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> 17e41d12f5SChristoph Hellwig #include <linux/blk-cgroup.h> 1866114cadSTejun Heo #include <linux/backing-dev.h> 19719c555fSJens Axboe #include <linux/init.h> 20719c555fSJens Axboe #include <linux/hash.h> 21719c555fSJens Axboe #include <linux/highmem.h> 22b1de0d13SMitchel Humpherys #include <linux/printk.h> 23719c555fSJens Axboe #include <asm/tlbflush.h> 24719c555fSJens Axboe 25719c555fSJens Axboe #include <trace/events/block.h> 263bce016aSChristoph Hellwig #include "blk.h" 27719c555fSJens Axboe 28719c555fSJens Axboe #define POOL_SIZE 64 29719c555fSJens Axboe #define ISA_POOL_SIZE 16 30719c555fSJens Axboe 31338aa96dSKent Overstreet static struct bio_set bounce_bio_set, bounce_bio_split; 32ce288e05SChristoph Hellwig static mempool_t page_pool; 33719c555fSJens Axboe 3452990a5fSJens Axboe static void init_bounce_bioset(void) 3552990a5fSJens Axboe { 3652990a5fSJens Axboe static bool bounce_bs_setup; 3752990a5fSJens Axboe int ret; 3852990a5fSJens Axboe 3952990a5fSJens Axboe if (bounce_bs_setup) 4052990a5fSJens Axboe return; 4152990a5fSJens Axboe 4252990a5fSJens Axboe ret = bioset_init(&bounce_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS); 4352990a5fSJens Axboe BUG_ON(ret); 4452990a5fSJens Axboe if (bioset_integrity_create(&bounce_bio_set, BIO_POOL_SIZE)) 4552990a5fSJens Axboe BUG_ON(1); 4652990a5fSJens Axboe 4752990a5fSJens Axboe ret = bioset_init(&bounce_bio_split, BIO_POOL_SIZE, 0, 0); 4852990a5fSJens Axboe BUG_ON(ret); 4952990a5fSJens Axboe bounce_bs_setup = true; 5052990a5fSJens Axboe } 5152990a5fSJens Axboe 52719c555fSJens Axboe static __init int init_emergency_pool(void) 53719c555fSJens Axboe { 54338aa96dSKent Overstreet int ret; 559bb33f24SChristoph Hellwig 569bb33f24SChristoph Hellwig #ifndef CONFIG_MEMORY_HOTPLUG 57719c555fSJens Axboe if (max_pfn <= max_low_pfn) 58719c555fSJens Axboe return 0; 59719c555fSJens Axboe #endif 60719c555fSJens Axboe 61338aa96dSKent Overstreet ret = mempool_init_page_pool(&page_pool, POOL_SIZE, 0); 62338aa96dSKent Overstreet BUG_ON(ret); 63b1de0d13SMitchel Humpherys pr_info("pool size: %d pages\n", POOL_SIZE); 64719c555fSJens Axboe 6552990a5fSJens Axboe init_bounce_bioset(); 66719c555fSJens Axboe return 0; 67719c555fSJens Axboe } 68719c555fSJens Axboe 69719c555fSJens Axboe __initcall(init_emergency_pool); 70719c555fSJens Axboe 71719c555fSJens Axboe /* 72719c555fSJens Axboe * Simple bounce buffer support for highmem pages. Depending on the 73719c555fSJens Axboe * queue gfp mask set, *to may or may not be a highmem page. kmap it 74719c555fSJens Axboe * always, it will do the Right Thing 75719c555fSJens Axboe */ 76719c555fSJens Axboe static void copy_to_high_bio_irq(struct bio *to, struct bio *from) 77719c555fSJens Axboe { 783c892a09SMing Lei struct bio_vec tovec, fromvec; 79719c555fSJens Axboe struct bvec_iter iter; 803c892a09SMing Lei /* 813c892a09SMing Lei * The bio of @from is created by bounce, so we can iterate 823c892a09SMing Lei * its bvec from start to end, but the @from->bi_iter can't be 833c892a09SMing Lei * trusted because it might be changed by splitting. 843c892a09SMing Lei */ 853c892a09SMing Lei struct bvec_iter from_iter = BVEC_ITER_ALL_INIT; 86719c555fSJens Axboe 87719c555fSJens Axboe bio_for_each_segment(tovec, to, iter) { 883c892a09SMing Lei fromvec = bio_iter_iovec(from, from_iter); 893c892a09SMing Lei if (tovec.bv_page != fromvec.bv_page) { 90719c555fSJens Axboe /* 91719c555fSJens Axboe * fromvec->bv_offset and fromvec->bv_len might have 92719c555fSJens Axboe * been modified by the block layer, so use the original 93719c555fSJens Axboe * copy, bounce_copy_vec already uses tovec->bv_len 94719c555fSJens Axboe */ 95f434cdc7SChristoph Hellwig memcpy_to_bvec(&tovec, page_address(fromvec.bv_page) + 96f434cdc7SChristoph Hellwig tovec.bv_offset); 97719c555fSJens Axboe } 983c892a09SMing Lei bio_advance_iter(from, &from_iter, tovec.bv_len); 99719c555fSJens Axboe } 100719c555fSJens Axboe } 101719c555fSJens Axboe 102ce288e05SChristoph Hellwig static void bounce_end_io(struct bio *bio) 103719c555fSJens Axboe { 104719c555fSJens Axboe struct bio *bio_orig = bio->bi_private; 1057891f05cSMing Lei struct bio_vec *bvec, orig_vec; 1067891f05cSMing Lei struct bvec_iter orig_iter = bio_orig->bi_iter; 1076dc4f100SMing Lei struct bvec_iter_all iter_all; 108719c555fSJens Axboe 109719c555fSJens Axboe /* 110719c555fSJens Axboe * free up bounce indirect pages used 111719c555fSJens Axboe */ 1122b070cfeSChristoph Hellwig bio_for_each_segment_all(bvec, bio, iter_all) { 1137891f05cSMing Lei orig_vec = bio_iter_iovec(bio_orig, orig_iter); 1147891f05cSMing Lei if (bvec->bv_page != orig_vec.bv_page) { 115719c555fSJens Axboe dec_zone_page_state(bvec->bv_page, NR_BOUNCE); 116ce288e05SChristoph Hellwig mempool_free(bvec->bv_page, &page_pool); 117719c555fSJens Axboe } 1187891f05cSMing Lei bio_advance_iter(bio_orig, &orig_iter, orig_vec.bv_len); 1197891f05cSMing Lei } 120719c555fSJens Axboe 1214e4cbee9SChristoph Hellwig bio_orig->bi_status = bio->bi_status; 1224246a0b6SChristoph Hellwig bio_endio(bio_orig); 123719c555fSJens Axboe bio_put(bio); 124719c555fSJens Axboe } 125719c555fSJens Axboe 1264246a0b6SChristoph Hellwig static void bounce_end_io_write(struct bio *bio) 127719c555fSJens Axboe { 128ce288e05SChristoph Hellwig bounce_end_io(bio); 129719c555fSJens Axboe } 130719c555fSJens Axboe 131ce288e05SChristoph Hellwig static void bounce_end_io_read(struct bio *bio) 132719c555fSJens Axboe { 133719c555fSJens Axboe struct bio *bio_orig = bio->bi_private; 134719c555fSJens Axboe 1354e4cbee9SChristoph Hellwig if (!bio->bi_status) 136719c555fSJens Axboe copy_to_high_bio_irq(bio_orig, bio); 137719c555fSJens Axboe 138ce288e05SChristoph Hellwig bounce_end_io(bio); 139719c555fSJens Axboe } 140719c555fSJens Axboe 141ebfe4183SChristoph Hellwig static struct bio *bounce_clone_bio(struct bio *bio_src) 142c55183c9SChristoph Hellwig { 143c55183c9SChristoph Hellwig struct bvec_iter iter; 144c55183c9SChristoph Hellwig struct bio_vec bv; 145c55183c9SChristoph Hellwig struct bio *bio; 146c55183c9SChristoph Hellwig 147c55183c9SChristoph Hellwig /* 148c55183c9SChristoph Hellwig * Pre immutable biovecs, __bio_clone() used to just do a memcpy from 149c55183c9SChristoph Hellwig * bio_src->bi_io_vec to bio->bi_io_vec. 150c55183c9SChristoph Hellwig * 151c55183c9SChristoph Hellwig * We can't do that anymore, because: 152c55183c9SChristoph Hellwig * 153c55183c9SChristoph Hellwig * - The point of cloning the biovec is to produce a bio with a biovec 154c55183c9SChristoph Hellwig * the caller can modify: bi_idx and bi_bvec_done should be 0. 155c55183c9SChristoph Hellwig * 156a8affc03SChristoph Hellwig * - The original bio could've had more than BIO_MAX_VECS biovecs; if 157c55183c9SChristoph Hellwig * we tried to clone the whole thing bio_alloc_bioset() would fail. 158c55183c9SChristoph Hellwig * But the clone should succeed as long as the number of biovecs we 159a8affc03SChristoph Hellwig * actually need to allocate is fewer than BIO_MAX_VECS. 160c55183c9SChristoph Hellwig * 161c55183c9SChristoph Hellwig * - Lastly, bi_vcnt should not be looked at or relied upon by code 162c55183c9SChristoph Hellwig * that does not own the bio - reason being drivers don't use it for 163c55183c9SChristoph Hellwig * iterating over the biovec anymore, so expecting it to be kept up 164c55183c9SChristoph Hellwig * to date (i.e. for clones that share the parent biovec) is just 165c55183c9SChristoph Hellwig * asking for trouble and would force extra work on 166c55183c9SChristoph Hellwig * __bio_clone_fast() anyways. 167c55183c9SChristoph Hellwig */ 168*609be106SChristoph Hellwig bio = bio_alloc_bioset(bio_src->bi_bdev, bio_segments(bio_src), 169*609be106SChristoph Hellwig bio_src->bi_opf, GFP_NOIO, &bounce_bio_set); 17046bbf653SChristoph Hellwig if (bio_flagged(bio_src, BIO_REMAPPED)) 17146bbf653SChristoph Hellwig bio_set_flag(bio, BIO_REMAPPED); 172ca474b73SHannes Reinecke bio->bi_ioprio = bio_src->bi_ioprio; 173c55183c9SChristoph Hellwig bio->bi_write_hint = bio_src->bi_write_hint; 174c55183c9SChristoph Hellwig bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector; 175c55183c9SChristoph Hellwig bio->bi_iter.bi_size = bio_src->bi_iter.bi_size; 176c55183c9SChristoph Hellwig 177c55183c9SChristoph Hellwig switch (bio_op(bio)) { 178c55183c9SChristoph Hellwig case REQ_OP_DISCARD: 179c55183c9SChristoph Hellwig case REQ_OP_SECURE_ERASE: 180c55183c9SChristoph Hellwig case REQ_OP_WRITE_ZEROES: 181c55183c9SChristoph Hellwig break; 182c55183c9SChristoph Hellwig case REQ_OP_WRITE_SAME: 183c55183c9SChristoph Hellwig bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0]; 184c55183c9SChristoph Hellwig break; 185c55183c9SChristoph Hellwig default: 186c55183c9SChristoph Hellwig bio_for_each_segment(bv, bio_src, iter) 187c55183c9SChristoph Hellwig bio->bi_io_vec[bio->bi_vcnt++] = bv; 188c55183c9SChristoph Hellwig break; 189c55183c9SChristoph Hellwig } 190c55183c9SChristoph Hellwig 191ebfe4183SChristoph Hellwig if (bio_crypt_clone(bio, bio_src, GFP_NOIO) < 0) 19207560151SEric Biggers goto err_put; 193a892c8d5SSatya Tangirala 19407560151SEric Biggers if (bio_integrity(bio_src) && 195ebfe4183SChristoph Hellwig bio_integrity_clone(bio, bio_src, GFP_NOIO) < 0) 19607560151SEric Biggers goto err_put; 197c55183c9SChristoph Hellwig 198db6638d7SDennis Zhou bio_clone_blkg_association(bio, bio_src); 199e439bedfSDennis Zhou blkcg_bio_issue_init(bio); 2005bf9a1f3SDennis Zhou (Facebook) 201c55183c9SChristoph Hellwig return bio; 20207560151SEric Biggers 20307560151SEric Biggers err_put: 20407560151SEric Biggers bio_put(bio); 20507560151SEric Biggers return NULL; 206c55183c9SChristoph Hellwig } 207c55183c9SChristoph Hellwig 2089bb33f24SChristoph Hellwig void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) 209719c555fSJens Axboe { 210719c555fSJens Axboe struct bio *bio; 211719c555fSJens Axboe int rw = bio_data_dir(*bio_orig); 212719c555fSJens Axboe struct bio_vec *to, from; 213719c555fSJens Axboe struct bvec_iter iter; 214a8821f3fSNeilBrown unsigned i = 0; 215a8821f3fSNeilBrown bool bounce = false; 216a8821f3fSNeilBrown int sectors = 0; 217719c555fSJens Axboe 218a8821f3fSNeilBrown bio_for_each_segment(from, *bio_orig, iter) { 219a8affc03SChristoph Hellwig if (i++ < BIO_MAX_VECS) 220a8821f3fSNeilBrown sectors += from.bv_len >> 9; 2219bb33f24SChristoph Hellwig if (PageHighMem(from.bv_page)) 222a8821f3fSNeilBrown bounce = true; 223a8821f3fSNeilBrown } 224a8821f3fSNeilBrown if (!bounce) 225719c555fSJens Axboe return; 226a8821f3fSNeilBrown 227393bb12eSChristoph Hellwig if (sectors < bio_sectors(*bio_orig)) { 228338aa96dSKent Overstreet bio = bio_split(*bio_orig, sectors, GFP_NOIO, &bounce_bio_split); 229a8821f3fSNeilBrown bio_chain(bio, *bio_orig); 230ed00aabdSChristoph Hellwig submit_bio_noacct(*bio_orig); 231a8821f3fSNeilBrown *bio_orig = bio; 232a8821f3fSNeilBrown } 233ebfe4183SChristoph Hellwig bio = bounce_clone_bio(*bio_orig); 234719c555fSJens Axboe 2358f4e80daSMing Lei /* 2368f4e80daSMing Lei * Bvec table can't be updated by bio_for_each_segment_all(), 2378f4e80daSMing Lei * so retrieve bvec from the table directly. This way is safe 2388f4e80daSMing Lei * because the 'bio' is single-page bvec. 2398f4e80daSMing Lei */ 2408f4e80daSMing Lei for (i = 0, to = bio->bi_io_vec; i < bio->bi_vcnt; to++, i++) { 2414aebe859SChristoph Hellwig struct page *bounce_page; 242719c555fSJens Axboe 2434aebe859SChristoph Hellwig if (!PageHighMem(to->bv_page)) 244719c555fSJens Axboe continue; 245719c555fSJens Axboe 2464aebe859SChristoph Hellwig bounce_page = mempool_alloc(&page_pool, GFP_NOIO); 2474aebe859SChristoph Hellwig inc_zone_page_state(bounce_page, NR_BOUNCE); 248719c555fSJens Axboe 249719c555fSJens Axboe if (rw == WRITE) { 2504aebe859SChristoph Hellwig flush_dcache_page(to->bv_page); 2514aebe859SChristoph Hellwig memcpy_from_bvec(page_address(bounce_page), to); 252719c555fSJens Axboe } 2534aebe859SChristoph Hellwig to->bv_page = bounce_page; 254719c555fSJens Axboe } 255719c555fSJens Axboe 256e8a676d6SChristoph Hellwig trace_block_bio_bounce(*bio_orig); 257719c555fSJens Axboe 258719c555fSJens Axboe bio->bi_flags |= (1 << BIO_BOUNCED); 259719c555fSJens Axboe 260719c555fSJens Axboe if (rw == READ) 261719c555fSJens Axboe bio->bi_end_io = bounce_end_io_read; 262ce288e05SChristoph Hellwig else 263ce288e05SChristoph Hellwig bio->bi_end_io = bounce_end_io_write; 264719c555fSJens Axboe 265719c555fSJens Axboe bio->bi_private = *bio_orig; 266719c555fSJens Axboe *bio_orig = bio; 267719c555fSJens Axboe } 268