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1753 lines
47 KiB
1753 lines
47 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2001 Jens Axboe <[email protected]> |
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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 <linux/xarray.h> |
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|
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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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struct bio_alloc_cache { |
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struct bio_list free_list; |
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unsigned int nr; |
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}; |
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|
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static 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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} bvec_slabs[] __read_mostly = { |
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{ .nr_vecs = 16, .name = "biovec-16" }, |
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{ .nr_vecs = 64, .name = "biovec-64" }, |
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{ .nr_vecs = 128, .name = "biovec-128" }, |
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{ .nr_vecs = BIO_MAX_VECS, .name = "biovec-max" }, |
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}; |
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|
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static struct biovec_slab *biovec_slab(unsigned short nr_vecs) |
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{ |
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switch (nr_vecs) { |
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/* smaller bios use inline vecs */ |
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case 5 ... 16: |
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return &bvec_slabs[0]; |
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case 17 ... 64: |
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return &bvec_slabs[1]; |
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case 65 ... 128: |
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return &bvec_slabs[2]; |
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case 129 ... BIO_MAX_VECS: |
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return &bvec_slabs[3]; |
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default: |
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BUG(); |
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return NULL; |
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} |
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} |
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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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struct bio_set fs_bio_set; |
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EXPORT_SYMBOL(fs_bio_set); |
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|
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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 DEFINE_XARRAY(bio_slabs); |
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|
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static struct bio_slab *create_bio_slab(unsigned int size) |
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{ |
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struct bio_slab *bslab = kzalloc(sizeof(*bslab), GFP_KERNEL); |
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|
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if (!bslab) |
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return NULL; |
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|
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snprintf(bslab->name, sizeof(bslab->name), "bio-%d", size); |
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bslab->slab = kmem_cache_create(bslab->name, size, |
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ARCH_KMALLOC_MINALIGN, SLAB_HWCACHE_ALIGN, NULL); |
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if (!bslab->slab) |
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goto fail_alloc_slab; |
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|
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bslab->slab_ref = 1; |
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bslab->slab_size = size; |
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|
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if (!xa_err(xa_store(&bio_slabs, size, bslab, GFP_KERNEL))) |
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return bslab; |
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|
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kmem_cache_destroy(bslab->slab); |
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|
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fail_alloc_slab: |
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kfree(bslab); |
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return NULL; |
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} |
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|
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static inline unsigned int bs_bio_slab_size(struct bio_set *bs) |
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{ |
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return bs->front_pad + sizeof(struct bio) + bs->back_pad; |
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} |
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|
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static struct kmem_cache *bio_find_or_create_slab(struct bio_set *bs) |
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{ |
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unsigned int size = bs_bio_slab_size(bs); |
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struct bio_slab *bslab; |
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|
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mutex_lock(&bio_slab_lock); |
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bslab = xa_load(&bio_slabs, size); |
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if (bslab) |
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bslab->slab_ref++; |
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else |
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bslab = create_bio_slab(size); |
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mutex_unlock(&bio_slab_lock); |
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|
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if (bslab) |
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return bslab->slab; |
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return NULL; |
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} |
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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 slab_size = bs_bio_slab_size(bs); |
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|
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mutex_lock(&bio_slab_lock); |
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|
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bslab = xa_load(&bio_slabs, slab_size); |
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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_ONCE(bslab->slab != bs->bio_slab); |
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|
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WARN_ON(!bslab->slab_ref); |
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|
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if (--bslab->slab_ref) |
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goto out; |
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xa_erase(&bio_slabs, slab_size); |
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|
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kmem_cache_destroy(bslab->slab); |
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kfree(bslab); |
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|
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out: |
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mutex_unlock(&bio_slab_lock); |
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} |
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|
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void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs) |
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{ |
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BIO_BUG_ON(nr_vecs > BIO_MAX_VECS); |
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|
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if (nr_vecs == BIO_MAX_VECS) |
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mempool_free(bv, pool); |
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else if (nr_vecs > BIO_INLINE_VECS) |
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kmem_cache_free(biovec_slab(nr_vecs)->slab, bv); |
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} |
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|
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/* |
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* Make the first allocation restricted and don't dump info on allocation |
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* failures, since we'll fall back to the mempool in case of failure. |
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*/ |
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static inline gfp_t bvec_alloc_gfp(gfp_t gfp) |
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{ |
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return (gfp & ~(__GFP_DIRECT_RECLAIM | __GFP_IO)) | |
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__GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; |
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} |
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|
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struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs, |
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gfp_t gfp_mask) |
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{ |
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struct biovec_slab *bvs = biovec_slab(*nr_vecs); |
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|
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if (WARN_ON_ONCE(!bvs)) |
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return NULL; |
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|
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/* |
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* Upgrade the nr_vecs request to take full advantage of the allocation. |
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* We also rely on this in the bvec_free path. |
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*/ |
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*nr_vecs = bvs->nr_vecs; |
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|
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/* |
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* Try a slab allocation first for all smaller allocations. If that |
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* fails and __GFP_DIRECT_RECLAIM is set retry with the mempool. |
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* The mempool is sized to handle up to BIO_MAX_VECS entries. |
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*/ |
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if (*nr_vecs < BIO_MAX_VECS) { |
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struct bio_vec *bvl; |
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|
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bvl = kmem_cache_alloc(bvs->slab, bvec_alloc_gfp(gfp_mask)); |
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if (likely(bvl) || !(gfp_mask & __GFP_DIRECT_RECLAIM)) |
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return bvl; |
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*nr_vecs = BIO_MAX_VECS; |
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} |
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|
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return mempool_alloc(pool, gfp_mask); |
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} |
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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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|
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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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|
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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, bio->bi_max_vecs); |
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|
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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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|
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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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/* |
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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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bio->bi_next = NULL; |
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bio->bi_bdev = NULL; |
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bio->bi_opf = 0; |
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bio->bi_flags = 0; |
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bio->bi_ioprio = 0; |
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bio->bi_write_hint = 0; |
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bio->bi_status = 0; |
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bio->bi_iter.bi_sector = 0; |
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bio->bi_iter.bi_size = 0; |
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bio->bi_iter.bi_idx = 0; |
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bio->bi_iter.bi_bvec_done = 0; |
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bio->bi_end_io = NULL; |
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bio->bi_private = NULL; |
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#ifdef CONFIG_BLK_CGROUP |
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bio->bi_blkg = NULL; |
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bio->bi_issue.value = 0; |
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#ifdef CONFIG_BLK_CGROUP_IOCOST |
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bio->bi_iocost_cost = 0; |
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#endif |
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#endif |
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#ifdef CONFIG_BLK_INLINE_ENCRYPTION |
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bio->bi_crypt_context = NULL; |
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#endif |
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#ifdef CONFIG_BLK_DEV_INTEGRITY |
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bio->bi_integrity = NULL; |
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#endif |
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bio->bi_vcnt = 0; |
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|
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atomic_set(&bio->__bi_remaining, 1); |
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atomic_set(&bio->__bi_cnt, 1); |
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|
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bio->bi_max_vecs = max_vecs; |
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bio->bi_io_vec = table; |
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bio->bi_pool = NULL; |
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} |
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EXPORT_SYMBOL(bio_init); |
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|
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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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bio_uninit(bio); |
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memset(bio, 0, BIO_RESET_BYTES); |
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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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|
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if (bio->bi_status && !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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|
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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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/** |
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* bio_chain - chain bio completions |
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* @bio: the target bio |
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* @parent: the parent bio of @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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|
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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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|
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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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|
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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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|
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if (!bio) |
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break; |
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|
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submit_bio_noacct(bio); |
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} |
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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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|
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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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|
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bio_list_init(&punt); |
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bio_list_init(&nopunt); |
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|
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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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|
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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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|
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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 |
|
* @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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* Allocate a bio from the mempools in @bs. |
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* |
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* If %__GFP_DIRECT_RECLAIM is set then bio_alloc will always be able to |
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* allocate a bio. This is due to the mempool guarantees. To make this work, |
|
* callers must never allocate more than 1 bio at a time from the general pool. |
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* Callers that need to allocate more than 1 bio must always submit the |
|
* previously allocated bio for IO before attempting to allocate a new one. |
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* Failure to do so can cause deadlocks under memory pressure. |
|
* |
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* Note that when running under submit_bio_noacct() (i.e. any block driver), |
|
* bios are not submitted until after you return - see the code in |
|
* submit_bio_noacct() that converts recursion into iteration, to prevent |
|
* stack overflows. |
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* |
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* This would normally mean allocating multiple bios under submit_bio_noacct() |
|
* would be susceptible to deadlocks, but we have |
|
* 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 |
|
* 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: Pointer to new bio on success, NULL on failure. |
|
*/ |
|
struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned short 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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struct bio *bio; |
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void *p; |
|
|
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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) && nr_iovecs > 0)) |
|
return NULL; |
|
|
|
/* |
|
* submit_bio_noacct() converts recursion to iteration; this means if |
|
* we're running beneath it, any bios we allocate and submit will not be |
|
* submitted (and thus freed) until after we return. |
|
* |
|
* This exposes us to a potential deadlock if we allocate 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 |
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* mempool's reserve. |
|
* |
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* 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 |
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* __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) { |
|
punt_bios_to_rescuer(bs); |
|
gfp_mask = saved_gfp; |
|
p = mempool_alloc(&bs->bio_pool, gfp_mask); |
|
} |
|
if (unlikely(!p)) |
|
return NULL; |
|
|
|
bio = p + bs->front_pad; |
|
if (nr_iovecs > BIO_INLINE_VECS) { |
|
struct bio_vec *bvl = NULL; |
|
|
|
bvl = bvec_alloc(&bs->bvec_pool, &nr_iovecs, gfp_mask); |
|
if (!bvl && gfp_mask != saved_gfp) { |
|
punt_bios_to_rescuer(bs); |
|
gfp_mask = saved_gfp; |
|
bvl = bvec_alloc(&bs->bvec_pool, &nr_iovecs, gfp_mask); |
|
} |
|
if (unlikely(!bvl)) |
|
goto err_free; |
|
|
|
bio_init(bio, bvl, nr_iovecs); |
|
} else if (nr_iovecs) { |
|
bio_init(bio, bio->bi_inline_vecs, BIO_INLINE_VECS); |
|
} else { |
|
bio_init(bio, NULL, 0); |
|
} |
|
|
|
bio->bi_pool = bs; |
|
return bio; |
|
|
|
err_free: |
|
mempool_free(p, &bs->bio_pool); |
|
return NULL; |
|
} |
|
EXPORT_SYMBOL(bio_alloc_bioset); |
|
|
|
/** |
|
* bio_kmalloc - kmalloc a bio for I/O |
|
* @gfp_mask: the GFP_* mask given to the slab allocator |
|
* @nr_iovecs: number of iovecs to pre-allocate |
|
* |
|
* Use kmalloc to allocate and initialize a bio. |
|
* |
|
* Returns: Pointer to new bio on success, NULL on failure. |
|
*/ |
|
struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned short nr_iovecs) |
|
{ |
|
struct bio *bio; |
|
|
|
if (nr_iovecs > UIO_MAXIOV) |
|
return NULL; |
|
|
|
bio = kmalloc(struct_size(bio, bi_inline_vecs, nr_iovecs), gfp_mask); |
|
if (unlikely(!bio)) |
|
return NULL; |
|
bio_init(bio, nr_iovecs ? bio->bi_inline_vecs : NULL, nr_iovecs); |
|
bio->bi_pool = NULL; |
|
return bio; |
|
} |
|
EXPORT_SYMBOL(bio_kmalloc); |
|
|
|
void zero_fill_bio(struct bio *bio) |
|
{ |
|
struct bio_vec bv; |
|
struct bvec_iter iter; |
|
|
|
bio_for_each_segment(bv, bio, iter) |
|
memzero_bvec(&bv); |
|
} |
|
EXPORT_SYMBOL(zero_fill_bio); |
|
|
|
/** |
|
* 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 = bdev_nr_sectors(bio->bi_bdev); |
|
|
|
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); |
|
} |
|
|
|
#define ALLOC_CACHE_MAX 512 |
|
#define ALLOC_CACHE_SLACK 64 |
|
|
|
static void bio_alloc_cache_prune(struct bio_alloc_cache *cache, |
|
unsigned int nr) |
|
{ |
|
unsigned int i = 0; |
|
struct bio *bio; |
|
|
|
while ((bio = bio_list_pop(&cache->free_list)) != NULL) { |
|
cache->nr--; |
|
bio_free(bio); |
|
if (++i == nr) |
|
break; |
|
} |
|
} |
|
|
|
static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node) |
|
{ |
|
struct bio_set *bs; |
|
|
|
bs = hlist_entry_safe(node, struct bio_set, cpuhp_dead); |
|
if (bs->cache) { |
|
struct bio_alloc_cache *cache = per_cpu_ptr(bs->cache, cpu); |
|
|
|
bio_alloc_cache_prune(cache, -1U); |
|
} |
|
return 0; |
|
} |
|
|
|
static void bio_alloc_cache_destroy(struct bio_set *bs) |
|
{ |
|
int cpu; |
|
|
|
if (!bs->cache) |
|
return; |
|
|
|
cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead); |
|
for_each_possible_cpu(cpu) { |
|
struct bio_alloc_cache *cache; |
|
|
|
cache = per_cpu_ptr(bs->cache, cpu); |
|
bio_alloc_cache_prune(cache, -1U); |
|
} |
|
free_percpu(bs->cache); |
|
} |
|
|
|
/** |
|
* 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 (unlikely(bio_flagged(bio, BIO_REFFED))) { |
|
BIO_BUG_ON(!atomic_read(&bio->__bi_cnt)); |
|
if (!atomic_dec_and_test(&bio->__bi_cnt)) |
|
return; |
|
} |
|
|
|
if (bio_flagged(bio, BIO_PERCPU_CACHE)) { |
|
struct bio_alloc_cache *cache; |
|
|
|
bio_uninit(bio); |
|
cache = per_cpu_ptr(bio->bi_pool->cache, get_cpu()); |
|
bio_list_add_head(&cache->free_list, bio); |
|
if (++cache->nr > ALLOC_CACHE_MAX + ALLOC_CACHE_SLACK) |
|
bio_alloc_cache_prune(cache, ALLOC_CACHE_SLACK); |
|
put_cpu(); |
|
} else { |
|
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) |
|
{ |
|
WARN_ON_ONCE(bio->bi_pool && bio->bi_max_vecs); |
|
|
|
/* |
|
* most users will be overriding ->bi_bdev with a new target, |
|
* so we don't set nor calculate new physical/hw segment counts here |
|
*/ |
|
bio->bi_bdev = bio_src->bi_bdev; |
|
bio_set_flag(bio, BIO_CLONED); |
|
if (bio_flagged(bio_src, BIO_THROTTLED)) |
|
bio_set_flag(bio, BIO_THROTTLED); |
|
if (bio_flagged(bio_src, BIO_REMAPPED)) |
|
bio_set_flag(bio, BIO_REMAPPED); |
|
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); |
|
|
|
if (bio_crypt_clone(b, bio, gfp_mask) < 0) |
|
goto err_put; |
|
|
|
if (bio_integrity(bio) && |
|
bio_integrity_clone(b, bio, gfp_mask) < 0) |
|
goto err_put; |
|
|
|
return b; |
|
|
|
err_put: |
|
bio_put(b); |
|
return NULL; |
|
} |
|
EXPORT_SYMBOL(bio_clone_fast); |
|
|
|
const char *bio_devname(struct bio *bio, char *buf) |
|
{ |
|
return bdevname(bio->bi_bdev, 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_add_zone_append_page - attempt to add page to zone-append bio |
|
* @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 of a bio that will be submitted |
|
* for a zone-append request. This can fail for a number of reasons, such as the |
|
* bio being full or the target block device is not a zoned block device or |
|
* other limitations of the target block device. 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. |
|
* |
|
* Returns: number of bytes added to the bio, or 0 in case of a failure. |
|
*/ |
|
int bio_add_zone_append_page(struct bio *bio, struct page *page, |
|
unsigned int len, unsigned int offset) |
|
{ |
|
struct request_queue *q = bio->bi_bdev->bd_disk->queue; |
|
bool same_page = false; |
|
|
|
if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_ZONE_APPEND)) |
|
return 0; |
|
|
|
if (WARN_ON_ONCE(!blk_queue_is_zoned(q))) |
|
return 0; |
|
|
|
return bio_add_hw_page(q, bio, page, len, offset, |
|
queue_max_zone_append_sectors(q), &same_page); |
|
} |
|
EXPORT_SYMBOL_GPL(bio_add_zone_append_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) { |
|
*same_page = false; |
|
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 void __bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter) |
|
{ |
|
WARN_ON_ONCE(bio->bi_max_vecs); |
|
|
|
bio->bi_vcnt = iter->nr_segs; |
|
bio->bi_io_vec = (struct bio_vec *)iter->bvec; |
|
bio->bi_iter.bi_bvec_done = iter->iov_offset; |
|
bio->bi_iter.bi_size = iter->count; |
|
bio_set_flag(bio, BIO_NO_PAGE_REF); |
|
bio_set_flag(bio, BIO_CLONED); |
|
} |
|
|
|
static int bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter) |
|
{ |
|
__bio_iov_bvec_set(bio, iter); |
|
iov_iter_advance(iter, iter->count); |
|
return 0; |
|
} |
|
|
|
static int bio_iov_bvec_set_append(struct bio *bio, struct iov_iter *iter) |
|
{ |
|
struct request_queue *q = bio->bi_bdev->bd_disk->queue; |
|
struct iov_iter i = *iter; |
|
|
|
iov_iter_truncate(&i, queue_max_zone_append_sectors(q) << 9); |
|
__bio_iov_bvec_set(bio, &i); |
|
iov_iter_advance(iter, i.count); |
|
return 0; |
|
} |
|
|
|
static void bio_put_pages(struct page **pages, size_t size, size_t off) |
|
{ |
|
size_t i, nr = DIV_ROUND_UP(size + (off & ~PAGE_MASK), PAGE_SIZE); |
|
|
|
for (i = 0; i < nr; i++) |
|
put_page(pages[i]); |
|
} |
|
|
|
#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))) { |
|
bio_put_pages(pages + i, left, offset); |
|
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_bdev->bd_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; |
|
int ret = 0; |
|
|
|
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) { |
|
bio_put_pages(pages + i, left, offset); |
|
ret = -EINVAL; |
|
break; |
|
} |
|
if (same_page) |
|
put_page(page); |
|
offset = 0; |
|
} |
|
|
|
iov_iter_advance(iter, size - left); |
|
return ret; |
|
} |
|
|
|
/** |
|
* 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. For bvec based iterators bio_iov_iter_get_pages() uses the provided |
|
* bvecs rather than copying them. Hence anyone issuing kiocb based IO needs |
|
* to ensure the bvecs and pages stay referenced until the submitted I/O is |
|
* completed by a call to ->ki_complete() or returns with an error other than |
|
* -EIOCBQUEUED. 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. |
|
* |
|
* It's intended for direct IO, so doesn't do PSI tracking, the caller is |
|
* responsible for setting BIO_WORKINGSET if necessary. |
|
*/ |
|
int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) |
|
{ |
|
int ret = 0; |
|
|
|
if (iov_iter_is_bvec(iter)) { |
|
if (bio_op(bio) == REQ_OP_ZONE_APPEND) |
|
return bio_iov_bvec_set_append(bio, iter); |
|
return bio_iov_bvec_set(bio, iter); |
|
} |
|
|
|
do { |
|
if (bio_op(bio) == REQ_OP_ZONE_APPEND) |
|
ret = __bio_iov_append_get_pages(bio, iter); |
|
else |
|
ret = __bio_iov_iter_get_pages(bio, iter); |
|
} while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); |
|
|
|
/* don't account direct I/O as memory stall */ |
|
bio_clear_flag(bio, BIO_WORKINGSET); |
|
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_bdev->bd_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) |
|
{ |
|
while (src_iter->bi_size && dst_iter->bi_size) { |
|
struct bio_vec src_bv = bio_iter_iovec(src, *src_iter); |
|
struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter); |
|
unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len); |
|
void *src_buf; |
|
|
|
src_buf = bvec_kmap_local(&src_bv); |
|
memcpy_to_bvec(&dst_bv, src_buf); |
|
kunmap_local(src_buf); |
|
|
|
bio_advance_iter_single(src, src_iter, bytes); |
|
bio_advance_iter_single(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); |
|
|
|
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. |
|
**/ |
|
void bio_endio(struct bio *bio) |
|
{ |
|
again: |
|
if (!bio_remaining_done(bio)) |
|
return; |
|
if (!bio_integrity_endio(bio)) |
|
return; |
|
|
|
if (bio->bi_bdev && bio_flagged(bio, BIO_TRACKED)) |
|
rq_qos_done_bio(bio->bi_bdev->bd_disk->queue, bio); |
|
|
|
if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) { |
|
trace_block_bio_complete(bio->bi_bdev->bd_disk->queue, bio); |
|
bio_clear_flag(bio, BIO_TRACE_COMPLETION); |
|
} |
|
|
|
/* |
|
* 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; |
|
} |
|
|
|
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 |
|
* |
|
* This function is typically used for bios that are cloned and submitted |
|
* to the underlying device in parts. |
|
*/ |
|
void bio_trim(struct bio *bio, sector_t offset, sector_t size) |
|
{ |
|
if (WARN_ON_ONCE(offset > BIO_MAX_SECTORS || size > BIO_MAX_SECTORS || |
|
offset + size > bio->bi_iter.bi_size)) |
|
return; |
|
|
|
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 + ARRAY_SIZE(bvec_slabs) - 1; |
|
|
|
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) |
|
{ |
|
bio_alloc_cache_destroy(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) |
|
{ |
|
bs->front_pad = front_pad; |
|
if (flags & BIOSET_NEED_BVECS) |
|
bs->back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); |
|
else |
|
bs->back_pad = 0; |
|
|
|
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(bs); |
|
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) { |
|
bs->rescue_workqueue = alloc_workqueue("bioset", |
|
WQ_MEM_RECLAIM, 0); |
|
if (!bs->rescue_workqueue) |
|
goto bad; |
|
} |
|
if (flags & BIOSET_PERCPU_CACHE) { |
|
bs->cache = alloc_percpu(struct bio_alloc_cache); |
|
if (!bs->cache) |
|
goto bad; |
|
cpuhp_state_add_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead); |
|
} |
|
|
|
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); |
|
|
|
/** |
|
* bio_alloc_kiocb - Allocate a bio from bio_set based on kiocb |
|
* @kiocb: kiocb describing the IO |
|
* @nr_vecs: number of iovecs to pre-allocate |
|
* @bs: bio_set to allocate from |
|
* |
|
* Description: |
|
* Like @bio_alloc_bioset, but pass in the kiocb. The kiocb is only |
|
* used to check if we should dip into the per-cpu bio_set allocation |
|
* cache. The allocation uses GFP_KERNEL internally. On return, the |
|
* bio is marked BIO_PERCPU_CACHEABLE, and the final put of the bio |
|
* MUST be done from process context, not hard/soft IRQ. |
|
* |
|
*/ |
|
struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs, |
|
struct bio_set *bs) |
|
{ |
|
struct bio_alloc_cache *cache; |
|
struct bio *bio; |
|
|
|
if (!(kiocb->ki_flags & IOCB_ALLOC_CACHE) || nr_vecs > BIO_INLINE_VECS) |
|
return bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs); |
|
|
|
cache = per_cpu_ptr(bs->cache, get_cpu()); |
|
bio = bio_list_pop(&cache->free_list); |
|
if (bio) { |
|
cache->nr--; |
|
put_cpu(); |
|
bio_init(bio, nr_vecs ? bio->bi_inline_vecs : NULL, nr_vecs); |
|
bio->bi_pool = bs; |
|
bio_set_flag(bio, BIO_PERCPU_CACHE); |
|
return bio; |
|
} |
|
put_cpu(); |
|
bio = bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs); |
|
bio_set_flag(bio, BIO_PERCPU_CACHE); |
|
return bio; |
|
} |
|
EXPORT_SYMBOL_GPL(bio_alloc_kiocb); |
|
|
|
static int __init init_bio(void) |
|
{ |
|
int i; |
|
|
|
bio_integrity_init(); |
|
|
|
for (i = 0; i < ARRAY_SIZE(bvec_slabs); i++) { |
|
struct biovec_slab *bvs = bvec_slabs + i; |
|
|
|
bvs->slab = kmem_cache_create(bvs->name, |
|
bvs->nr_vecs * sizeof(struct bio_vec), 0, |
|
SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); |
|
} |
|
|
|
cpuhp_setup_state_multi(CPUHP_BIO_DEAD, "block/bio:dead", NULL, |
|
bio_cpu_dead); |
|
|
|
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);
|
|
|