cregit-Linux how code gets into the kernel

Release 4.18 block/bounce.c

Directory: block
// SPDX-License-Identifier: GPL-2.0
/* bounce buffer handling for block devices
 *
 * - Split from highmem.c
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/mm.h>
#include <linux/export.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/backing-dev.h>
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/highmem.h>
#include <linux/bootmem.h>
#include <linux/printk.h>
#include <asm/tlbflush.h>

#include <trace/events/block.h>
#include "blk.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, isa_page_pool;

#if defined(CONFIG_HIGHMEM)

static __init int init_emergency_pool(void) { int ret; #if defined(CONFIG_HIGHMEM) && !defined(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); 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); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Neil Brown4034.78%114.29%
David Howells3429.57%114.29%
Kent Overstreet2118.26%114.29%
Chris Metcalf119.57%114.29%
David Vrabel65.22%114.29%
Mitchel Humpherys21.74%114.29%
Jens Axboe10.87%114.29%
Total115100.00%7100.00%

__initcall(init_emergency_pool); #endif #ifdef CONFIG_HIGHMEM /* * highmem version, map in to vec */
static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom) { unsigned char *vto; vto = kmap_atomic(to->bv_page); memcpy(vto + to->bv_offset, vfrom, to->bv_len); kunmap_atomic(vto); }

Contributors

PersonTokensPropCommitsCommitProp
David Howells50100.00%1100.00%
Total50100.00%1100.00%

#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); }

Contributors

PersonTokensPropCommitsCommitProp
David Howells24100.00%1100.00%
Total24100.00%1100.00%

/* * 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) { int ret; if (mempool_initialized(&isa_page_pool)) return 0; ret = mempool_init(&isa_page_pool, ISA_POOL_SIZE, mempool_alloc_pages_isa, mempool_free_pages, (void *) 0); BUG_ON(ret); pr_info("isa pool size: %d pages\n", ISA_POOL_SIZE); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
David Howells4173.21%133.33%
Kent Overstreet1323.21%133.33%
Mitchel Humpherys23.57%133.33%
Total56100.00%3100.00%

/* * 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; 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 */ vfrom = page_address(fromvec.bv_page) + tovec.bv_offset; bounce_copy_vec(&tovec, vfrom); flush_dcache_page(tovec.bv_page); } bio_advance_iter(from, &from_iter, tovec.bv_len); } }

Contributors

PersonTokensPropCommitsCommitProp
David Howells6256.36%120.00%
Ming Lei2926.36%120.00%
Kent Overstreet1412.73%240.00%
Gary King54.55%120.00%
Total110100.00%5100.00%


static void bounce_end_io(struct bio *bio, mempool_t *pool) { struct bio *bio_orig = bio->bi_private; struct bio_vec *bvec, orig_vec; int i; struct bvec_iter orig_iter = bio_orig->bi_iter; /* * free up bounce indirect pages used */ bio_for_each_segment_all(bvec, bio, i) { 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, 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); }

Contributors

PersonTokensPropCommitsCommitProp
David Howells8166.39%116.67%
Ming Lei3226.23%233.33%
Christoph Hellwig86.56%233.33%
Kent Overstreet10.82%116.67%
Total122100.00%6100.00%


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

Contributors

PersonTokensPropCommitsCommitProp
David Howells1789.47%133.33%
Kent Overstreet15.26%133.33%
Neil Brown15.26%133.33%
Total19100.00%3100.00%


static void bounce_end_io_write_isa(struct bio *bio) { bounce_end_io(bio, &isa_page_pool); }

Contributors

PersonTokensPropCommitsCommitProp
David Howells1789.47%133.33%
Neil Brown15.26%133.33%
Kent Overstreet15.26%133.33%
Total19100.00%3100.00%


static void __bounce_end_io_read(struct bio *bio, mempool_t *pool) { struct bio *bio_orig = bio->bi_private; if (!bio->bi_status) copy_to_high_bio_irq(bio_orig, bio); bounce_end_io(bio, pool); }

Contributors

PersonTokensPropCommitsCommitProp
David Howells4395.56%133.33%
Christoph Hellwig24.44%266.67%
Total45100.00%3100.00%


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

Contributors

PersonTokensPropCommitsCommitProp
David Howells1789.47%133.33%
Kent Overstreet15.26%133.33%
Neil Brown15.26%133.33%
Total19100.00%3100.00%


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

Contributors

PersonTokensPropCommitsCommitProp
David Howells1789.47%133.33%
Kent Overstreet15.26%133.33%
Neil Brown15.26%133.33%
Total19100.00%3100.00%


static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, mempool_t *pool) { struct bio *bio; int rw = bio_data_dir(*bio_orig); struct bio_vec *to, from; struct bvec_iter iter; unsigned i = 0; bool bounce = false; int sectors = 0; bool passthrough = bio_is_passthrough(*bio_orig); bio_for_each_segment(from, *bio_orig, iter) { if (i++ < BIO_MAX_PAGES) sectors += from.bv_len >> 9; if (page_to_pfn(from.bv_page) > q->limits.bounce_pfn) bounce = true; } if (!bounce) return; if (!passthrough && sectors < bio_sectors(*bio_orig)) { bio = bio_split(*bio_orig, sectors, GFP_NOIO, &bounce_bio_split); bio_chain(bio, *bio_orig); generic_make_request(*bio_orig); *bio_orig = bio; } bio = bio_clone_bioset(*bio_orig, GFP_NOIO, passthrough ? NULL : &bounce_bio_set); bio_for_each_segment_all(to, bio, i) { struct page *page = to->bv_page; if (page_to_pfn(page) <= q->limits.bounce_pfn) continue; to->bv_page = mempool_alloc(pool, q->bounce_gfp); inc_zone_page_state(to->bv_page, NR_BOUNCE); if (rw == WRITE) { char *vto, *vfrom; flush_dcache_page(page); vto = page_address(to->bv_page) + to->bv_offset; vfrom = kmap_atomic(page) + to->bv_offset; memcpy(vto, vfrom, to->bv_len); kunmap_atomic(vfrom); } } trace_block_bio_bounce(q, *bio_orig); bio->bi_flags |= (1 << BIO_BOUNCED); 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; }

Contributors

PersonTokensPropCommitsCommitProp
David Howells19651.72%17.69%
Neil Brown8321.90%17.69%
Kent Overstreet5013.19%430.77%
Ming Lei164.22%17.69%
Jens Axboe164.22%323.08%
Wang YanQing92.37%17.69%
Christoph Hellwig82.11%17.69%
Arnaldo Carvalho de Melo10.26%17.69%
Total379100.00%13100.00%


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 (q->limits.bounce_pfn >= blk_max_pfn) return; pool = &page_pool; } else { BUG_ON(!mempool_initialized(&isa_page_pool)); pool = &isa_page_pool; } /* * slow path */ __blk_queue_bounce(q, bio_orig, pool); }

Contributors

PersonTokensPropCommitsCommitProp
David Howells6674.16%116.67%
Jens Axboe1314.61%350.00%
Kent Overstreet66.74%116.67%
Christoph Hellwig44.49%116.67%
Total89100.00%6100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
David Howells73762.30%12.94%
Neil Brown13311.24%25.88%
Kent Overstreet1099.21%514.71%
Ming Lei776.51%411.76%
Jens Axboe302.54%617.65%
Christoph Hellwig252.11%411.76%
Chris Metcalf211.78%12.94%
Mitchel Humpherys141.18%12.94%
Wang YanQing90.76%12.94%
David Vrabel90.76%12.94%
Tejun Heo60.51%25.88%
Gary King50.42%12.94%
Arnaldo Carvalho de Melo30.25%12.94%
Li Zefan20.17%12.94%
Greg Kroah-Hartman10.08%12.94%
Bart Van Assche10.08%12.94%
Paul Gortmaker10.08%12.94%
Jan Kara0.00%00.00%
Total1183100.00%34100.00%
Directory: block
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