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![Jens Axboe](/assets/img/avatar_default.png)
The empty barrier patches do not carry data, so they have no iovec attached. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
1205 lines
28 KiB
C
1205 lines
28 KiB
C
/*
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* Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public Licens
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
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*
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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/slab.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mempool.h>
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#include <linux/workqueue.h>
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#include <linux/blktrace_api.h>
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#include <scsi/sg.h> /* for struct sg_iovec */
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#define BIO_POOL_SIZE 2
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static struct kmem_cache *bio_slab __read_mostly;
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#define BIOVEC_NR_POOLS 6
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/*
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* a small number of entries is fine, not going to be performance critical.
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* basically we just need to survive
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*/
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#define BIO_SPLIT_ENTRIES 2
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mempool_t *bio_split_pool __read_mostly;
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struct biovec_slab {
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int nr_vecs;
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char *name;
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struct kmem_cache *slab;
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};
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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) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
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static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
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BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
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};
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#undef BV
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/*
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* bio_set is used to allow other portions of the IO system to
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* allocate their own private memory pools for bio and iovec structures.
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* These memory pools in turn all allocate from the bio_slab
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* and the bvec_slabs[].
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*/
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struct bio_set {
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mempool_t *bio_pool;
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mempool_t *bvec_pools[BIOVEC_NR_POOLS];
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};
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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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static struct bio_set *fs_bio_set;
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static inline struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, struct bio_set *bs)
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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 : *idx = 0; break;
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case 2 ... 4: *idx = 1; break;
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case 5 ... 16: *idx = 2; break;
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case 17 ... 64: *idx = 3; break;
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case 65 ... 128: *idx = 4; break;
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case 129 ... BIO_MAX_PAGES: *idx = 5; 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
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*/
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bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask);
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if (bvl) {
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struct biovec_slab *bp = bvec_slabs + *idx;
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memset(bvl, 0, bp->nr_vecs * sizeof(struct bio_vec));
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}
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return bvl;
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}
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void bio_free(struct bio *bio, struct bio_set *bio_set)
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{
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if (bio->bi_io_vec) {
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const int pool_idx = BIO_POOL_IDX(bio);
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BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
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mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
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}
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mempool_free(bio, bio_set->bio_pool);
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}
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/*
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* default destructor for a bio allocated with bio_alloc_bioset()
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*/
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static void bio_fs_destructor(struct bio *bio)
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{
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bio_free(bio, fs_bio_set);
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}
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void bio_init(struct bio *bio)
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{
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memset(bio, 0, sizeof(*bio));
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bio->bi_flags = 1 << BIO_UPTODATE;
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atomic_set(&bio->bi_cnt, 1);
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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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* bio_alloc_bioset will first try it's on mempool to satisfy the allocation.
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* If %__GFP_WAIT is set then we will block on the internal pool waiting
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* for a &struct bio to become free.
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*
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* allocate bio and iovecs from the memory pools specified by the
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* bio_set structure.
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**/
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struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
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{
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struct bio *bio = mempool_alloc(bs->bio_pool, gfp_mask);
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if (likely(bio)) {
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struct bio_vec *bvl = NULL;
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bio_init(bio);
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if (likely(nr_iovecs)) {
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unsigned long idx = 0; /* shut up gcc */
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bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
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if (unlikely(!bvl)) {
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mempool_free(bio, bs->bio_pool);
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bio = NULL;
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goto out;
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}
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bio->bi_flags |= idx << BIO_POOL_OFFSET;
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bio->bi_max_vecs = bvec_slabs[idx].nr_vecs;
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}
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bio->bi_io_vec = bvl;
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}
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out:
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return bio;
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}
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struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
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{
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struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
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if (bio)
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bio->bi_destructor = bio_fs_destructor;
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return bio;
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}
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void zero_fill_bio(struct bio *bio)
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{
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unsigned long flags;
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struct bio_vec *bv;
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int i;
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bio_for_each_segment(bv, bio, i) {
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char *data = bvec_kmap_irq(bv, &flags);
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memset(data, 0, bv->bv_len);
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flush_dcache_page(bv->bv_page);
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bvec_kunmap_irq(data, &flags);
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}
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}
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EXPORT_SYMBOL(zero_fill_bio);
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/**
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* bio_put - release a reference to a bio
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* @bio: bio to release reference to
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*
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* Description:
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* Put a reference to a &struct bio, either one you have gotten with
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* bio_alloc or bio_get. The last put of a bio will free it.
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**/
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void bio_put(struct bio *bio)
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{
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BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
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/*
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* last put frees it
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*/
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if (atomic_dec_and_test(&bio->bi_cnt)) {
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bio->bi_next = NULL;
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bio->bi_destructor(bio);
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}
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}
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inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
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{
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if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
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blk_recount_segments(q, bio);
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return bio->bi_phys_segments;
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}
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inline int bio_hw_segments(struct request_queue *q, struct bio *bio)
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{
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if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
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blk_recount_segments(q, bio);
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return bio->bi_hw_segments;
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}
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/**
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* __bio_clone - clone a bio
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* @bio: destination bio
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* @bio_src: bio to clone
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*
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* Clone a &bio. Caller will own the returned bio, but not
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* the actual data it points to. Reference count of returned
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* bio will be one.
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*/
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void __bio_clone(struct bio *bio, struct bio *bio_src)
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{
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struct request_queue *q = bdev_get_queue(bio_src->bi_bdev);
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memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
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bio_src->bi_max_vecs * sizeof(struct bio_vec));
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bio->bi_sector = bio_src->bi_sector;
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bio->bi_bdev = bio_src->bi_bdev;
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bio->bi_flags |= 1 << BIO_CLONED;
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bio->bi_rw = bio_src->bi_rw;
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bio->bi_vcnt = bio_src->bi_vcnt;
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bio->bi_size = bio_src->bi_size;
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bio->bi_idx = bio_src->bi_idx;
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bio_phys_segments(q, bio);
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bio_hw_segments(q, bio);
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}
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/**
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* bio_clone - clone a bio
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* @bio: bio to clone
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* @gfp_mask: allocation priority
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*
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* Like __bio_clone, only also allocates the returned bio
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*/
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struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
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{
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struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
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if (b) {
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b->bi_destructor = bio_fs_destructor;
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__bio_clone(b, bio);
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}
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return b;
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}
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/**
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* bio_get_nr_vecs - return approx number of vecs
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* @bdev: I/O target
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*
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* Return the approximate number of pages we can send to this target.
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* There's no guarantee that you will be able to fit this number of pages
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* into a bio, it does not account for dynamic restrictions that vary
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* on offset.
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*/
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int bio_get_nr_vecs(struct block_device *bdev)
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{
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struct request_queue *q = bdev_get_queue(bdev);
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int nr_pages;
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nr_pages = ((q->max_sectors << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
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if (nr_pages > q->max_phys_segments)
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nr_pages = q->max_phys_segments;
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if (nr_pages > q->max_hw_segments)
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nr_pages = q->max_hw_segments;
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return nr_pages;
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}
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static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
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*page, unsigned int len, unsigned int offset,
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unsigned short max_sectors)
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{
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int retried_segments = 0;
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struct bio_vec *bvec;
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/*
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* cloned bio must not modify vec list
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*/
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if (unlikely(bio_flagged(bio, BIO_CLONED)))
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return 0;
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if (((bio->bi_size + len) >> 9) > max_sectors)
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return 0;
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/*
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* For filesystems with a blocksize smaller than the pagesize
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* we will often be called with the same page as last time and
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* a consecutive offset. Optimize this special case.
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*/
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if (bio->bi_vcnt > 0) {
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struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
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if (page == prev->bv_page &&
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offset == prev->bv_offset + prev->bv_len) {
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prev->bv_len += len;
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if (q->merge_bvec_fn &&
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q->merge_bvec_fn(q, bio, prev) < len) {
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prev->bv_len -= len;
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return 0;
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}
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goto done;
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}
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}
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if (bio->bi_vcnt >= bio->bi_max_vecs)
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return 0;
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/*
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* we might lose a segment or two here, but rather that than
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* make this too complex.
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*/
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while (bio->bi_phys_segments >= q->max_phys_segments
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|| bio->bi_hw_segments >= q->max_hw_segments
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|| BIOVEC_VIRT_OVERSIZE(bio->bi_size)) {
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if (retried_segments)
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return 0;
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retried_segments = 1;
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blk_recount_segments(q, bio);
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}
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/*
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* setup the new entry, we might clear it again later if we
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* cannot add the page
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*/
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bvec = &bio->bi_io_vec[bio->bi_vcnt];
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bvec->bv_page = page;
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bvec->bv_len = len;
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bvec->bv_offset = offset;
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/*
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* if queue has other restrictions (eg varying max sector size
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* depending on offset), it can specify a merge_bvec_fn in the
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* queue to get further control
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*/
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if (q->merge_bvec_fn) {
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/*
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* merge_bvec_fn() returns number of bytes it can accept
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* at this offset
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*/
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if (q->merge_bvec_fn(q, bio, bvec) < len) {
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bvec->bv_page = NULL;
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bvec->bv_len = 0;
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bvec->bv_offset = 0;
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return 0;
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}
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}
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/* If we may be able to merge these biovecs, force a recount */
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if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec) ||
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BIOVEC_VIRT_MERGEABLE(bvec-1, bvec)))
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bio->bi_flags &= ~(1 << BIO_SEG_VALID);
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bio->bi_vcnt++;
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bio->bi_phys_segments++;
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bio->bi_hw_segments++;
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done:
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bio->bi_size += len;
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return len;
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}
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/**
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* bio_add_pc_page - attempt to add page to bio
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* @q: the target queue
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* @bio: destination bio
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* @page: page to add
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* @len: vec entry length
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* @offset: vec entry offset
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*
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* Attempt to add a page to the bio_vec maplist. This can fail for a
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* number of reasons, such as the bio being full or target block
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* device limitations. The target block device must allow bio's
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* smaller than PAGE_SIZE, so it is always possible to add a single
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* page to an empty bio. This should only be used by REQ_PC bios.
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*/
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int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
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unsigned int len, unsigned int offset)
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{
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return __bio_add_page(q, bio, page, len, offset, q->max_hw_sectors);
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}
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/**
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* bio_add_page - attempt to add page to bio
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* @bio: destination bio
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* @page: page to add
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* @len: vec entry length
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* @offset: vec entry offset
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*
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* Attempt to add a page to the bio_vec maplist. This can fail for a
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* number of reasons, such as the bio being full or target block
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* device limitations. The target block device must allow bio's
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* smaller than PAGE_SIZE, so it is always possible to add a single
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* page to an empty bio.
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*/
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int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
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unsigned int offset)
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{
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struct request_queue *q = bdev_get_queue(bio->bi_bdev);
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return __bio_add_page(q, bio, page, len, offset, q->max_sectors);
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}
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struct bio_map_data {
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struct bio_vec *iovecs;
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void __user *userptr;
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};
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static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio)
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{
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memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
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bio->bi_private = bmd;
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}
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static void bio_free_map_data(struct bio_map_data *bmd)
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{
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kfree(bmd->iovecs);
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kfree(bmd);
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}
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static struct bio_map_data *bio_alloc_map_data(int nr_segs)
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{
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struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL);
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if (!bmd)
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return NULL;
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bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL);
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if (bmd->iovecs)
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return bmd;
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|
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kfree(bmd);
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return NULL;
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}
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|
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/**
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* bio_uncopy_user - finish previously mapped bio
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* @bio: bio being terminated
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*
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* Free pages allocated from bio_copy_user() and write back data
|
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* to user space in case of a read.
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*/
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int bio_uncopy_user(struct bio *bio)
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{
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struct bio_map_data *bmd = bio->bi_private;
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const int read = bio_data_dir(bio) == READ;
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struct bio_vec *bvec;
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int i, ret = 0;
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__bio_for_each_segment(bvec, bio, i, 0) {
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char *addr = page_address(bvec->bv_page);
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unsigned int len = bmd->iovecs[i].bv_len;
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|
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if (read && !ret && copy_to_user(bmd->userptr, addr, len))
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ret = -EFAULT;
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__free_page(bvec->bv_page);
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bmd->userptr += len;
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}
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bio_free_map_data(bmd);
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bio_put(bio);
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return ret;
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}
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|
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/**
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* bio_copy_user - copy user data to bio
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* @q: destination block queue
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* @uaddr: start of user address
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* @len: length in bytes
|
|
* @write_to_vm: bool indicating writing to pages or not
|
|
*
|
|
* Prepares and returns a bio for indirect user io, bouncing data
|
|
* to/from kernel pages as necessary. Must be paired with
|
|
* call bio_uncopy_user() on io completion.
|
|
*/
|
|
struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
|
|
unsigned int len, int write_to_vm)
|
|
{
|
|
unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
unsigned long start = uaddr >> PAGE_SHIFT;
|
|
struct bio_map_data *bmd;
|
|
struct bio_vec *bvec;
|
|
struct page *page;
|
|
struct bio *bio;
|
|
int i, ret;
|
|
|
|
bmd = bio_alloc_map_data(end - start);
|
|
if (!bmd)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
bmd->userptr = (void __user *) uaddr;
|
|
|
|
ret = -ENOMEM;
|
|
bio = bio_alloc(GFP_KERNEL, end - start);
|
|
if (!bio)
|
|
goto out_bmd;
|
|
|
|
bio->bi_rw |= (!write_to_vm << BIO_RW);
|
|
|
|
ret = 0;
|
|
while (len) {
|
|
unsigned int bytes = PAGE_SIZE;
|
|
|
|
if (bytes > len)
|
|
bytes = len;
|
|
|
|
page = alloc_page(q->bounce_gfp | GFP_KERNEL);
|
|
if (!page) {
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
|
|
if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
|
|
break;
|
|
|
|
len -= bytes;
|
|
}
|
|
|
|
if (ret)
|
|
goto cleanup;
|
|
|
|
/*
|
|
* success
|
|
*/
|
|
if (!write_to_vm) {
|
|
char __user *p = (char __user *) uaddr;
|
|
|
|
/*
|
|
* for a write, copy in data to kernel pages
|
|
*/
|
|
ret = -EFAULT;
|
|
bio_for_each_segment(bvec, bio, i) {
|
|
char *addr = page_address(bvec->bv_page);
|
|
|
|
if (copy_from_user(addr, p, bvec->bv_len))
|
|
goto cleanup;
|
|
p += bvec->bv_len;
|
|
}
|
|
}
|
|
|
|
bio_set_map_data(bmd, bio);
|
|
return bio;
|
|
cleanup:
|
|
bio_for_each_segment(bvec, bio, i)
|
|
__free_page(bvec->bv_page);
|
|
|
|
bio_put(bio);
|
|
out_bmd:
|
|
bio_free_map_data(bmd);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
static struct bio *__bio_map_user_iov(struct request_queue *q,
|
|
struct block_device *bdev,
|
|
struct sg_iovec *iov, int iov_count,
|
|
int write_to_vm)
|
|
{
|
|
int i, j;
|
|
int nr_pages = 0;
|
|
struct page **pages;
|
|
struct bio *bio;
|
|
int cur_page = 0;
|
|
int ret, offset;
|
|
|
|
for (i = 0; i < iov_count; i++) {
|
|
unsigned long uaddr = (unsigned long)iov[i].iov_base;
|
|
unsigned long len = iov[i].iov_len;
|
|
unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
unsigned long start = uaddr >> PAGE_SHIFT;
|
|
|
|
nr_pages += end - start;
|
|
/*
|
|
* buffer must be aligned to at least hardsector size for now
|
|
*/
|
|
if (uaddr & queue_dma_alignment(q))
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (!nr_pages)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
bio = bio_alloc(GFP_KERNEL, nr_pages);
|
|
if (!bio)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ret = -ENOMEM;
|
|
pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
|
|
if (!pages)
|
|
goto out;
|
|
|
|
for (i = 0; i < iov_count; i++) {
|
|
unsigned long uaddr = (unsigned long)iov[i].iov_base;
|
|
unsigned long len = iov[i].iov_len;
|
|
unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
unsigned long start = uaddr >> PAGE_SHIFT;
|
|
const int local_nr_pages = end - start;
|
|
const int page_limit = cur_page + local_nr_pages;
|
|
|
|
down_read(¤t->mm->mmap_sem);
|
|
ret = get_user_pages(current, current->mm, uaddr,
|
|
local_nr_pages,
|
|
write_to_vm, 0, &pages[cur_page], NULL);
|
|
up_read(¤t->mm->mmap_sem);
|
|
|
|
if (ret < local_nr_pages) {
|
|
ret = -EFAULT;
|
|
goto out_unmap;
|
|
}
|
|
|
|
offset = uaddr & ~PAGE_MASK;
|
|
for (j = cur_page; j < page_limit; j++) {
|
|
unsigned int bytes = PAGE_SIZE - offset;
|
|
|
|
if (len <= 0)
|
|
break;
|
|
|
|
if (bytes > len)
|
|
bytes = len;
|
|
|
|
/*
|
|
* sorry...
|
|
*/
|
|
if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
|
|
bytes)
|
|
break;
|
|
|
|
len -= bytes;
|
|
offset = 0;
|
|
}
|
|
|
|
cur_page = j;
|
|
/*
|
|
* release the pages we didn't map into the bio, if any
|
|
*/
|
|
while (j < page_limit)
|
|
page_cache_release(pages[j++]);
|
|
}
|
|
|
|
kfree(pages);
|
|
|
|
/*
|
|
* set data direction, and check if mapped pages need bouncing
|
|
*/
|
|
if (!write_to_vm)
|
|
bio->bi_rw |= (1 << BIO_RW);
|
|
|
|
bio->bi_bdev = bdev;
|
|
bio->bi_flags |= (1 << BIO_USER_MAPPED);
|
|
return bio;
|
|
|
|
out_unmap:
|
|
for (i = 0; i < nr_pages; i++) {
|
|
if(!pages[i])
|
|
break;
|
|
page_cache_release(pages[i]);
|
|
}
|
|
out:
|
|
kfree(pages);
|
|
bio_put(bio);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
/**
|
|
* bio_map_user - map user address into bio
|
|
* @q: the struct request_queue for the bio
|
|
* @bdev: destination block device
|
|
* @uaddr: start of user address
|
|
* @len: length in bytes
|
|
* @write_to_vm: bool indicating writing to pages or not
|
|
*
|
|
* Map the user space address into a bio suitable for io to a block
|
|
* device. Returns an error pointer in case of error.
|
|
*/
|
|
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
|
|
unsigned long uaddr, unsigned int len, int write_to_vm)
|
|
{
|
|
struct sg_iovec iov;
|
|
|
|
iov.iov_base = (void __user *)uaddr;
|
|
iov.iov_len = len;
|
|
|
|
return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm);
|
|
}
|
|
|
|
/**
|
|
* bio_map_user_iov - map user sg_iovec table into bio
|
|
* @q: the struct request_queue for the bio
|
|
* @bdev: destination block device
|
|
* @iov: the iovec.
|
|
* @iov_count: number of elements in the iovec
|
|
* @write_to_vm: bool indicating writing to pages or not
|
|
*
|
|
* Map the user space address into a bio suitable for io to a block
|
|
* device. Returns an error pointer in case of error.
|
|
*/
|
|
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
|
|
struct sg_iovec *iov, int iov_count,
|
|
int write_to_vm)
|
|
{
|
|
struct bio *bio;
|
|
|
|
bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm);
|
|
|
|
if (IS_ERR(bio))
|
|
return bio;
|
|
|
|
/*
|
|
* subtle -- if __bio_map_user() ended up bouncing a bio,
|
|
* it would normally disappear when its bi_end_io is run.
|
|
* however, we need it for the unmap, so grab an extra
|
|
* reference to it
|
|
*/
|
|
bio_get(bio);
|
|
|
|
return bio;
|
|
}
|
|
|
|
static void __bio_unmap_user(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec;
|
|
int i;
|
|
|
|
/*
|
|
* make sure we dirty pages we wrote to
|
|
*/
|
|
__bio_for_each_segment(bvec, bio, i, 0) {
|
|
if (bio_data_dir(bio) == READ)
|
|
set_page_dirty_lock(bvec->bv_page);
|
|
|
|
page_cache_release(bvec->bv_page);
|
|
}
|
|
|
|
bio_put(bio);
|
|
}
|
|
|
|
/**
|
|
* bio_unmap_user - unmap a bio
|
|
* @bio: the bio being unmapped
|
|
*
|
|
* Unmap a bio previously mapped by bio_map_user(). Must be called with
|
|
* a process context.
|
|
*
|
|
* bio_unmap_user() may sleep.
|
|
*/
|
|
void bio_unmap_user(struct bio *bio)
|
|
{
|
|
__bio_unmap_user(bio);
|
|
bio_put(bio);
|
|
}
|
|
|
|
static void bio_map_kern_endio(struct bio *bio, int err)
|
|
{
|
|
bio_put(bio);
|
|
}
|
|
|
|
|
|
static struct bio *__bio_map_kern(struct request_queue *q, void *data,
|
|
unsigned int len, gfp_t gfp_mask)
|
|
{
|
|
unsigned long kaddr = (unsigned long)data;
|
|
unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
unsigned long start = kaddr >> PAGE_SHIFT;
|
|
const int nr_pages = end - start;
|
|
int offset, i;
|
|
struct bio *bio;
|
|
|
|
bio = bio_alloc(gfp_mask, nr_pages);
|
|
if (!bio)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
offset = offset_in_page(kaddr);
|
|
for (i = 0; i < nr_pages; i++) {
|
|
unsigned int bytes = PAGE_SIZE - offset;
|
|
|
|
if (len <= 0)
|
|
break;
|
|
|
|
if (bytes > len)
|
|
bytes = len;
|
|
|
|
if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
|
|
offset) < bytes)
|
|
break;
|
|
|
|
data += bytes;
|
|
len -= bytes;
|
|
offset = 0;
|
|
}
|
|
|
|
bio->bi_end_io = bio_map_kern_endio;
|
|
return bio;
|
|
}
|
|
|
|
/**
|
|
* bio_map_kern - map kernel address into bio
|
|
* @q: the struct request_queue for the bio
|
|
* @data: pointer to buffer to map
|
|
* @len: length in bytes
|
|
* @gfp_mask: allocation flags for bio allocation
|
|
*
|
|
* Map the kernel address into a bio suitable for io to a block
|
|
* device. Returns an error pointer in case of error.
|
|
*/
|
|
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
|
|
gfp_t gfp_mask)
|
|
{
|
|
struct bio *bio;
|
|
|
|
bio = __bio_map_kern(q, data, len, gfp_mask);
|
|
if (IS_ERR(bio))
|
|
return bio;
|
|
|
|
if (bio->bi_size == len)
|
|
return bio;
|
|
|
|
/*
|
|
* Don't support partial mappings.
|
|
*/
|
|
bio_put(bio);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
/*
|
|
* 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, pdflush) 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 = bio->bi_io_vec;
|
|
int i;
|
|
|
|
for (i = 0; i < bio->bi_vcnt; i++) {
|
|
struct page *page = bvec[i].bv_page;
|
|
|
|
if (page && !PageCompound(page))
|
|
set_page_dirty_lock(page);
|
|
}
|
|
}
|
|
|
|
void bio_release_pages(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec = bio->bi_io_vec;
|
|
int i;
|
|
|
|
for (i = 0; i < bio->bi_vcnt; i++) {
|
|
struct page *page = bvec[i].bv_page;
|
|
|
|
if (page)
|
|
put_page(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 the offending pages 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 page_cache_release() 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)
|
|
{
|
|
unsigned long flags;
|
|
struct bio *bio;
|
|
|
|
spin_lock_irqsave(&bio_dirty_lock, flags);
|
|
bio = bio_dirty_list;
|
|
bio_dirty_list = NULL;
|
|
spin_unlock_irqrestore(&bio_dirty_lock, flags);
|
|
|
|
while (bio) {
|
|
struct bio *next = bio->bi_private;
|
|
|
|
bio_set_pages_dirty(bio);
|
|
bio_release_pages(bio);
|
|
bio_put(bio);
|
|
bio = next;
|
|
}
|
|
}
|
|
|
|
void bio_check_pages_dirty(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec = bio->bi_io_vec;
|
|
int nr_clean_pages = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < bio->bi_vcnt; i++) {
|
|
struct page *page = bvec[i].bv_page;
|
|
|
|
if (PageDirty(page) || PageCompound(page)) {
|
|
page_cache_release(page);
|
|
bvec[i].bv_page = NULL;
|
|
} else {
|
|
nr_clean_pages++;
|
|
}
|
|
}
|
|
|
|
if (nr_clean_pages) {
|
|
unsigned long flags;
|
|
|
|
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);
|
|
} else {
|
|
bio_put(bio);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* bio_endio - end I/O on a bio
|
|
* @bio: bio
|
|
* @error: error, if any
|
|
*
|
|
* Description:
|
|
* bio_endio() will end I/O on the whole bio. bio_endio() is the
|
|
* preferred way to end I/O on a bio, it takes care of clearing
|
|
* BIO_UPTODATE on error. @error is 0 on success, and and one of the
|
|
* established -Exxxx (-EIO, for instance) error values in case
|
|
* something went wrong. Noone should call bi_end_io() directly on a
|
|
* bio unless they own it and thus know that it has an end_io
|
|
* function.
|
|
**/
|
|
void bio_endio(struct bio *bio, int error)
|
|
{
|
|
if (error)
|
|
clear_bit(BIO_UPTODATE, &bio->bi_flags);
|
|
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
|
|
error = -EIO;
|
|
|
|
if (bio->bi_end_io)
|
|
bio->bi_end_io(bio, error);
|
|
}
|
|
|
|
void bio_pair_release(struct bio_pair *bp)
|
|
{
|
|
if (atomic_dec_and_test(&bp->cnt)) {
|
|
struct bio *master = bp->bio1.bi_private;
|
|
|
|
bio_endio(master, bp->error);
|
|
mempool_free(bp, bp->bio2.bi_private);
|
|
}
|
|
}
|
|
|
|
static void bio_pair_end_1(struct bio *bi, int err)
|
|
{
|
|
struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
|
|
|
|
if (err)
|
|
bp->error = err;
|
|
|
|
bio_pair_release(bp);
|
|
}
|
|
|
|
static void bio_pair_end_2(struct bio *bi, int err)
|
|
{
|
|
struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
|
|
|
|
if (err)
|
|
bp->error = err;
|
|
|
|
bio_pair_release(bp);
|
|
}
|
|
|
|
/*
|
|
* split a bio - only worry about a bio with a single page
|
|
* in it's iovec
|
|
*/
|
|
struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors)
|
|
{
|
|
struct bio_pair *bp = mempool_alloc(pool, GFP_NOIO);
|
|
|
|
if (!bp)
|
|
return bp;
|
|
|
|
blk_add_trace_pdu_int(bdev_get_queue(bi->bi_bdev), BLK_TA_SPLIT, bi,
|
|
bi->bi_sector + first_sectors);
|
|
|
|
BUG_ON(bi->bi_vcnt != 1);
|
|
BUG_ON(bi->bi_idx != 0);
|
|
atomic_set(&bp->cnt, 3);
|
|
bp->error = 0;
|
|
bp->bio1 = *bi;
|
|
bp->bio2 = *bi;
|
|
bp->bio2.bi_sector += first_sectors;
|
|
bp->bio2.bi_size -= first_sectors << 9;
|
|
bp->bio1.bi_size = first_sectors << 9;
|
|
|
|
bp->bv1 = bi->bi_io_vec[0];
|
|
bp->bv2 = bi->bi_io_vec[0];
|
|
bp->bv2.bv_offset += first_sectors << 9;
|
|
bp->bv2.bv_len -= first_sectors << 9;
|
|
bp->bv1.bv_len = first_sectors << 9;
|
|
|
|
bp->bio1.bi_io_vec = &bp->bv1;
|
|
bp->bio2.bi_io_vec = &bp->bv2;
|
|
|
|
bp->bio1.bi_max_vecs = 1;
|
|
bp->bio2.bi_max_vecs = 1;
|
|
|
|
bp->bio1.bi_end_io = bio_pair_end_1;
|
|
bp->bio2.bi_end_io = bio_pair_end_2;
|
|
|
|
bp->bio1.bi_private = bi;
|
|
bp->bio2.bi_private = pool;
|
|
|
|
return bp;
|
|
}
|
|
|
|
|
|
/*
|
|
* create memory pools for biovec's in a bio_set.
|
|
* use the global biovec slabs created for general use.
|
|
*/
|
|
static int biovec_create_pools(struct bio_set *bs, int pool_entries)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < BIOVEC_NR_POOLS; i++) {
|
|
struct biovec_slab *bp = bvec_slabs + i;
|
|
mempool_t **bvp = bs->bvec_pools + i;
|
|
|
|
*bvp = mempool_create_slab_pool(pool_entries, bp->slab);
|
|
if (!*bvp)
|
|
return -ENOMEM;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void biovec_free_pools(struct bio_set *bs)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < BIOVEC_NR_POOLS; i++) {
|
|
mempool_t *bvp = bs->bvec_pools[i];
|
|
|
|
if (bvp)
|
|
mempool_destroy(bvp);
|
|
}
|
|
|
|
}
|
|
|
|
void bioset_free(struct bio_set *bs)
|
|
{
|
|
if (bs->bio_pool)
|
|
mempool_destroy(bs->bio_pool);
|
|
|
|
biovec_free_pools(bs);
|
|
|
|
kfree(bs);
|
|
}
|
|
|
|
struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size)
|
|
{
|
|
struct bio_set *bs = kzalloc(sizeof(*bs), GFP_KERNEL);
|
|
|
|
if (!bs)
|
|
return NULL;
|
|
|
|
bs->bio_pool = mempool_create_slab_pool(bio_pool_size, bio_slab);
|
|
if (!bs->bio_pool)
|
|
goto bad;
|
|
|
|
if (!biovec_create_pools(bs, bvec_pool_size))
|
|
return bs;
|
|
|
|
bad:
|
|
bioset_free(bs);
|
|
return NULL;
|
|
}
|
|
|
|
static void __init biovec_init_slabs(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < BIOVEC_NR_POOLS; i++) {
|
|
int size;
|
|
struct biovec_slab *bvs = bvec_slabs + i;
|
|
|
|
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 = KMEM_CACHE(bio, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
|
|
|
|
biovec_init_slabs();
|
|
|
|
fs_bio_set = bioset_create(BIO_POOL_SIZE, 2);
|
|
if (!fs_bio_set)
|
|
panic("bio: can't allocate bios\n");
|
|
|
|
bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
|
|
sizeof(struct bio_pair));
|
|
if (!bio_split_pool)
|
|
panic("bio: can't create split pool\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
subsys_initcall(init_bio);
|
|
|
|
EXPORT_SYMBOL(bio_alloc);
|
|
EXPORT_SYMBOL(bio_put);
|
|
EXPORT_SYMBOL(bio_free);
|
|
EXPORT_SYMBOL(bio_endio);
|
|
EXPORT_SYMBOL(bio_init);
|
|
EXPORT_SYMBOL(__bio_clone);
|
|
EXPORT_SYMBOL(bio_clone);
|
|
EXPORT_SYMBOL(bio_phys_segments);
|
|
EXPORT_SYMBOL(bio_hw_segments);
|
|
EXPORT_SYMBOL(bio_add_page);
|
|
EXPORT_SYMBOL(bio_add_pc_page);
|
|
EXPORT_SYMBOL(bio_get_nr_vecs);
|
|
EXPORT_SYMBOL(bio_map_kern);
|
|
EXPORT_SYMBOL(bio_pair_release);
|
|
EXPORT_SYMBOL(bio_split);
|
|
EXPORT_SYMBOL(bio_split_pool);
|
|
EXPORT_SYMBOL(bio_copy_user);
|
|
EXPORT_SYMBOL(bio_uncopy_user);
|
|
EXPORT_SYMBOL(bioset_create);
|
|
EXPORT_SYMBOL(bioset_free);
|
|
EXPORT_SYMBOL(bio_alloc_bioset);
|