axboe dec_zone_page_state(bvec->bv_page, NR_BOUNCE); 115ce288e05SChristoph Hellwig mempool_free(bvec->bv_page, &page_pool); 116719c555fSJens Axboe } 1177891f05cSMing Lei bio_advance_iter(bio_orig, &orig_iter, orig_vec.bv_len); 1187891f05cSMing Lei } 119719c555fSJens Axboe 1204e4cbee9SChristoph Hellwig bio_orig->bi_status = bio->bi_status; 1214246a0b6SChristoph Hellwig bio_endio(bio_orig); 122719c555fSJens Axboe bio_put(bio); 123719c555fSJens Axboe } 124719c555fSJens Axboe 1254246a0b6SChristoph Hellwig static void bounce_end_io_write(struct bio *bio) 126719c555fSJens Axboe { 127ce288e05SChristoph Hellwig bounce_end_io(bio); 128719c555fSJens Axboe } 129719c555fSJens Axboe 130ce288e05SChristoph Hellwig static void bounce_end_io_read(struct bio *bio) 131719c555fSJens Axboe { 132719c555fSJens Axboe struct bio *bio_orig = bio->bi_private; 133719c555fSJens Axboe 1344e4cbee9SChristoph Hellwig if (!bio->bi_status) 135719c555fSJens Axboe copy_to_high_bio_irq(bio_orig, bio); 136719c555fSJens Axboe 137ce288e05SChristoph Hellwig bounce_end_io(bio); 138719c555fSJens Axboe } 139719c555fSJens Axboe 140ebfe4183SChristoph Hellwig static struct bio *bounce_clone_bio(struct bio *bio_src) 141c55183c9SChristoph Hellwig { 142c55183c9SChristoph Hellwig struct bvec_iter iter; 143c55183c9SChristoph Hellwig struct bio_vec bv; 144c55183c9SChristoph Hellwig struct bio *bio; 145c55183c9SChristoph Hellwig 146c55183c9SChristoph Hellwig /* 147c55183c9SChristoph Hellwig * Pre immutable biovecs, __bio_clone() used to just do a memcpy from 148c55183c9SChristoph Hellwig * bio_src->bi_io_vec to bio->bi_io_vec. 149c55183c9SChristoph Hellwig * 150c55183c9SChristoph Hellwig * We can't do that anymore, because: 151c55183c9SChristoph Hellwig * 152c55183c9SChristoph Hellwig * - The point of cloning the biovec is to produce a bio with a biovec 153c55183c9SChristoph Hellwig * the caller can modify: bi_idx and bi_bvec_done should be 0. 154c55183c9SChristoph Hellwig * 155a8affc03SChristoph Hellwig * - The original bio could've had more than BIO_MAX_VECS biovecs; if 156c55183c9SChristoph Hellwig * we tried to clone the whole thing bio_alloc_bioset() would fail. 157c55183c9SChristoph Hellwig * But the clone should succeed as long as the number of biovecs we 158a8affc03SChristoph Hellwig * actually need to allocate is fewer than BIO_MAX_VECS. 159c55183c9SChristoph Hellwig * 160c55183c9SChristoph Hellwig * - Lastly, bi_vcnt should not be looked at or relied upon by code 161c55183c9SChristoph Hellwig * that does not own the bio - reason being drivers don't use it for 162c55183c9SChristoph Hellwig * iterating over the biovec anymore, so expecting it to be kept up 163c55183c9SChristoph Hellwig * to date (i.e. for clones that share the parent biovec) is just 164c55183c9SChristoph Hellwig * asking for trouble and would force extra work on 165c55183c9SChristoph Hellwig * __bio_clone_fast() anyways. 166c55183c9SChristoph Hellwig */ 167ebfe4183SChristoph Hellwig bio = bio_alloc_bioset(GFP_NOIO, bio_segments(bio_src), 168b90994c6SChristoph Hellwig &bounce_bio_set); 169309dca30SChristoph Hellwig bio->bi_bdev = bio_src->bi_bdev; 17046bbf653SChristoph Hellwig if (bio_flagged(bio_src, BIO_REMAPPED)) 17146bbf653SChristoph Hellwig bio_set_flag(bio, BIO_REMAPPED); 172c55183c9SChristoph Hellwig bio->bi_opf = bio_src->bi_opf; 173ca474b73SHannes Reinecke bio->bi_ioprio = bio_src->bi_ioprio; 174c55183c9SChristoph Hellwig bio->bi_write_hint = bio_src->bi_write_hint; 175c55183c9SChristoph Hellwig bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector; 176c55183c9SChristoph Hellwig bio->bi_iter.bi_size = bio_src->bi_iter.bi_size; 177c55183c9SChristoph Hellwig 178c55183c9SChristoph Hellwig switch (bio_op(bio)) { 179c55183c9SChristoph Hellwig case REQ_OP_DISCARD: 180c55183c9SChristoph Hellwig case REQ_OP_SECURE_ERASE: 181c55183c9SChristoph Hellwig case REQ_OP_WRITE_ZEROES: 182c55183c9SChristoph Hellwig break; 183c55183c9SChristoph Hellwig case REQ_OP_WRITE_SAME: 184c55183c9SChristoph Hellwig bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0]; 185c55183c9SChristoph Hellwig break; 186c55183c9SChristoph Hellwig default: 187c55183c9SChristoph Hellwig bio_for_each_segment(bv, bio_src, iter) 188c55183c9SChristoph Hellwig bio->bi_io_vec[bio->bi_vcnt++] = bv; 189c55183c9SChristoph Hellwig break; 190c55183c9SChristoph Hellwig } 191c55183c9SChristoph Hellwig 192ebfe4183SChristoph Hellwig if (bio_crypt_clone(bio, bio_src, GFP_NOIO) < 0) 19307560151SEric Biggers goto err_put; 194a892c8d5SSatya Tangirala 19507560151SEric Biggers if (bio_integrity(bio_src) && 196ebfe4183SChristoph Hellwig bio_integrity_clone(bio, bio_src, GFP_NOIO) < 0) 19707560151SEric Biggers goto err_put; 198c55183c9SChristoph Hellwig 199db6638d7SDennis Zhou bio_clone_blkg_association(bio, bio_src); 200e439bedfSDennis Zhou blkcg_bio_issue_init(bio); 2015bf9a1f3SDennis Zhou (Facebook) 202c55183c9SChristoph Hellwig return bio; 20307560151SEric Biggers 20407560151SEric Biggers err_put: 20507560151SEric Biggers bio_put(bio); 20607560151SEric Biggers return NULL; 207c55183c9SChristoph Hellwig } 208c55183c9SChristoph Hellwig 2099bb33f24SChristoph Hellwig void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) 210719c555fSJens Axboe { 211719c555fSJens Axboe struct bio *bio; 212719c555fSJens Axboe int rw = bio_data_dir(*bio_orig); 213719c555fSJens Axboe struct bio_vec *to, from; 214719c555fSJens Axboe struct bvec_iter iter; 215a8821f3fSNeilBrown unsigned i = 0; 216a8821f3fSNeilBrown bool bounce = false; 217a8821f3fSNeilBrown int sectors = 0; 218719c555fSJens Axboe 219a8821f3fSNeilBrown bio_for_each_segment(from, *bio_orig, iter) { 220a8affc03SChristoph Hellwig if (i++ < BIO_MAX_VECS) 221a8821f3fSNeilBrown sectors += from.bv_len >> 9; 2229bb33f24SChristoph Hellwig if (PageHighMem(from.bv_page)) 223a8821f3fSNeilBrown bounce = true; 224a8821f3fSNeilBrown } 225a8821f3fSNeilBrown if (!bounce) 226719c555fSJens Axboe return; 227a8821f3fSNeilBrown 228393bb12eSChristoph Hellwig if (sectors < bio_sectors(*bio_orig)) { 229338aa96dSKent Overstreet bio = bio_split(*bio_orig, sectors, GFP_NOIO, &bounce_bio_split); 230a8821f3fSNeilBrown bio_chain(bio, *bio_orig); 231ed00aabdSChristoph Hellwig submit_bio_noacct(*bio_orig); 232a8821f3fSNeilBrown *bio_orig = bio; 233a8821f3fSNeilBrown } 234ebfe4183SChristoph Hellwig bio = bounce_clone_bio(*bio_orig); 235719c555fSJens Axboe 2368f4e80daSMing Lei /* 2378f4e80daSMing Lei * Bvec table can't be updated by bio_for_each_segment_all(), 2388f4e80daSMing Lei * so retrieve bvec from the table directly. This way is safe 2398f4e80daSMing Lei * because the 'bio' is single-page bvec. 2408f4e80daSMing Lei */ 2418f4e80daSMing Lei for (i = 0, to = bio->bi_io_vec; i < bio->bi_vcnt; to++, i++) { 242*4aebe859SChristoph Hellwig struct page *bounce_page; 243719c555fSJens Axboe 244*4aebe859SChristoph Hellwig if (!PageHighMem(to->bv_page)) 245719c555fSJens Axboe continue; 246719c555fSJens Axboe 247*4aebe859SChristoph Hellwig bounce_page = mempool_alloc(&page_pool, GFP_NOIO); 248*4aebe859SChristoph Hellwig inc_zone_page_state(bounce_page, NR_BOUNCE); 249719c555fSJens Axboe 250719c555fSJens Axboe if (rw == WRITE) { 251*4aebe859SChristoph Hellwig flush_dcache_page(to->bv_page); 252*4aebe859SChristoph Hellwig memcpy_from_bvec(page_address(bounce_page), to); 253719c555fSJens Axboe } 254*4aebe859SChristoph Hellwig to->bv_page = bounce_page; 255719c555fSJens Axboe } 256719c555fSJens Axboe 257e8a676d6SChristoph Hellwig trace_block_bio_bounce(*bio_orig); 258719c555fSJens Axboe 259719c555fSJens Axboe bio->bi_flags |= (1 << BIO_BOUNCED); 260719c555fSJens Axboe 261719c555fSJens Axboe if (rw == READ) 262719c555fSJens Axboe bio->bi_end_io = bounce_end_io_read; 263ce288e05SChristoph Hellwig else 264ce288e05SChristoph Hellwig bio->bi_end_io = bounce_end_io_write; 265719c555fSJens Axboe 266719c555fSJens Axboe bio->bi_private = *bio_orig; 267719c555fSJens Axboe *bio_orig = bio; 268719c555fSJens Axboe } 269