From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- block/bounce.c | 268 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 268 insertions(+) create mode 100644 block/bounce.c (limited to 'block/bounce.c') diff --git a/block/bounce.c b/block/bounce.c new file mode 100644 index 000000000..7cfcb242f --- /dev/null +++ b/block/bounce.c @@ -0,0 +1,268 @@ +// SPDX-License-Identifier: GPL-2.0 +/* bounce buffer handling for block devices + * + * - Split from highmem.c + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include "blk.h" +#include "blk-cgroup.h" + +#define POOL_SIZE 64 +#define ISA_POOL_SIZE 16 + +static struct bio_set bounce_bio_set, bounce_bio_split; +static mempool_t page_pool; + +static void init_bounce_bioset(void) +{ + static bool bounce_bs_setup; + int ret; + + if (bounce_bs_setup) + return; + + ret = bioset_init(&bounce_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS); + BUG_ON(ret); + if (bioset_integrity_create(&bounce_bio_set, BIO_POOL_SIZE)) + BUG_ON(1); + + ret = bioset_init(&bounce_bio_split, BIO_POOL_SIZE, 0, 0); + BUG_ON(ret); + bounce_bs_setup = true; +} + +static __init int init_emergency_pool(void) +{ + int ret; + +#ifndef CONFIG_MEMORY_HOTPLUG + if (max_pfn <= max_low_pfn) + return 0; +#endif + + ret = mempool_init_page_pool(&page_pool, POOL_SIZE, 0); + BUG_ON(ret); + pr_info("pool size: %d pages\n", POOL_SIZE); + + init_bounce_bioset(); + return 0; +} + +__initcall(init_emergency_pool); + +/* + * 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) +{ + struct bio_vec tovec, fromvec; + struct bvec_iter iter; + /* + * The bio of @from is created by bounce, so we can iterate + * its bvec from start to end, but the @from->bi_iter can't be + * trusted because it might be changed by splitting. + */ + struct bvec_iter from_iter = BVEC_ITER_ALL_INIT; + + bio_for_each_segment(tovec, to, iter) { + fromvec = bio_iter_iovec(from, from_iter); + if (tovec.bv_page != fromvec.bv_page) { + /* + * 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 + */ + memcpy_to_bvec(&tovec, page_address(fromvec.bv_page) + + tovec.bv_offset); + } + bio_advance_iter(from, &from_iter, tovec.bv_len); + } +} + +static void bounce_end_io(struct bio *bio) +{ + struct bio *bio_orig = bio->bi_private; + struct bio_vec *bvec, orig_vec; + struct bvec_iter orig_iter = bio_orig->bi_iter; + struct bvec_iter_all iter_all; + + /* + * free up bounce indirect pages used + */ + bio_for_each_segment_all(bvec, bio, iter_all) { + orig_vec = bio_iter_iovec(bio_orig, orig_iter); + if (bvec->bv_page != orig_vec.bv_page) { + dec_zone_page_state(bvec->bv_page, NR_BOUNCE); + mempool_free(bvec->bv_page, &page_pool); + } + bio_advance_iter(bio_orig, &orig_iter, orig_vec.bv_len); + } + + bio_orig->bi_status = bio->bi_status; + bio_endio(bio_orig); + bio_put(bio); +} + +static void bounce_end_io_write(struct bio *bio) +{ + bounce_end_io(bio); +} + +static void bounce_end_io_read(struct bio *bio) +{ + struct bio *bio_orig = bio->bi_private; + + if (!bio->bi_status) + copy_to_high_bio_irq(bio_orig, bio); + + bounce_end_io(bio); +} + +static struct bio *bounce_clone_bio(struct bio *bio_src) +{ + struct bvec_iter iter; + struct bio_vec bv; + struct bio *bio; + + /* + * Pre immutable biovecs, __bio_clone() used to just do a memcpy from + * bio_src->bi_io_vec to bio->bi_io_vec. + * + * We can't do that anymore, because: + * + * - The point of cloning the biovec is to produce a bio with a biovec + * the caller can modify: bi_idx and bi_bvec_done should be 0. + * + * - The original bio could've had more than BIO_MAX_VECS biovecs; if + * we tried to clone the whole thing bio_alloc_bioset() would fail. + * But the clone should succeed as long as the number of biovecs we + * actually need to allocate is fewer than BIO_MAX_VECS. + * + * - Lastly, bi_vcnt should not be looked at or relied upon by code + * that does not own the bio - reason being drivers don't use it for + * iterating over the biovec anymore, so expecting it to be kept up + * to date (i.e. for clones that share the parent biovec) is just + * asking for trouble and would force extra work. + */ + bio = bio_alloc_bioset(bio_src->bi_bdev, bio_segments(bio_src), + bio_src->bi_opf, GFP_NOIO, &bounce_bio_set); + if (bio_flagged(bio_src, BIO_REMAPPED)) + bio_set_flag(bio, BIO_REMAPPED); + bio->bi_ioprio = bio_src->bi_ioprio; + bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector; + bio->bi_iter.bi_size = bio_src->bi_iter.bi_size; + + switch (bio_op(bio)) { + case REQ_OP_DISCARD: + case REQ_OP_SECURE_ERASE: + case REQ_OP_WRITE_ZEROES: + break; + default: + bio_for_each_segment(bv, bio_src, iter) + bio->bi_io_vec[bio->bi_vcnt++] = bv; + break; + } + + if (bio_crypt_clone(bio, bio_src, GFP_NOIO) < 0) + goto err_put; + + if (bio_integrity(bio_src) && + bio_integrity_clone(bio, bio_src, GFP_NOIO) < 0) + goto err_put; + + bio_clone_blkg_association(bio, bio_src); + + return bio; + +err_put: + bio_put(bio); + return NULL; +} + +struct bio *__blk_queue_bounce(struct bio *bio_orig, struct request_queue *q) +{ + struct bio *bio; + int rw = bio_data_dir(bio_orig); + struct bio_vec *to, from; + struct bvec_iter iter; + unsigned i = 0, bytes = 0; + bool bounce = false; + int sectors; + + bio_for_each_segment(from, bio_orig, iter) { + if (i++ < BIO_MAX_VECS) + bytes += from.bv_len; + if (PageHighMem(from.bv_page)) + bounce = true; + } + if (!bounce) + return bio_orig; + + /* + * Individual bvecs might not be logical block aligned. Round down + * the split size so that each bio is properly block size aligned, + * even if we do not use the full hardware limits. + */ + sectors = ALIGN_DOWN(bytes, queue_logical_block_size(q)) >> + SECTOR_SHIFT; + if (sectors < bio_sectors(bio_orig)) { + bio = bio_split(bio_orig, sectors, GFP_NOIO, &bounce_bio_split); + bio_chain(bio, bio_orig); + submit_bio_noacct(bio_orig); + bio_orig = bio; + } + bio = bounce_clone_bio(bio_orig); + + /* + * Bvec table can't be updated by bio_for_each_segment_all(), + * so retrieve bvec from the table directly. This way is safe + * because the 'bio' is single-page bvec. + */ + for (i = 0, to = bio->bi_io_vec; i < bio->bi_vcnt; to++, i++) { + struct page *bounce_page; + + if (!PageHighMem(to->bv_page)) + continue; + + bounce_page = mempool_alloc(&page_pool, GFP_NOIO); + inc_zone_page_state(bounce_page, NR_BOUNCE); + + if (rw == WRITE) { + flush_dcache_page(to->bv_page); + memcpy_from_bvec(page_address(bounce_page), to); + } + to->bv_page = bounce_page; + } + + trace_block_bio_bounce(bio_orig); + + bio->bi_flags |= (1 << BIO_BOUNCED); + + if (rw == READ) + bio->bi_end_io = bounce_end_io_read; + else + bio->bi_end_io = bounce_end_io_write; + + bio->bi_private = bio_orig; + return bio; +} -- cgit v1.2.3