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d81665198b
If we pass in an offset which is larger than PAGE_SIZE, then
page_is_mergeable() thinks it's not mergeable with the previous bio_vec,
leading to a large number of bio_vecs being used. Use a slightly more
obvious test that the two pages are compatible with each other.
Fixes: 52d52d1c98
("block: only allow contiguous page structs in a bio_vec")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1673 lines
44 KiB
C
1673 lines
44 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
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*/
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/uio.h>
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#include <linux/iocontext.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/mempool.h>
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#include <linux/workqueue.h>
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#include <linux/cgroup.h>
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#include <linux/blk-cgroup.h>
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#include <linux/highmem.h>
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#include <linux/sched/sysctl.h>
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#include <linux/blk-crypto.h>
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#include <trace/events/block.h>
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#include "blk.h"
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#include "blk-rq-qos.h"
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/*
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* Test patch to inline a certain number of bi_io_vec's inside the bio
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* itself, to shrink a bio data allocation from two mempool calls to one
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*/
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#define BIO_INLINE_VECS 4
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/*
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* if you change this list, also change bvec_alloc or things will
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* break badly! cannot be bigger than what you can fit into an
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* unsigned short
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*/
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#define BV(x, n) { .nr_vecs = x, .name = "biovec-"#n }
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static struct biovec_slab bvec_slabs[BVEC_POOL_NR] __read_mostly = {
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BV(1, 1), BV(4, 4), BV(16, 16), BV(64, 64), BV(128, 128), BV(BIO_MAX_PAGES, max),
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};
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#undef BV
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/*
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* fs_bio_set is the bio_set containing bio and iovec memory pools used by
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* IO code that does not need private memory pools.
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*/
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struct bio_set fs_bio_set;
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EXPORT_SYMBOL(fs_bio_set);
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/*
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* Our slab pool management
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*/
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struct bio_slab {
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struct kmem_cache *slab;
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unsigned int slab_ref;
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unsigned int slab_size;
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char name[8];
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};
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static DEFINE_MUTEX(bio_slab_lock);
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static struct bio_slab *bio_slabs;
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static unsigned int bio_slab_nr, bio_slab_max;
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static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
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{
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unsigned int sz = sizeof(struct bio) + extra_size;
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struct kmem_cache *slab = NULL;
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struct bio_slab *bslab, *new_bio_slabs;
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unsigned int new_bio_slab_max;
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unsigned int i, entry = -1;
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mutex_lock(&bio_slab_lock);
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i = 0;
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while (i < bio_slab_nr) {
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bslab = &bio_slabs[i];
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if (!bslab->slab && entry == -1)
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entry = i;
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else if (bslab->slab_size == sz) {
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slab = bslab->slab;
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bslab->slab_ref++;
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break;
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}
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i++;
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}
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if (slab)
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goto out_unlock;
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if (bio_slab_nr == bio_slab_max && entry == -1) {
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new_bio_slab_max = bio_slab_max << 1;
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new_bio_slabs = krealloc(bio_slabs,
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new_bio_slab_max * sizeof(struct bio_slab),
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GFP_KERNEL);
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if (!new_bio_slabs)
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goto out_unlock;
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bio_slab_max = new_bio_slab_max;
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bio_slabs = new_bio_slabs;
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}
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if (entry == -1)
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entry = bio_slab_nr++;
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bslab = &bio_slabs[entry];
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snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
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slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN,
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SLAB_HWCACHE_ALIGN, NULL);
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if (!slab)
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goto out_unlock;
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bslab->slab = slab;
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bslab->slab_ref = 1;
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bslab->slab_size = sz;
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out_unlock:
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mutex_unlock(&bio_slab_lock);
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return slab;
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}
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static void bio_put_slab(struct bio_set *bs)
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{
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struct bio_slab *bslab = NULL;
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unsigned int i;
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mutex_lock(&bio_slab_lock);
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for (i = 0; i < bio_slab_nr; i++) {
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if (bs->bio_slab == bio_slabs[i].slab) {
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bslab = &bio_slabs[i];
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break;
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}
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}
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if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
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goto out;
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WARN_ON(!bslab->slab_ref);
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if (--bslab->slab_ref)
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goto out;
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kmem_cache_destroy(bslab->slab);
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bslab->slab = NULL;
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out:
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mutex_unlock(&bio_slab_lock);
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}
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unsigned int bvec_nr_vecs(unsigned short idx)
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{
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return bvec_slabs[--idx].nr_vecs;
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}
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void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
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{
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if (!idx)
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return;
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idx--;
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BIO_BUG_ON(idx >= BVEC_POOL_NR);
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if (idx == BVEC_POOL_MAX) {
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mempool_free(bv, pool);
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} else {
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struct biovec_slab *bvs = bvec_slabs + idx;
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kmem_cache_free(bvs->slab, bv);
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}
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}
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struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
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mempool_t *pool)
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{
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struct bio_vec *bvl;
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/*
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* see comment near bvec_array define!
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*/
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switch (nr) {
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case 1:
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*idx = 0;
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break;
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case 2 ... 4:
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*idx = 1;
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break;
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case 5 ... 16:
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*idx = 2;
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break;
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case 17 ... 64:
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*idx = 3;
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break;
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case 65 ... 128:
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*idx = 4;
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break;
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case 129 ... BIO_MAX_PAGES:
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*idx = 5;
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break;
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default:
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return NULL;
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}
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/*
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* idx now points to the pool we want to allocate from. only the
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* 1-vec entry pool is mempool backed.
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*/
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if (*idx == BVEC_POOL_MAX) {
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fallback:
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bvl = mempool_alloc(pool, gfp_mask);
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} else {
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struct biovec_slab *bvs = bvec_slabs + *idx;
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gfp_t __gfp_mask = gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_IO);
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/*
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* Make this allocation restricted and don't dump info on
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* allocation failures, since we'll fallback to the mempool
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* in case of failure.
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*/
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__gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
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/*
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* Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM
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* is set, retry with the 1-entry mempool
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*/
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bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
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if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) {
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*idx = BVEC_POOL_MAX;
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goto fallback;
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}
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}
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(*idx)++;
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return bvl;
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}
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void bio_uninit(struct bio *bio)
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{
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#ifdef CONFIG_BLK_CGROUP
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if (bio->bi_blkg) {
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blkg_put(bio->bi_blkg);
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bio->bi_blkg = NULL;
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}
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#endif
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if (bio_integrity(bio))
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bio_integrity_free(bio);
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bio_crypt_free_ctx(bio);
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}
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EXPORT_SYMBOL(bio_uninit);
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static void bio_free(struct bio *bio)
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{
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struct bio_set *bs = bio->bi_pool;
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void *p;
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bio_uninit(bio);
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if (bs) {
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bvec_free(&bs->bvec_pool, bio->bi_io_vec, BVEC_POOL_IDX(bio));
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/*
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* If we have front padding, adjust the bio pointer before freeing
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*/
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p = bio;
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p -= bs->front_pad;
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mempool_free(p, &bs->bio_pool);
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} else {
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/* Bio was allocated by bio_kmalloc() */
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kfree(bio);
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}
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}
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/*
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* Users of this function have their own bio allocation. Subsequently,
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* they must remember to pair any call to bio_init() with bio_uninit()
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* when IO has completed, or when the bio is released.
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*/
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void bio_init(struct bio *bio, struct bio_vec *table,
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unsigned short max_vecs)
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{
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memset(bio, 0, sizeof(*bio));
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atomic_set(&bio->__bi_remaining, 1);
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atomic_set(&bio->__bi_cnt, 1);
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bio->bi_io_vec = table;
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bio->bi_max_vecs = max_vecs;
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}
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EXPORT_SYMBOL(bio_init);
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/**
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* bio_reset - reinitialize a bio
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* @bio: bio to reset
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*
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* Description:
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* After calling bio_reset(), @bio will be in the same state as a freshly
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* allocated bio returned bio bio_alloc_bioset() - the only fields that are
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* preserved are the ones that are initialized by bio_alloc_bioset(). See
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* comment in struct bio.
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*/
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void bio_reset(struct bio *bio)
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{
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unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
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bio_uninit(bio);
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memset(bio, 0, BIO_RESET_BYTES);
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bio->bi_flags = flags;
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atomic_set(&bio->__bi_remaining, 1);
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}
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EXPORT_SYMBOL(bio_reset);
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static struct bio *__bio_chain_endio(struct bio *bio)
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{
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struct bio *parent = bio->bi_private;
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if (!parent->bi_status)
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parent->bi_status = bio->bi_status;
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bio_put(bio);
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return parent;
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}
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static void bio_chain_endio(struct bio *bio)
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{
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bio_endio(__bio_chain_endio(bio));
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}
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/**
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* bio_chain - chain bio completions
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* @bio: the target bio
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* @parent: the @bio's parent bio
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*
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* The caller won't have a bi_end_io called when @bio completes - instead,
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* @parent's bi_end_io won't be called until both @parent and @bio have
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* completed; the chained bio will also be freed when it completes.
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*
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* The caller must not set bi_private or bi_end_io in @bio.
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*/
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void bio_chain(struct bio *bio, struct bio *parent)
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{
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BUG_ON(bio->bi_private || bio->bi_end_io);
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bio->bi_private = parent;
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bio->bi_end_io = bio_chain_endio;
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bio_inc_remaining(parent);
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}
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EXPORT_SYMBOL(bio_chain);
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static void bio_alloc_rescue(struct work_struct *work)
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{
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struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
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struct bio *bio;
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while (1) {
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spin_lock(&bs->rescue_lock);
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bio = bio_list_pop(&bs->rescue_list);
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spin_unlock(&bs->rescue_lock);
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if (!bio)
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break;
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submit_bio_noacct(bio);
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}
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}
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static void punt_bios_to_rescuer(struct bio_set *bs)
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{
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struct bio_list punt, nopunt;
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struct bio *bio;
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if (WARN_ON_ONCE(!bs->rescue_workqueue))
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return;
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/*
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* In order to guarantee forward progress we must punt only bios that
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* were allocated from this bio_set; otherwise, if there was a bio on
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* there for a stacking driver higher up in the stack, processing it
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* could require allocating bios from this bio_set, and doing that from
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* our own rescuer would be bad.
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*
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* Since bio lists are singly linked, pop them all instead of trying to
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* remove from the middle of the list:
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*/
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bio_list_init(&punt);
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bio_list_init(&nopunt);
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while ((bio = bio_list_pop(¤t->bio_list[0])))
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bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
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current->bio_list[0] = nopunt;
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bio_list_init(&nopunt);
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while ((bio = bio_list_pop(¤t->bio_list[1])))
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bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
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current->bio_list[1] = nopunt;
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spin_lock(&bs->rescue_lock);
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bio_list_merge(&bs->rescue_list, &punt);
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spin_unlock(&bs->rescue_lock);
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queue_work(bs->rescue_workqueue, &bs->rescue_work);
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}
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/**
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* bio_alloc_bioset - allocate a bio for I/O
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* @gfp_mask: the GFP_* mask given to the slab allocator
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* @nr_iovecs: number of iovecs to pre-allocate
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* @bs: the bio_set to allocate from.
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*
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* Description:
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* If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
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* backed by the @bs's mempool.
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*
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* When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will
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* always be able to allocate a bio. This is due to the mempool guarantees.
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* To make this work, callers must never allocate more than 1 bio at a time
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* from this pool. Callers that need to allocate more than 1 bio must always
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* submit the previously allocated bio for IO before attempting to allocate
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* a new one. Failure to do so can cause deadlocks under memory pressure.
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*
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* Note that when running under submit_bio_noacct() (i.e. any block
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* driver), bios are not submitted until after you return - see the code in
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* submit_bio_noacct() that converts recursion into iteration, to prevent
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* stack overflows.
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*
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* This would normally mean allocating multiple bios under
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* submit_bio_noacct() would be susceptible to deadlocks, but we have
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* deadlock avoidance code that resubmits any blocked bios from a rescuer
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* thread.
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*
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* However, we do not guarantee forward progress for allocations from other
|
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* mempools. Doing multiple allocations from the same mempool under
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* submit_bio_noacct() should be avoided - instead, use bio_set's front_pad
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* for per bio allocations.
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*
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* RETURNS:
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* Pointer to new bio on success, NULL on failure.
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*/
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struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned int nr_iovecs,
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struct bio_set *bs)
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{
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gfp_t saved_gfp = gfp_mask;
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unsigned front_pad;
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unsigned inline_vecs;
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struct bio_vec *bvl = NULL;
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struct bio *bio;
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void *p;
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|
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if (!bs) {
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if (nr_iovecs > UIO_MAXIOV)
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return NULL;
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|
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p = kmalloc(struct_size(bio, bi_inline_vecs, nr_iovecs), gfp_mask);
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front_pad = 0;
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inline_vecs = nr_iovecs;
|
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} else {
|
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/* should not use nobvec bioset for nr_iovecs > 0 */
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if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) &&
|
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nr_iovecs > 0))
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return NULL;
|
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/*
|
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* submit_bio_noacct() converts recursion to iteration; this
|
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* means if we're running beneath it, any bios we allocate and
|
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* submit will not be submitted (and thus freed) until after we
|
|
* return.
|
|
*
|
|
* This exposes us to a potential deadlock if we allocate
|
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* multiple bios from the same bio_set() while running
|
|
* underneath submit_bio_noacct(). If we were to allocate
|
|
* multiple bios (say a stacking block driver that was splitting
|
|
* bios), we would deadlock if we exhausted the mempool's
|
|
* reserve.
|
|
*
|
|
* We solve this, and guarantee forward progress, with a rescuer
|
|
* workqueue per bio_set. If we go to allocate and there are
|
|
* bios on current->bio_list, we first try the allocation
|
|
* without __GFP_DIRECT_RECLAIM; if that fails, we punt those
|
|
* bios we would be blocking to the rescuer workqueue before
|
|
* we retry with the original gfp_flags.
|
|
*/
|
|
|
|
if (current->bio_list &&
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(!bio_list_empty(¤t->bio_list[0]) ||
|
|
!bio_list_empty(¤t->bio_list[1])) &&
|
|
bs->rescue_workqueue)
|
|
gfp_mask &= ~__GFP_DIRECT_RECLAIM;
|
|
|
|
p = mempool_alloc(&bs->bio_pool, gfp_mask);
|
|
if (!p && gfp_mask != saved_gfp) {
|
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punt_bios_to_rescuer(bs);
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|
gfp_mask = saved_gfp;
|
|
p = mempool_alloc(&bs->bio_pool, gfp_mask);
|
|
}
|
|
|
|
front_pad = bs->front_pad;
|
|
inline_vecs = BIO_INLINE_VECS;
|
|
}
|
|
|
|
if (unlikely(!p))
|
|
return NULL;
|
|
|
|
bio = p + front_pad;
|
|
bio_init(bio, NULL, 0);
|
|
|
|
if (nr_iovecs > inline_vecs) {
|
|
unsigned long idx = 0;
|
|
|
|
bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, &bs->bvec_pool);
|
|
if (!bvl && gfp_mask != saved_gfp) {
|
|
punt_bios_to_rescuer(bs);
|
|
gfp_mask = saved_gfp;
|
|
bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, &bs->bvec_pool);
|
|
}
|
|
|
|
if (unlikely(!bvl))
|
|
goto err_free;
|
|
|
|
bio->bi_flags |= idx << BVEC_POOL_OFFSET;
|
|
} else if (nr_iovecs) {
|
|
bvl = bio->bi_inline_vecs;
|
|
}
|
|
|
|
bio->bi_pool = bs;
|
|
bio->bi_max_vecs = nr_iovecs;
|
|
bio->bi_io_vec = bvl;
|
|
return bio;
|
|
|
|
err_free:
|
|
mempool_free(p, &bs->bio_pool);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(bio_alloc_bioset);
|
|
|
|
void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start)
|
|
{
|
|
unsigned long flags;
|
|
struct bio_vec bv;
|
|
struct bvec_iter iter;
|
|
|
|
__bio_for_each_segment(bv, bio, iter, start) {
|
|
char *data = bvec_kmap_irq(&bv, &flags);
|
|
memset(data, 0, bv.bv_len);
|
|
flush_dcache_page(bv.bv_page);
|
|
bvec_kunmap_irq(data, &flags);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(zero_fill_bio_iter);
|
|
|
|
/**
|
|
* bio_truncate - truncate the bio to small size of @new_size
|
|
* @bio: the bio to be truncated
|
|
* @new_size: new size for truncating the bio
|
|
*
|
|
* Description:
|
|
* Truncate the bio to new size of @new_size. If bio_op(bio) is
|
|
* REQ_OP_READ, zero the truncated part. This function should only
|
|
* be used for handling corner cases, such as bio eod.
|
|
*/
|
|
void bio_truncate(struct bio *bio, unsigned new_size)
|
|
{
|
|
struct bio_vec bv;
|
|
struct bvec_iter iter;
|
|
unsigned int done = 0;
|
|
bool truncated = false;
|
|
|
|
if (new_size >= bio->bi_iter.bi_size)
|
|
return;
|
|
|
|
if (bio_op(bio) != REQ_OP_READ)
|
|
goto exit;
|
|
|
|
bio_for_each_segment(bv, bio, iter) {
|
|
if (done + bv.bv_len > new_size) {
|
|
unsigned offset;
|
|
|
|
if (!truncated)
|
|
offset = new_size - done;
|
|
else
|
|
offset = 0;
|
|
zero_user(bv.bv_page, offset, bv.bv_len - offset);
|
|
truncated = true;
|
|
}
|
|
done += bv.bv_len;
|
|
}
|
|
|
|
exit:
|
|
/*
|
|
* Don't touch bvec table here and make it really immutable, since
|
|
* fs bio user has to retrieve all pages via bio_for_each_segment_all
|
|
* in its .end_bio() callback.
|
|
*
|
|
* It is enough to truncate bio by updating .bi_size since we can make
|
|
* correct bvec with the updated .bi_size for drivers.
|
|
*/
|
|
bio->bi_iter.bi_size = new_size;
|
|
}
|
|
|
|
/**
|
|
* guard_bio_eod - truncate a BIO to fit the block device
|
|
* @bio: bio to truncate
|
|
*
|
|
* This allows us to do IO even on the odd last sectors of a device, even if the
|
|
* block size is some multiple of the physical sector size.
|
|
*
|
|
* We'll just truncate the bio to the size of the device, and clear the end of
|
|
* the buffer head manually. Truly out-of-range accesses will turn into actual
|
|
* I/O errors, this only handles the "we need to be able to do I/O at the final
|
|
* sector" case.
|
|
*/
|
|
void guard_bio_eod(struct bio *bio)
|
|
{
|
|
sector_t maxsector;
|
|
struct hd_struct *part;
|
|
|
|
rcu_read_lock();
|
|
part = __disk_get_part(bio->bi_disk, bio->bi_partno);
|
|
if (part)
|
|
maxsector = part_nr_sects_read(part);
|
|
else
|
|
maxsector = get_capacity(bio->bi_disk);
|
|
rcu_read_unlock();
|
|
|
|
if (!maxsector)
|
|
return;
|
|
|
|
/*
|
|
* If the *whole* IO is past the end of the device,
|
|
* let it through, and the IO layer will turn it into
|
|
* an EIO.
|
|
*/
|
|
if (unlikely(bio->bi_iter.bi_sector >= maxsector))
|
|
return;
|
|
|
|
maxsector -= bio->bi_iter.bi_sector;
|
|
if (likely((bio->bi_iter.bi_size >> 9) <= maxsector))
|
|
return;
|
|
|
|
bio_truncate(bio, maxsector << 9);
|
|
}
|
|
|
|
/**
|
|
* bio_put - release a reference to a bio
|
|
* @bio: bio to release reference to
|
|
*
|
|
* Description:
|
|
* Put a reference to a &struct bio, either one you have gotten with
|
|
* bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it.
|
|
**/
|
|
void bio_put(struct bio *bio)
|
|
{
|
|
if (!bio_flagged(bio, BIO_REFFED))
|
|
bio_free(bio);
|
|
else {
|
|
BIO_BUG_ON(!atomic_read(&bio->__bi_cnt));
|
|
|
|
/*
|
|
* last put frees it
|
|
*/
|
|
if (atomic_dec_and_test(&bio->__bi_cnt))
|
|
bio_free(bio);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(bio_put);
|
|
|
|
/**
|
|
* __bio_clone_fast - clone a bio that shares the original bio's biovec
|
|
* @bio: destination bio
|
|
* @bio_src: bio to clone
|
|
*
|
|
* Clone a &bio. Caller will own the returned bio, but not
|
|
* the actual data it points to. Reference count of returned
|
|
* bio will be one.
|
|
*
|
|
* Caller must ensure that @bio_src is not freed before @bio.
|
|
*/
|
|
void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
|
|
{
|
|
BUG_ON(bio->bi_pool && BVEC_POOL_IDX(bio));
|
|
|
|
/*
|
|
* most users will be overriding ->bi_disk with a new target,
|
|
* so we don't set nor calculate new physical/hw segment counts here
|
|
*/
|
|
bio->bi_disk = bio_src->bi_disk;
|
|
bio->bi_partno = bio_src->bi_partno;
|
|
bio_set_flag(bio, BIO_CLONED);
|
|
if (bio_flagged(bio_src, BIO_THROTTLED))
|
|
bio_set_flag(bio, BIO_THROTTLED);
|
|
bio->bi_opf = bio_src->bi_opf;
|
|
bio->bi_ioprio = bio_src->bi_ioprio;
|
|
bio->bi_write_hint = bio_src->bi_write_hint;
|
|
bio->bi_iter = bio_src->bi_iter;
|
|
bio->bi_io_vec = bio_src->bi_io_vec;
|
|
|
|
bio_clone_blkg_association(bio, bio_src);
|
|
blkcg_bio_issue_init(bio);
|
|
}
|
|
EXPORT_SYMBOL(__bio_clone_fast);
|
|
|
|
/**
|
|
* bio_clone_fast - clone a bio that shares the original bio's biovec
|
|
* @bio: bio to clone
|
|
* @gfp_mask: allocation priority
|
|
* @bs: bio_set to allocate from
|
|
*
|
|
* Like __bio_clone_fast, only also allocates the returned bio
|
|
*/
|
|
struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
|
|
{
|
|
struct bio *b;
|
|
|
|
b = bio_alloc_bioset(gfp_mask, 0, bs);
|
|
if (!b)
|
|
return NULL;
|
|
|
|
__bio_clone_fast(b, bio);
|
|
|
|
bio_crypt_clone(b, bio, gfp_mask);
|
|
|
|
if (bio_integrity(bio)) {
|
|
int ret;
|
|
|
|
ret = bio_integrity_clone(b, bio, gfp_mask);
|
|
|
|
if (ret < 0) {
|
|
bio_put(b);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
return b;
|
|
}
|
|
EXPORT_SYMBOL(bio_clone_fast);
|
|
|
|
const char *bio_devname(struct bio *bio, char *buf)
|
|
{
|
|
return disk_name(bio->bi_disk, bio->bi_partno, buf);
|
|
}
|
|
EXPORT_SYMBOL(bio_devname);
|
|
|
|
static inline bool page_is_mergeable(const struct bio_vec *bv,
|
|
struct page *page, unsigned int len, unsigned int off,
|
|
bool *same_page)
|
|
{
|
|
size_t bv_end = bv->bv_offset + bv->bv_len;
|
|
phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1;
|
|
phys_addr_t page_addr = page_to_phys(page);
|
|
|
|
if (vec_end_addr + 1 != page_addr + off)
|
|
return false;
|
|
if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))
|
|
return false;
|
|
|
|
*same_page = ((vec_end_addr & PAGE_MASK) == page_addr);
|
|
if (*same_page)
|
|
return true;
|
|
return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE);
|
|
}
|
|
|
|
/*
|
|
* Try to merge a page into a segment, while obeying the hardware segment
|
|
* size limit. This is not for normal read/write bios, but for passthrough
|
|
* or Zone Append operations that we can't split.
|
|
*/
|
|
static bool bio_try_merge_hw_seg(struct request_queue *q, struct bio *bio,
|
|
struct page *page, unsigned len,
|
|
unsigned offset, bool *same_page)
|
|
{
|
|
struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
|
|
unsigned long mask = queue_segment_boundary(q);
|
|
phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset;
|
|
phys_addr_t addr2 = page_to_phys(page) + offset + len - 1;
|
|
|
|
if ((addr1 | mask) != (addr2 | mask))
|
|
return false;
|
|
if (bv->bv_len + len > queue_max_segment_size(q))
|
|
return false;
|
|
return __bio_try_merge_page(bio, page, len, offset, same_page);
|
|
}
|
|
|
|
/**
|
|
* bio_add_hw_page - attempt to add a page to a bio with hw constraints
|
|
* @q: the target queue
|
|
* @bio: destination bio
|
|
* @page: page to add
|
|
* @len: vec entry length
|
|
* @offset: vec entry offset
|
|
* @max_sectors: maximum number of sectors that can be added
|
|
* @same_page: return if the segment has been merged inside the same page
|
|
*
|
|
* Add a page to a bio while respecting the hardware max_sectors, max_segment
|
|
* and gap limitations.
|
|
*/
|
|
int bio_add_hw_page(struct request_queue *q, struct bio *bio,
|
|
struct page *page, unsigned int len, unsigned int offset,
|
|
unsigned int max_sectors, bool *same_page)
|
|
{
|
|
struct bio_vec *bvec;
|
|
|
|
if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
|
|
return 0;
|
|
|
|
if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
|
|
return 0;
|
|
|
|
if (bio->bi_vcnt > 0) {
|
|
if (bio_try_merge_hw_seg(q, bio, page, len, offset, same_page))
|
|
return len;
|
|
|
|
/*
|
|
* If the queue doesn't support SG gaps and adding this segment
|
|
* would create a gap, disallow it.
|
|
*/
|
|
bvec = &bio->bi_io_vec[bio->bi_vcnt - 1];
|
|
if (bvec_gap_to_prev(q, bvec, offset))
|
|
return 0;
|
|
}
|
|
|
|
if (bio_full(bio, len))
|
|
return 0;
|
|
|
|
if (bio->bi_vcnt >= queue_max_segments(q))
|
|
return 0;
|
|
|
|
bvec = &bio->bi_io_vec[bio->bi_vcnt];
|
|
bvec->bv_page = page;
|
|
bvec->bv_len = len;
|
|
bvec->bv_offset = offset;
|
|
bio->bi_vcnt++;
|
|
bio->bi_iter.bi_size += len;
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* bio_add_pc_page - attempt to add page to passthrough bio
|
|
* @q: the target queue
|
|
* @bio: destination bio
|
|
* @page: page to add
|
|
* @len: vec entry length
|
|
* @offset: vec entry offset
|
|
*
|
|
* Attempt to add a page to the bio_vec maplist. This can fail for a
|
|
* number of reasons, such as the bio being full or target block device
|
|
* limitations. The target block device must allow bio's up to PAGE_SIZE,
|
|
* so it is always possible to add a single page to an empty bio.
|
|
*
|
|
* This should only be used by passthrough bios.
|
|
*/
|
|
int bio_add_pc_page(struct request_queue *q, struct bio *bio,
|
|
struct page *page, unsigned int len, unsigned int offset)
|
|
{
|
|
bool same_page = false;
|
|
return bio_add_hw_page(q, bio, page, len, offset,
|
|
queue_max_hw_sectors(q), &same_page);
|
|
}
|
|
EXPORT_SYMBOL(bio_add_pc_page);
|
|
|
|
/**
|
|
* __bio_try_merge_page - try appending data to an existing bvec.
|
|
* @bio: destination bio
|
|
* @page: start page to add
|
|
* @len: length of the data to add
|
|
* @off: offset of the data relative to @page
|
|
* @same_page: return if the segment has been merged inside the same page
|
|
*
|
|
* Try to add the data at @page + @off to the last bvec of @bio. This is a
|
|
* useful optimisation for file systems with a block size smaller than the
|
|
* page size.
|
|
*
|
|
* Warn if (@len, @off) crosses pages in case that @same_page is true.
|
|
*
|
|
* Return %true on success or %false on failure.
|
|
*/
|
|
bool __bio_try_merge_page(struct bio *bio, struct page *page,
|
|
unsigned int len, unsigned int off, bool *same_page)
|
|
{
|
|
if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
|
|
return false;
|
|
|
|
if (bio->bi_vcnt > 0) {
|
|
struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
|
|
|
|
if (page_is_mergeable(bv, page, len, off, same_page)) {
|
|
if (bio->bi_iter.bi_size > UINT_MAX - len)
|
|
return false;
|
|
bv->bv_len += len;
|
|
bio->bi_iter.bi_size += len;
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__bio_try_merge_page);
|
|
|
|
/**
|
|
* __bio_add_page - add page(s) to a bio in a new segment
|
|
* @bio: destination bio
|
|
* @page: start page to add
|
|
* @len: length of the data to add, may cross pages
|
|
* @off: offset of the data relative to @page, may cross pages
|
|
*
|
|
* Add the data at @page + @off to @bio as a new bvec. The caller must ensure
|
|
* that @bio has space for another bvec.
|
|
*/
|
|
void __bio_add_page(struct bio *bio, struct page *page,
|
|
unsigned int len, unsigned int off)
|
|
{
|
|
struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt];
|
|
|
|
WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
|
|
WARN_ON_ONCE(bio_full(bio, len));
|
|
|
|
bv->bv_page = page;
|
|
bv->bv_offset = off;
|
|
bv->bv_len = len;
|
|
|
|
bio->bi_iter.bi_size += len;
|
|
bio->bi_vcnt++;
|
|
|
|
if (!bio_flagged(bio, BIO_WORKINGSET) && unlikely(PageWorkingset(page)))
|
|
bio_set_flag(bio, BIO_WORKINGSET);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__bio_add_page);
|
|
|
|
/**
|
|
* bio_add_page - attempt to add page(s) to bio
|
|
* @bio: destination bio
|
|
* @page: start page to add
|
|
* @len: vec entry length, may cross pages
|
|
* @offset: vec entry offset relative to @page, may cross pages
|
|
*
|
|
* Attempt to add page(s) to the bio_vec maplist. This will only fail
|
|
* if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
|
|
*/
|
|
int bio_add_page(struct bio *bio, struct page *page,
|
|
unsigned int len, unsigned int offset)
|
|
{
|
|
bool same_page = false;
|
|
|
|
if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) {
|
|
if (bio_full(bio, len))
|
|
return 0;
|
|
__bio_add_page(bio, page, len, offset);
|
|
}
|
|
return len;
|
|
}
|
|
EXPORT_SYMBOL(bio_add_page);
|
|
|
|
void bio_release_pages(struct bio *bio, bool mark_dirty)
|
|
{
|
|
struct bvec_iter_all iter_all;
|
|
struct bio_vec *bvec;
|
|
|
|
if (bio_flagged(bio, BIO_NO_PAGE_REF))
|
|
return;
|
|
|
|
bio_for_each_segment_all(bvec, bio, iter_all) {
|
|
if (mark_dirty && !PageCompound(bvec->bv_page))
|
|
set_page_dirty_lock(bvec->bv_page);
|
|
put_page(bvec->bv_page);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(bio_release_pages);
|
|
|
|
static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter)
|
|
{
|
|
const struct bio_vec *bv = iter->bvec;
|
|
unsigned int len;
|
|
size_t size;
|
|
|
|
if (WARN_ON_ONCE(iter->iov_offset > bv->bv_len))
|
|
return -EINVAL;
|
|
|
|
len = min_t(size_t, bv->bv_len - iter->iov_offset, iter->count);
|
|
size = bio_add_page(bio, bv->bv_page, len,
|
|
bv->bv_offset + iter->iov_offset);
|
|
if (unlikely(size != len))
|
|
return -EINVAL;
|
|
iov_iter_advance(iter, size);
|
|
return 0;
|
|
}
|
|
|
|
#define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))
|
|
|
|
/**
|
|
* __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
|
|
* @bio: bio to add pages to
|
|
* @iter: iov iterator describing the region to be mapped
|
|
*
|
|
* Pins pages from *iter and appends them to @bio's bvec array. The
|
|
* pages will have to be released using put_page() when done.
|
|
* For multi-segment *iter, this function only adds pages from the
|
|
* next non-empty segment of the iov iterator.
|
|
*/
|
|
static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
|
|
{
|
|
unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
|
|
unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
|
|
struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
|
|
struct page **pages = (struct page **)bv;
|
|
bool same_page = false;
|
|
ssize_t size, left;
|
|
unsigned len, i;
|
|
size_t offset;
|
|
|
|
/*
|
|
* Move page array up in the allocated memory for the bio vecs as far as
|
|
* possible so that we can start filling biovecs from the beginning
|
|
* without overwriting the temporary page array.
|
|
*/
|
|
BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
|
|
pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
|
|
|
|
size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
|
|
if (unlikely(size <= 0))
|
|
return size ? size : -EFAULT;
|
|
|
|
for (left = size, i = 0; left > 0; left -= len, i++) {
|
|
struct page *page = pages[i];
|
|
|
|
len = min_t(size_t, PAGE_SIZE - offset, left);
|
|
|
|
if (__bio_try_merge_page(bio, page, len, offset, &same_page)) {
|
|
if (same_page)
|
|
put_page(page);
|
|
} else {
|
|
if (WARN_ON_ONCE(bio_full(bio, len)))
|
|
return -EINVAL;
|
|
__bio_add_page(bio, page, len, offset);
|
|
}
|
|
offset = 0;
|
|
}
|
|
|
|
iov_iter_advance(iter, size);
|
|
return 0;
|
|
}
|
|
|
|
static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter)
|
|
{
|
|
unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
|
|
unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
|
|
struct request_queue *q = bio->bi_disk->queue;
|
|
unsigned int max_append_sectors = queue_max_zone_append_sectors(q);
|
|
struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
|
|
struct page **pages = (struct page **)bv;
|
|
ssize_t size, left;
|
|
unsigned len, i;
|
|
size_t offset;
|
|
|
|
if (WARN_ON_ONCE(!max_append_sectors))
|
|
return 0;
|
|
|
|
/*
|
|
* Move page array up in the allocated memory for the bio vecs as far as
|
|
* possible so that we can start filling biovecs from the beginning
|
|
* without overwriting the temporary page array.
|
|
*/
|
|
BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
|
|
pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
|
|
|
|
size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
|
|
if (unlikely(size <= 0))
|
|
return size ? size : -EFAULT;
|
|
|
|
for (left = size, i = 0; left > 0; left -= len, i++) {
|
|
struct page *page = pages[i];
|
|
bool same_page = false;
|
|
|
|
len = min_t(size_t, PAGE_SIZE - offset, left);
|
|
if (bio_add_hw_page(q, bio, page, len, offset,
|
|
max_append_sectors, &same_page) != len)
|
|
return -EINVAL;
|
|
if (same_page)
|
|
put_page(page);
|
|
offset = 0;
|
|
}
|
|
|
|
iov_iter_advance(iter, size);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bio_iov_iter_get_pages - add user or kernel pages to a bio
|
|
* @bio: bio to add pages to
|
|
* @iter: iov iterator describing the region to be added
|
|
*
|
|
* This takes either an iterator pointing to user memory, or one pointing to
|
|
* kernel pages (BVEC iterator). If we're adding user pages, we pin them and
|
|
* map them into the kernel. On IO completion, the caller should put those
|
|
* pages. If we're adding kernel pages, and the caller told us it's safe to
|
|
* do so, we just have to add the pages to the bio directly. We don't grab an
|
|
* extra reference to those pages (the user should already have that), and we
|
|
* don't put the page on IO completion. The caller needs to check if the bio is
|
|
* flagged BIO_NO_PAGE_REF on IO completion. If it isn't, then pages should be
|
|
* released.
|
|
*
|
|
* The function tries, but does not guarantee, to pin as many pages as
|
|
* fit into the bio, or are requested in *iter, whatever is smaller. If
|
|
* MM encounters an error pinning the requested pages, it stops. Error
|
|
* is returned only if 0 pages could be pinned.
|
|
*/
|
|
int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
|
|
{
|
|
const bool is_bvec = iov_iter_is_bvec(iter);
|
|
int ret;
|
|
|
|
if (WARN_ON_ONCE(bio->bi_vcnt))
|
|
return -EINVAL;
|
|
|
|
do {
|
|
if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
|
|
if (WARN_ON_ONCE(is_bvec))
|
|
return -EINVAL;
|
|
ret = __bio_iov_append_get_pages(bio, iter);
|
|
} else {
|
|
if (is_bvec)
|
|
ret = __bio_iov_bvec_add_pages(bio, iter);
|
|
else
|
|
ret = __bio_iov_iter_get_pages(bio, iter);
|
|
}
|
|
} while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));
|
|
|
|
if (is_bvec)
|
|
bio_set_flag(bio, BIO_NO_PAGE_REF);
|
|
return bio->bi_vcnt ? 0 : ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
|
|
|
|
static void submit_bio_wait_endio(struct bio *bio)
|
|
{
|
|
complete(bio->bi_private);
|
|
}
|
|
|
|
/**
|
|
* submit_bio_wait - submit a bio, and wait until it completes
|
|
* @bio: The &struct bio which describes the I/O
|
|
*
|
|
* Simple wrapper around submit_bio(). Returns 0 on success, or the error from
|
|
* bio_endio() on failure.
|
|
*
|
|
* WARNING: Unlike to how submit_bio() is usually used, this function does not
|
|
* result in bio reference to be consumed. The caller must drop the reference
|
|
* on his own.
|
|
*/
|
|
int submit_bio_wait(struct bio *bio)
|
|
{
|
|
DECLARE_COMPLETION_ONSTACK_MAP(done, bio->bi_disk->lockdep_map);
|
|
unsigned long hang_check;
|
|
|
|
bio->bi_private = &done;
|
|
bio->bi_end_io = submit_bio_wait_endio;
|
|
bio->bi_opf |= REQ_SYNC;
|
|
submit_bio(bio);
|
|
|
|
/* Prevent hang_check timer from firing at us during very long I/O */
|
|
hang_check = sysctl_hung_task_timeout_secs;
|
|
if (hang_check)
|
|
while (!wait_for_completion_io_timeout(&done,
|
|
hang_check * (HZ/2)))
|
|
;
|
|
else
|
|
wait_for_completion_io(&done);
|
|
|
|
return blk_status_to_errno(bio->bi_status);
|
|
}
|
|
EXPORT_SYMBOL(submit_bio_wait);
|
|
|
|
/**
|
|
* bio_advance - increment/complete a bio by some number of bytes
|
|
* @bio: bio to advance
|
|
* @bytes: number of bytes to complete
|
|
*
|
|
* This updates bi_sector, bi_size and bi_idx; if the number of bytes to
|
|
* complete doesn't align with a bvec boundary, then bv_len and bv_offset will
|
|
* be updated on the last bvec as well.
|
|
*
|
|
* @bio will then represent the remaining, uncompleted portion of the io.
|
|
*/
|
|
void bio_advance(struct bio *bio, unsigned bytes)
|
|
{
|
|
if (bio_integrity(bio))
|
|
bio_integrity_advance(bio, bytes);
|
|
|
|
bio_crypt_advance(bio, bytes);
|
|
bio_advance_iter(bio, &bio->bi_iter, bytes);
|
|
}
|
|
EXPORT_SYMBOL(bio_advance);
|
|
|
|
void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
|
|
struct bio *src, struct bvec_iter *src_iter)
|
|
{
|
|
struct bio_vec src_bv, dst_bv;
|
|
void *src_p, *dst_p;
|
|
unsigned bytes;
|
|
|
|
while (src_iter->bi_size && dst_iter->bi_size) {
|
|
src_bv = bio_iter_iovec(src, *src_iter);
|
|
dst_bv = bio_iter_iovec(dst, *dst_iter);
|
|
|
|
bytes = min(src_bv.bv_len, dst_bv.bv_len);
|
|
|
|
src_p = kmap_atomic(src_bv.bv_page);
|
|
dst_p = kmap_atomic(dst_bv.bv_page);
|
|
|
|
memcpy(dst_p + dst_bv.bv_offset,
|
|
src_p + src_bv.bv_offset,
|
|
bytes);
|
|
|
|
kunmap_atomic(dst_p);
|
|
kunmap_atomic(src_p);
|
|
|
|
flush_dcache_page(dst_bv.bv_page);
|
|
|
|
bio_advance_iter(src, src_iter, bytes);
|
|
bio_advance_iter(dst, dst_iter, bytes);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(bio_copy_data_iter);
|
|
|
|
/**
|
|
* bio_copy_data - copy contents of data buffers from one bio to another
|
|
* @src: source bio
|
|
* @dst: destination bio
|
|
*
|
|
* Stops when it reaches the end of either @src or @dst - that is, copies
|
|
* min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
|
|
*/
|
|
void bio_copy_data(struct bio *dst, struct bio *src)
|
|
{
|
|
struct bvec_iter src_iter = src->bi_iter;
|
|
struct bvec_iter dst_iter = dst->bi_iter;
|
|
|
|
bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
|
|
}
|
|
EXPORT_SYMBOL(bio_copy_data);
|
|
|
|
/**
|
|
* bio_list_copy_data - copy contents of data buffers from one chain of bios to
|
|
* another
|
|
* @src: source bio list
|
|
* @dst: destination bio list
|
|
*
|
|
* Stops when it reaches the end of either the @src list or @dst list - that is,
|
|
* copies min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of
|
|
* bios).
|
|
*/
|
|
void bio_list_copy_data(struct bio *dst, struct bio *src)
|
|
{
|
|
struct bvec_iter src_iter = src->bi_iter;
|
|
struct bvec_iter dst_iter = dst->bi_iter;
|
|
|
|
while (1) {
|
|
if (!src_iter.bi_size) {
|
|
src = src->bi_next;
|
|
if (!src)
|
|
break;
|
|
|
|
src_iter = src->bi_iter;
|
|
}
|
|
|
|
if (!dst_iter.bi_size) {
|
|
dst = dst->bi_next;
|
|
if (!dst)
|
|
break;
|
|
|
|
dst_iter = dst->bi_iter;
|
|
}
|
|
|
|
bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(bio_list_copy_data);
|
|
|
|
void bio_free_pages(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec;
|
|
struct bvec_iter_all iter_all;
|
|
|
|
bio_for_each_segment_all(bvec, bio, iter_all)
|
|
__free_page(bvec->bv_page);
|
|
}
|
|
EXPORT_SYMBOL(bio_free_pages);
|
|
|
|
/*
|
|
* bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
|
|
* for performing direct-IO in BIOs.
|
|
*
|
|
* The problem is that we cannot run set_page_dirty() from interrupt context
|
|
* because the required locks are not interrupt-safe. So what we can do is to
|
|
* mark the pages dirty _before_ performing IO. And in interrupt context,
|
|
* check that the pages are still dirty. If so, fine. If not, redirty them
|
|
* in process context.
|
|
*
|
|
* We special-case compound pages here: normally this means reads into hugetlb
|
|
* pages. The logic in here doesn't really work right for compound pages
|
|
* because the VM does not uniformly chase down the head page in all cases.
|
|
* But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
|
|
* handle them at all. So we skip compound pages here at an early stage.
|
|
*
|
|
* Note that this code is very hard to test under normal circumstances because
|
|
* direct-io pins the pages with get_user_pages(). This makes
|
|
* is_page_cache_freeable return false, and the VM will not clean the pages.
|
|
* But other code (eg, flusher threads) could clean the pages if they are mapped
|
|
* pagecache.
|
|
*
|
|
* Simply disabling the call to bio_set_pages_dirty() is a good way to test the
|
|
* deferred bio dirtying paths.
|
|
*/
|
|
|
|
/*
|
|
* bio_set_pages_dirty() will mark all the bio's pages as dirty.
|
|
*/
|
|
void bio_set_pages_dirty(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec;
|
|
struct bvec_iter_all iter_all;
|
|
|
|
bio_for_each_segment_all(bvec, bio, iter_all) {
|
|
if (!PageCompound(bvec->bv_page))
|
|
set_page_dirty_lock(bvec->bv_page);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
|
|
* If they are, then fine. If, however, some pages are clean then they must
|
|
* have been written out during the direct-IO read. So we take another ref on
|
|
* the BIO and re-dirty the pages in process context.
|
|
*
|
|
* It is expected that bio_check_pages_dirty() will wholly own the BIO from
|
|
* here on. It will run one put_page() against each page and will run one
|
|
* bio_put() against the BIO.
|
|
*/
|
|
|
|
static void bio_dirty_fn(struct work_struct *work);
|
|
|
|
static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
|
|
static DEFINE_SPINLOCK(bio_dirty_lock);
|
|
static struct bio *bio_dirty_list;
|
|
|
|
/*
|
|
* This runs in process context
|
|
*/
|
|
static void bio_dirty_fn(struct work_struct *work)
|
|
{
|
|
struct bio *bio, *next;
|
|
|
|
spin_lock_irq(&bio_dirty_lock);
|
|
next = bio_dirty_list;
|
|
bio_dirty_list = NULL;
|
|
spin_unlock_irq(&bio_dirty_lock);
|
|
|
|
while ((bio = next) != NULL) {
|
|
next = bio->bi_private;
|
|
|
|
bio_release_pages(bio, true);
|
|
bio_put(bio);
|
|
}
|
|
}
|
|
|
|
void bio_check_pages_dirty(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec;
|
|
unsigned long flags;
|
|
struct bvec_iter_all iter_all;
|
|
|
|
bio_for_each_segment_all(bvec, bio, iter_all) {
|
|
if (!PageDirty(bvec->bv_page) && !PageCompound(bvec->bv_page))
|
|
goto defer;
|
|
}
|
|
|
|
bio_release_pages(bio, false);
|
|
bio_put(bio);
|
|
return;
|
|
defer:
|
|
spin_lock_irqsave(&bio_dirty_lock, flags);
|
|
bio->bi_private = bio_dirty_list;
|
|
bio_dirty_list = bio;
|
|
spin_unlock_irqrestore(&bio_dirty_lock, flags);
|
|
schedule_work(&bio_dirty_work);
|
|
}
|
|
|
|
static inline bool bio_remaining_done(struct bio *bio)
|
|
{
|
|
/*
|
|
* If we're not chaining, then ->__bi_remaining is always 1 and
|
|
* we always end io on the first invocation.
|
|
*/
|
|
if (!bio_flagged(bio, BIO_CHAIN))
|
|
return true;
|
|
|
|
BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
|
|
|
|
if (atomic_dec_and_test(&bio->__bi_remaining)) {
|
|
bio_clear_flag(bio, BIO_CHAIN);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* bio_endio - end I/O on a bio
|
|
* @bio: bio
|
|
*
|
|
* Description:
|
|
* bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
|
|
* way to end I/O on a bio. No one should call bi_end_io() directly on a
|
|
* bio unless they own it and thus know that it has an end_io function.
|
|
*
|
|
* bio_endio() can be called several times on a bio that has been chained
|
|
* using bio_chain(). The ->bi_end_io() function will only be called the
|
|
* last time. At this point the BLK_TA_COMPLETE tracing event will be
|
|
* generated if BIO_TRACE_COMPLETION is set.
|
|
**/
|
|
void bio_endio(struct bio *bio)
|
|
{
|
|
again:
|
|
if (!bio_remaining_done(bio))
|
|
return;
|
|
if (!bio_integrity_endio(bio))
|
|
return;
|
|
|
|
if (bio->bi_disk)
|
|
rq_qos_done_bio(bio->bi_disk->queue, bio);
|
|
|
|
/*
|
|
* Need to have a real endio function for chained bios, otherwise
|
|
* various corner cases will break (like stacking block devices that
|
|
* save/restore bi_end_io) - however, we want to avoid unbounded
|
|
* recursion and blowing the stack. Tail call optimization would
|
|
* handle this, but compiling with frame pointers also disables
|
|
* gcc's sibling call optimization.
|
|
*/
|
|
if (bio->bi_end_io == bio_chain_endio) {
|
|
bio = __bio_chain_endio(bio);
|
|
goto again;
|
|
}
|
|
|
|
if (bio->bi_disk && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
|
|
trace_block_bio_complete(bio->bi_disk->queue, bio);
|
|
bio_clear_flag(bio, BIO_TRACE_COMPLETION);
|
|
}
|
|
|
|
blk_throtl_bio_endio(bio);
|
|
/* release cgroup info */
|
|
bio_uninit(bio);
|
|
if (bio->bi_end_io)
|
|
bio->bi_end_io(bio);
|
|
}
|
|
EXPORT_SYMBOL(bio_endio);
|
|
|
|
/**
|
|
* bio_split - split a bio
|
|
* @bio: bio to split
|
|
* @sectors: number of sectors to split from the front of @bio
|
|
* @gfp: gfp mask
|
|
* @bs: bio set to allocate from
|
|
*
|
|
* Allocates and returns a new bio which represents @sectors from the start of
|
|
* @bio, and updates @bio to represent the remaining sectors.
|
|
*
|
|
* Unless this is a discard request the newly allocated bio will point
|
|
* to @bio's bi_io_vec. It is the caller's responsibility to ensure that
|
|
* neither @bio nor @bs are freed before the split bio.
|
|
*/
|
|
struct bio *bio_split(struct bio *bio, int sectors,
|
|
gfp_t gfp, struct bio_set *bs)
|
|
{
|
|
struct bio *split;
|
|
|
|
BUG_ON(sectors <= 0);
|
|
BUG_ON(sectors >= bio_sectors(bio));
|
|
|
|
/* Zone append commands cannot be split */
|
|
if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))
|
|
return NULL;
|
|
|
|
split = bio_clone_fast(bio, gfp, bs);
|
|
if (!split)
|
|
return NULL;
|
|
|
|
split->bi_iter.bi_size = sectors << 9;
|
|
|
|
if (bio_integrity(split))
|
|
bio_integrity_trim(split);
|
|
|
|
bio_advance(bio, split->bi_iter.bi_size);
|
|
|
|
if (bio_flagged(bio, BIO_TRACE_COMPLETION))
|
|
bio_set_flag(split, BIO_TRACE_COMPLETION);
|
|
|
|
return split;
|
|
}
|
|
EXPORT_SYMBOL(bio_split);
|
|
|
|
/**
|
|
* bio_trim - trim a bio
|
|
* @bio: bio to trim
|
|
* @offset: number of sectors to trim from the front of @bio
|
|
* @size: size we want to trim @bio to, in sectors
|
|
*/
|
|
void bio_trim(struct bio *bio, int offset, int size)
|
|
{
|
|
/* 'bio' is a cloned bio which we need to trim to match
|
|
* the given offset and size.
|
|
*/
|
|
|
|
size <<= 9;
|
|
if (offset == 0 && size == bio->bi_iter.bi_size)
|
|
return;
|
|
|
|
bio_advance(bio, offset << 9);
|
|
bio->bi_iter.bi_size = size;
|
|
|
|
if (bio_integrity(bio))
|
|
bio_integrity_trim(bio);
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(bio_trim);
|
|
|
|
/*
|
|
* create memory pools for biovec's in a bio_set.
|
|
* use the global biovec slabs created for general use.
|
|
*/
|
|
int biovec_init_pool(mempool_t *pool, int pool_entries)
|
|
{
|
|
struct biovec_slab *bp = bvec_slabs + BVEC_POOL_MAX;
|
|
|
|
return mempool_init_slab_pool(pool, pool_entries, bp->slab);
|
|
}
|
|
|
|
/*
|
|
* bioset_exit - exit a bioset initialized with bioset_init()
|
|
*
|
|
* May be called on a zeroed but uninitialized bioset (i.e. allocated with
|
|
* kzalloc()).
|
|
*/
|
|
void bioset_exit(struct bio_set *bs)
|
|
{
|
|
if (bs->rescue_workqueue)
|
|
destroy_workqueue(bs->rescue_workqueue);
|
|
bs->rescue_workqueue = NULL;
|
|
|
|
mempool_exit(&bs->bio_pool);
|
|
mempool_exit(&bs->bvec_pool);
|
|
|
|
bioset_integrity_free(bs);
|
|
if (bs->bio_slab)
|
|
bio_put_slab(bs);
|
|
bs->bio_slab = NULL;
|
|
}
|
|
EXPORT_SYMBOL(bioset_exit);
|
|
|
|
/**
|
|
* bioset_init - Initialize a bio_set
|
|
* @bs: pool to initialize
|
|
* @pool_size: Number of bio and bio_vecs to cache in the mempool
|
|
* @front_pad: Number of bytes to allocate in front of the returned bio
|
|
* @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS
|
|
* and %BIOSET_NEED_RESCUER
|
|
*
|
|
* Description:
|
|
* Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
|
|
* to ask for a number of bytes to be allocated in front of the bio.
|
|
* Front pad allocation is useful for embedding the bio inside
|
|
* another structure, to avoid allocating extra data to go with the bio.
|
|
* Note that the bio must be embedded at the END of that structure always,
|
|
* or things will break badly.
|
|
* If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated
|
|
* for allocating iovecs. This pool is not needed e.g. for bio_clone_fast().
|
|
* If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used to
|
|
* dispatch queued requests when the mempool runs out of space.
|
|
*
|
|
*/
|
|
int bioset_init(struct bio_set *bs,
|
|
unsigned int pool_size,
|
|
unsigned int front_pad,
|
|
int flags)
|
|
{
|
|
unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
|
|
|
|
bs->front_pad = front_pad;
|
|
|
|
spin_lock_init(&bs->rescue_lock);
|
|
bio_list_init(&bs->rescue_list);
|
|
INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
|
|
|
|
bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
|
|
if (!bs->bio_slab)
|
|
return -ENOMEM;
|
|
|
|
if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab))
|
|
goto bad;
|
|
|
|
if ((flags & BIOSET_NEED_BVECS) &&
|
|
biovec_init_pool(&bs->bvec_pool, pool_size))
|
|
goto bad;
|
|
|
|
if (!(flags & BIOSET_NEED_RESCUER))
|
|
return 0;
|
|
|
|
bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
|
|
if (!bs->rescue_workqueue)
|
|
goto bad;
|
|
|
|
return 0;
|
|
bad:
|
|
bioset_exit(bs);
|
|
return -ENOMEM;
|
|
}
|
|
EXPORT_SYMBOL(bioset_init);
|
|
|
|
/*
|
|
* Initialize and setup a new bio_set, based on the settings from
|
|
* another bio_set.
|
|
*/
|
|
int bioset_init_from_src(struct bio_set *bs, struct bio_set *src)
|
|
{
|
|
int flags;
|
|
|
|
flags = 0;
|
|
if (src->bvec_pool.min_nr)
|
|
flags |= BIOSET_NEED_BVECS;
|
|
if (src->rescue_workqueue)
|
|
flags |= BIOSET_NEED_RESCUER;
|
|
|
|
return bioset_init(bs, src->bio_pool.min_nr, src->front_pad, flags);
|
|
}
|
|
EXPORT_SYMBOL(bioset_init_from_src);
|
|
|
|
static void __init biovec_init_slabs(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < BVEC_POOL_NR; i++) {
|
|
int size;
|
|
struct biovec_slab *bvs = bvec_slabs + i;
|
|
|
|
if (bvs->nr_vecs <= BIO_INLINE_VECS) {
|
|
bvs->slab = NULL;
|
|
continue;
|
|
}
|
|
|
|
size = bvs->nr_vecs * sizeof(struct bio_vec);
|
|
bvs->slab = kmem_cache_create(bvs->name, size, 0,
|
|
SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
|
|
}
|
|
}
|
|
|
|
static int __init init_bio(void)
|
|
{
|
|
bio_slab_max = 2;
|
|
bio_slab_nr = 0;
|
|
bio_slabs = kcalloc(bio_slab_max, sizeof(struct bio_slab),
|
|
GFP_KERNEL);
|
|
|
|
BUILD_BUG_ON(BIO_FLAG_LAST > BVEC_POOL_OFFSET);
|
|
|
|
if (!bio_slabs)
|
|
panic("bio: can't allocate bios\n");
|
|
|
|
bio_integrity_init();
|
|
biovec_init_slabs();
|
|
|
|
if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS))
|
|
panic("bio: can't allocate bios\n");
|
|
|
|
if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE))
|
|
panic("bio: can't create integrity pool\n");
|
|
|
|
return 0;
|
|
}
|
|
subsys_initcall(init_bio);
|