From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- block/bio.c | 1684 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1684 insertions(+) create mode 100644 block/bio.c (limited to 'block/bio.c') diff --git a/block/bio.c b/block/bio.c new file mode 100644 index 000000000..6d6e7b96b --- /dev/null +++ b/block/bio.c @@ -0,0 +1,1684 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2001 Jens Axboe + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include "blk.h" +#include "blk-rq-qos.h" + +/* + * Test patch to inline a certain number of bi_io_vec's inside the bio + * itself, to shrink a bio data allocation from two mempool calls to one + */ +#define BIO_INLINE_VECS 4 + +/* + * if you change this list, also change bvec_alloc or things will + * break badly! cannot be bigger than what you can fit into an + * unsigned short + */ +#define BV(x, n) { .nr_vecs = x, .name = "biovec-"#n } +static struct biovec_slab bvec_slabs[BVEC_POOL_NR] __read_mostly = { + BV(1, 1), BV(4, 4), BV(16, 16), BV(64, 64), BV(128, 128), BV(BIO_MAX_PAGES, max), +}; +#undef BV + +/* + * fs_bio_set is the bio_set containing bio and iovec memory pools used by + * IO code that does not need private memory pools. + */ +struct bio_set fs_bio_set; +EXPORT_SYMBOL(fs_bio_set); + +/* + * Our slab pool management + */ +struct bio_slab { + struct kmem_cache *slab; + unsigned int slab_ref; + unsigned int slab_size; + char name[8]; +}; +static DEFINE_MUTEX(bio_slab_lock); +static struct bio_slab *bio_slabs; +static unsigned int bio_slab_nr, bio_slab_max; + +static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size) +{ + unsigned int sz = sizeof(struct bio) + extra_size; + struct kmem_cache *slab = NULL; + struct bio_slab *bslab, *new_bio_slabs; + unsigned int new_bio_slab_max; + unsigned int i, entry = -1; + + mutex_lock(&bio_slab_lock); + + i = 0; + while (i < bio_slab_nr) { + bslab = &bio_slabs[i]; + + if (!bslab->slab && entry == -1) + entry = i; + else if (bslab->slab_size == sz) { + slab = bslab->slab; + bslab->slab_ref++; + break; + } + i++; + } + + if (slab) + goto out_unlock; + + if (bio_slab_nr == bio_slab_max && entry == -1) { + new_bio_slab_max = bio_slab_max << 1; + new_bio_slabs = krealloc(bio_slabs, + new_bio_slab_max * sizeof(struct bio_slab), + GFP_KERNEL); + if (!new_bio_slabs) + goto out_unlock; + bio_slab_max = new_bio_slab_max; + bio_slabs = new_bio_slabs; + } + if (entry == -1) + entry = bio_slab_nr++; + + bslab = &bio_slabs[entry]; + + snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry); + slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN, + SLAB_HWCACHE_ALIGN, NULL); + if (!slab) + goto out_unlock; + + bslab->slab = slab; + bslab->slab_ref = 1; + bslab->slab_size = sz; +out_unlock: + mutex_unlock(&bio_slab_lock); + return slab; +} + +static void bio_put_slab(struct bio_set *bs) +{ + struct bio_slab *bslab = NULL; + unsigned int i; + + mutex_lock(&bio_slab_lock); + + for (i = 0; i < bio_slab_nr; i++) { + if (bs->bio_slab == bio_slabs[i].slab) { + bslab = &bio_slabs[i]; + break; + } + } + + if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n")) + goto out; + + WARN_ON(!bslab->slab_ref); + + if (--bslab->slab_ref) + goto out; + + kmem_cache_destroy(bslab->slab); + bslab->slab = NULL; + +out: + mutex_unlock(&bio_slab_lock); +} + +unsigned int bvec_nr_vecs(unsigned short idx) +{ + return bvec_slabs[--idx].nr_vecs; +} + +void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx) +{ + if (!idx) + return; + idx--; + + BIO_BUG_ON(idx >= BVEC_POOL_NR); + + if (idx == BVEC_POOL_MAX) { + mempool_free(bv, pool); + } else { + struct biovec_slab *bvs = bvec_slabs + idx; + + kmem_cache_free(bvs->slab, bv); + } +} + +struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx, + mempool_t *pool) +{ + struct bio_vec *bvl; + + /* + * see comment near bvec_array define! + */ + switch (nr) { + case 1: + *idx = 0; + break; + case 2 ... 4: + *idx = 1; + break; + case 5 ... 16: + *idx = 2; + break; + case 17 ... 64: + *idx = 3; + break; + case 65 ... 128: + *idx = 4; + break; + case 129 ... BIO_MAX_PAGES: + *idx = 5; + break; + default: + return NULL; + } + + /* + * idx now points to the pool we want to allocate from. only the + * 1-vec entry pool is mempool backed. + */ + if (*idx == BVEC_POOL_MAX) { +fallback: + bvl = mempool_alloc(pool, gfp_mask); + } else { + struct biovec_slab *bvs = bvec_slabs + *idx; + gfp_t __gfp_mask = gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_IO); + + /* + * Make this allocation restricted and don't dump info on + * allocation failures, since we'll fallback to the mempool + * in case of failure. + */ + __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; + + /* + * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM + * is set, retry with the 1-entry mempool + */ + bvl = kmem_cache_alloc(bvs->slab, __gfp_mask); + if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) { + *idx = BVEC_POOL_MAX; + goto fallback; + } + } + + (*idx)++; + return bvl; +} + +void bio_uninit(struct bio *bio) +{ +#ifdef CONFIG_BLK_CGROUP + if (bio->bi_blkg) { + blkg_put(bio->bi_blkg); + bio->bi_blkg = NULL; + } +#endif + if (bio_integrity(bio)) + bio_integrity_free(bio); + + bio_crypt_free_ctx(bio); +} +EXPORT_SYMBOL(bio_uninit); + +static void bio_free(struct bio *bio) +{ + struct bio_set *bs = bio->bi_pool; + void *p; + + bio_uninit(bio); + + if (bs) { + bvec_free(&bs->bvec_pool, bio->bi_io_vec, BVEC_POOL_IDX(bio)); + + /* + * If we have front padding, adjust the bio pointer before freeing + */ + p = bio; + p -= bs->front_pad; + + mempool_free(p, &bs->bio_pool); + } else { + /* Bio was allocated by bio_kmalloc() */ + kfree(bio); + } +} + +/* + * Users of this function have their own bio allocation. Subsequently, + * they must remember to pair any call to bio_init() with bio_uninit() + * when IO has completed, or when the bio is released. + */ +void bio_init(struct bio *bio, struct bio_vec *table, + unsigned short max_vecs) +{ + memset(bio, 0, sizeof(*bio)); + atomic_set(&bio->__bi_remaining, 1); + atomic_set(&bio->__bi_cnt, 1); + + bio->bi_io_vec = table; + bio->bi_max_vecs = max_vecs; +} +EXPORT_SYMBOL(bio_init); + +/** + * bio_reset - reinitialize a bio + * @bio: bio to reset + * + * Description: + * After calling bio_reset(), @bio will be in the same state as a freshly + * allocated bio returned bio bio_alloc_bioset() - the only fields that are + * preserved are the ones that are initialized by bio_alloc_bioset(). See + * comment in struct bio. + */ +void bio_reset(struct bio *bio) +{ + unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS); + + bio_uninit(bio); + + memset(bio, 0, BIO_RESET_BYTES); + bio->bi_flags = flags; + atomic_set(&bio->__bi_remaining, 1); +} +EXPORT_SYMBOL(bio_reset); + +static struct bio *__bio_chain_endio(struct bio *bio) +{ + struct bio *parent = bio->bi_private; + + if (bio->bi_status && !parent->bi_status) + parent->bi_status = bio->bi_status; + bio_put(bio); + return parent; +} + +static void bio_chain_endio(struct bio *bio) +{ + bio_endio(__bio_chain_endio(bio)); +} + +/** + * bio_chain - chain bio completions + * @bio: the target bio + * @parent: the parent bio of @bio + * + * The caller won't have a bi_end_io called when @bio completes - instead, + * @parent's bi_end_io won't be called until both @parent and @bio have + * completed; the chained bio will also be freed when it completes. + * + * The caller must not set bi_private or bi_end_io in @bio. + */ +void bio_chain(struct bio *bio, struct bio *parent) +{ + BUG_ON(bio->bi_private || bio->bi_end_io); + + bio->bi_private = parent; + bio->bi_end_io = bio_chain_endio; + bio_inc_remaining(parent); +} +EXPORT_SYMBOL(bio_chain); + +static void bio_alloc_rescue(struct work_struct *work) +{ + struct bio_set *bs = container_of(work, struct bio_set, rescue_work); + struct bio *bio; + + while (1) { + spin_lock(&bs->rescue_lock); + bio = bio_list_pop(&bs->rescue_list); + spin_unlock(&bs->rescue_lock); + + if (!bio) + break; + + submit_bio_noacct(bio); + } +} + +static void punt_bios_to_rescuer(struct bio_set *bs) +{ + struct bio_list punt, nopunt; + struct bio *bio; + + if (WARN_ON_ONCE(!bs->rescue_workqueue)) + return; + /* + * In order to guarantee forward progress we must punt only bios that + * were allocated from this bio_set; otherwise, if there was a bio on + * there for a stacking driver higher up in the stack, processing it + * could require allocating bios from this bio_set, and doing that from + * our own rescuer would be bad. + * + * Since bio lists are singly linked, pop them all instead of trying to + * remove from the middle of the list: + */ + + bio_list_init(&punt); + bio_list_init(&nopunt); + + while ((bio = bio_list_pop(¤t->bio_list[0]))) + bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); + current->bio_list[0] = nopunt; + + bio_list_init(&nopunt); + while ((bio = bio_list_pop(¤t->bio_list[1]))) + bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); + current->bio_list[1] = nopunt; + + spin_lock(&bs->rescue_lock); + bio_list_merge(&bs->rescue_list, &punt); + spin_unlock(&bs->rescue_lock); + + queue_work(bs->rescue_workqueue, &bs->rescue_work); +} + +/** + * bio_alloc_bioset - allocate a bio for I/O + * @gfp_mask: the GFP_* mask given to the slab allocator + * @nr_iovecs: number of iovecs to pre-allocate + * @bs: the bio_set to allocate from. + * + * Description: + * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is + * backed by the @bs's mempool. + * + * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will + * always be able to 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 this pool. 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. Failure to do so can cause deadlocks under memory pressure. + * + * 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. + * + * 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 + * thread. + * + * However, we do not guarantee forward progress for allocations from other + * mempools. Doing multiple allocations from the same mempool under + * submit_bio_noacct() should be avoided - instead, use bio_set's front_pad + * for per bio allocations. + * + * RETURNS: + * Pointer to new bio on success, NULL on failure. + */ +struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned int nr_iovecs, + struct bio_set *bs) +{ + gfp_t saved_gfp = gfp_mask; + unsigned front_pad; + unsigned inline_vecs; + struct bio_vec *bvl = NULL; + struct bio *bio; + void *p; + + if (!bs) { + if (nr_iovecs > UIO_MAXIOV) + return NULL; + + p = kmalloc(struct_size(bio, bi_inline_vecs, nr_iovecs), gfp_mask); + front_pad = 0; + inline_vecs = nr_iovecs; + } else { + /* should not use nobvec bioset for nr_iovecs > 0 */ + 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 mempool's + * reserve. + * + * We solve this, and guarantee forward progress, with a rescuer + * workqueue per bio_set. If we go to allocate and there are + * bios on current->bio_list, we first try the allocation + * without __GFP_DIRECT_RECLAIM; if that fails, we punt those + * bios we would be blocking to the rescuer workqueue before + * we retry with the original gfp_flags. + */ + + if (current->bio_list && + (!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); + } + + front_pad = bs->front_pad; + inline_vecs = BIO_INLINE_VECS; + } + + if (unlikely(!p)) + return NULL; + + bio = p + front_pad; + bio_init(bio, NULL, 0); + + if (nr_iovecs > inline_vecs) { + unsigned long idx = 0; + + bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, &bs->bvec_pool); + if (!bvl && gfp_mask != saved_gfp) { + punt_bios_to_rescuer(bs); + gfp_mask = saved_gfp; + bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, &bs->bvec_pool); + } + + if (unlikely(!bvl)) + goto err_free; + + bio->bi_flags |= idx << BVEC_POOL_OFFSET; + } else if (nr_iovecs) { + bvl = bio->bi_inline_vecs; + } + + bio->bi_pool = bs; + bio->bi_max_vecs = nr_iovecs; + bio->bi_io_vec = bvl; + return bio; + +err_free: + mempool_free(p, &bs->bio_pool); + return NULL; +} +EXPORT_SYMBOL(bio_alloc_bioset); + +void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start) +{ + unsigned long flags; + struct bio_vec bv; + struct bvec_iter iter; + + __bio_for_each_segment(bv, bio, iter, start) { + char *data = bvec_kmap_irq(&bv, &flags); + memset(data, 0, bv.bv_len); + flush_dcache_page(bv.bv_page); + bvec_kunmap_irq(data, &flags); + } +} +EXPORT_SYMBOL(zero_fill_bio_iter); + +/** + * bio_truncate - truncate the bio to small size of @new_size + * @bio: the bio to be truncated + * @new_size: new size for truncating the bio + * + * Description: + * Truncate the bio to new size of @new_size. If bio_op(bio) is + * REQ_OP_READ, zero the truncated part. This function should only + * be used for handling corner cases, such as bio eod. + */ +void bio_truncate(struct bio *bio, unsigned new_size) +{ + struct bio_vec bv; + struct bvec_iter iter; + unsigned int done = 0; + bool truncated = false; + + if (new_size >= bio->bi_iter.bi_size) + return; + + if (bio_op(bio) != REQ_OP_READ) + goto exit; + + bio_for_each_segment(bv, bio, iter) { + if (done + bv.bv_len > new_size) { + unsigned offset; + + if (!truncated) + offset = new_size - done; + else + offset = 0; + zero_user(bv.bv_page, bv.bv_offset + offset, + bv.bv_len - offset); + truncated = true; + } + done += bv.bv_len; + } + + exit: + /* + * Don't touch bvec table here and make it really immutable, since + * fs bio user has to retrieve all pages via bio_for_each_segment_all + * in its .end_bio() callback. + * + * It is enough to truncate bio by updating .bi_size since we can make + * correct bvec with the updated .bi_size for drivers. + */ + bio->bi_iter.bi_size = new_size; +} + +/** + * guard_bio_eod - truncate a BIO to fit the block device + * @bio: bio to truncate + * + * This allows us to do IO even on the odd last sectors of a device, even if the + * block size is some multiple of the physical sector size. + * + * We'll just truncate the bio to the size of the device, and clear the end of + * the buffer head manually. Truly out-of-range accesses will turn into actual + * I/O errors, this only handles the "we need to be able to do I/O at the final + * sector" case. + */ +void guard_bio_eod(struct bio *bio) +{ + sector_t maxsector; + struct hd_struct *part; + + rcu_read_lock(); + part = __disk_get_part(bio->bi_disk, bio->bi_partno); + if (part) + maxsector = part_nr_sects_read(part); + else + maxsector = get_capacity(bio->bi_disk); + rcu_read_unlock(); + + if (!maxsector) + return; + + /* + * If the *whole* IO is past the end of the device, + * let it through, and the IO layer will turn it into + * an EIO. + */ + if (unlikely(bio->bi_iter.bi_sector >= maxsector)) + return; + + maxsector -= bio->bi_iter.bi_sector; + if (likely((bio->bi_iter.bi_size >> 9) <= maxsector)) + return; + + bio_truncate(bio, maxsector << 9); +} + +/** + * bio_put - release a reference to a bio + * @bio: bio to release reference to + * + * Description: + * Put a reference to a &struct bio, either one you have gotten with + * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it. + **/ +void bio_put(struct bio *bio) +{ + if (!bio_flagged(bio, BIO_REFFED)) + bio_free(bio); + else { + BIO_BUG_ON(!atomic_read(&bio->__bi_cnt)); + + /* + * last put frees it + */ + if (atomic_dec_and_test(&bio->__bi_cnt)) + bio_free(bio); + } +} +EXPORT_SYMBOL(bio_put); + +/** + * __bio_clone_fast - clone a bio that shares the original bio's biovec + * @bio: destination bio + * @bio_src: bio to clone + * + * Clone a &bio. Caller will own the returned bio, but not + * the actual data it points to. Reference count of returned + * bio will be one. + * + * Caller must ensure that @bio_src is not freed before @bio. + */ +void __bio_clone_fast(struct bio *bio, struct bio *bio_src) +{ + BUG_ON(bio->bi_pool && BVEC_POOL_IDX(bio)); + + /* + * most users will be overriding ->bi_disk with a new target, + * so we don't set nor calculate new physical/hw segment counts here + */ + bio->bi_disk = bio_src->bi_disk; + bio->bi_partno = bio_src->bi_partno; + bio_set_flag(bio, BIO_CLONED); + if (bio_flagged(bio_src, BIO_THROTTLED)) + bio_set_flag(bio, BIO_THROTTLED); + bio->bi_opf = bio_src->bi_opf; + bio->bi_ioprio = bio_src->bi_ioprio; + bio->bi_write_hint = bio_src->bi_write_hint; + bio->bi_iter = bio_src->bi_iter; + bio->bi_io_vec = bio_src->bi_io_vec; + + bio_clone_blkg_association(bio, bio_src); + blkcg_bio_issue_init(bio); +} +EXPORT_SYMBOL(__bio_clone_fast); + +/** + * bio_clone_fast - clone a bio that shares the original bio's biovec + * @bio: bio to clone + * @gfp_mask: allocation priority + * @bs: bio_set to allocate from + * + * Like __bio_clone_fast, only also allocates the returned bio + */ +struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs) +{ + struct bio *b; + + b = bio_alloc_bioset(gfp_mask, 0, bs); + if (!b) + return NULL; + + __bio_clone_fast(b, bio); + + 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 disk_name(bio->bi_disk, bio->bi_partno, buf); +} +EXPORT_SYMBOL(bio_devname); + +static inline bool page_is_mergeable(const struct bio_vec *bv, + struct page *page, unsigned int len, unsigned int off, + bool *same_page) +{ + size_t bv_end = bv->bv_offset + bv->bv_len; + phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1; + phys_addr_t page_addr = page_to_phys(page); + + if (vec_end_addr + 1 != page_addr + off) + return false; + if (xen_domain() && !xen_biovec_phys_mergeable(bv, page)) + return false; + + *same_page = ((vec_end_addr & PAGE_MASK) == page_addr); + if (*same_page) + return true; + return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE); +} + +/* + * Try to merge a page into a segment, while obeying the hardware segment + * size limit. This is not for normal read/write bios, but for passthrough + * or Zone Append operations that we can't split. + */ +static bool bio_try_merge_hw_seg(struct request_queue *q, struct bio *bio, + struct page *page, unsigned len, + unsigned offset, bool *same_page) +{ + struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; + unsigned long mask = queue_segment_boundary(q); + phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset; + phys_addr_t addr2 = page_to_phys(page) + offset + len - 1; + + if ((addr1 | mask) != (addr2 | mask)) + return false; + if (bv->bv_len + len > queue_max_segment_size(q)) + return false; + return __bio_try_merge_page(bio, page, len, offset, same_page); +} + +/** + * bio_add_hw_page - attempt to add a page to a bio with hw constraints + * @q: the target queue + * @bio: destination bio + * @page: page to add + * @len: vec entry length + * @offset: vec entry offset + * @max_sectors: maximum number of sectors that can be added + * @same_page: return if the segment has been merged inside the same page + * + * Add a page to a bio while respecting the hardware max_sectors, max_segment + * and gap limitations. + */ +int bio_add_hw_page(struct request_queue *q, struct bio *bio, + struct page *page, unsigned int len, unsigned int offset, + unsigned int max_sectors, bool *same_page) +{ + struct bio_vec *bvec; + + if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) + return 0; + + if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors) + return 0; + + if (bio->bi_vcnt > 0) { + if (bio_try_merge_hw_seg(q, bio, page, len, offset, same_page)) + return len; + + /* + * If the queue doesn't support SG gaps and adding this segment + * would create a gap, disallow it. + */ + bvec = &bio->bi_io_vec[bio->bi_vcnt - 1]; + if (bvec_gap_to_prev(q, bvec, offset)) + return 0; + } + + if (bio_full(bio, len)) + return 0; + + if (bio->bi_vcnt >= queue_max_segments(q)) + return 0; + + bvec = &bio->bi_io_vec[bio->bi_vcnt]; + bvec->bv_page = page; + bvec->bv_len = len; + bvec->bv_offset = offset; + bio->bi_vcnt++; + bio->bi_iter.bi_size += len; + return len; +} + +/** + * bio_add_pc_page - attempt to add page to passthrough bio + * @q: the target queue + * @bio: destination bio + * @page: page to add + * @len: vec entry length + * @offset: vec entry offset + * + * Attempt to add a page to the bio_vec maplist. This can fail for a + * number of reasons, such as the bio being full or target block device + * limitations. The target block device must allow bio's up to PAGE_SIZE, + * so it is always possible to add a single page to an empty bio. + * + * This should only be used by passthrough bios. + */ +int bio_add_pc_page(struct request_queue *q, struct bio *bio, + struct page *page, unsigned int len, unsigned int offset) +{ + bool same_page = false; + return bio_add_hw_page(q, bio, page, len, offset, + queue_max_hw_sectors(q), &same_page); +} +EXPORT_SYMBOL(bio_add_pc_page); + +/** + * __bio_try_merge_page - try appending data to an existing bvec. + * @bio: destination bio + * @page: start page to add + * @len: length of the data to add + * @off: offset of the data relative to @page + * @same_page: return if the segment has been merged inside the same page + * + * Try to add the data at @page + @off to the last bvec of @bio. This is a + * useful optimisation for file systems with a block size smaller than the + * page size. + * + * Warn if (@len, @off) crosses pages in case that @same_page is true. + * + * Return %true on success or %false on failure. + */ +bool __bio_try_merge_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int off, bool *same_page) +{ + if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) + return false; + + if (bio->bi_vcnt > 0) { + struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; + + if (page_is_mergeable(bv, page, len, off, same_page)) { + if (bio->bi_iter.bi_size > UINT_MAX - len) { + *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 int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter) +{ + const struct bio_vec *bv = iter->bvec; + unsigned int len; + size_t size; + + if (WARN_ON_ONCE(iter->iov_offset > bv->bv_len)) + return -EINVAL; + + len = min_t(size_t, bv->bv_len - iter->iov_offset, iter->count); + size = bio_add_page(bio, bv->bv_page, len, + bv->bv_offset + iter->iov_offset); + if (unlikely(size != len)) + return -EINVAL; + iov_iter_advance(iter, size); + return 0; +} + +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_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; + + /* + * 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. If we're adding kernel pages, and the caller told us it's safe to + * do so, we just have to add the pages to the bio directly. We don't grab an + * extra reference to those pages (the user should already have that), and we + * don't put the page on IO completion. The caller needs to check if the bio is + * flagged BIO_NO_PAGE_REF on IO completion. If it isn't, then pages should be + * released. + * + * The function tries, but does not guarantee, to pin as many pages as + * fit into the bio, or are requested in @iter, whatever is smaller. If + * MM encounters an error pinning the requested pages, it stops. Error + * is returned only if 0 pages could be pinned. + */ +int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) +{ + const bool is_bvec = iov_iter_is_bvec(iter); + int ret; + + if (WARN_ON_ONCE(bio->bi_vcnt)) + return -EINVAL; + + do { + if (bio_op(bio) == REQ_OP_ZONE_APPEND) { + if (WARN_ON_ONCE(is_bvec)) + return -EINVAL; + ret = __bio_iov_append_get_pages(bio, iter); + } else { + if (is_bvec) + ret = __bio_iov_bvec_add_pages(bio, iter); + else + ret = __bio_iov_iter_get_pages(bio, iter); + } + } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); + + if (is_bvec) + bio_set_flag(bio, BIO_NO_PAGE_REF); + return bio->bi_vcnt ? 0 : ret; +} +EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages); + +static void submit_bio_wait_endio(struct bio *bio) +{ + complete(bio->bi_private); +} + +/** + * submit_bio_wait - submit a bio, and wait until it completes + * @bio: The &struct bio which describes the I/O + * + * Simple wrapper around submit_bio(). Returns 0 on success, or the error from + * bio_endio() on failure. + * + * WARNING: Unlike to how submit_bio() is usually used, this function does not + * result in bio reference to be consumed. The caller must drop the reference + * on his own. + */ +int submit_bio_wait(struct bio *bio) +{ + DECLARE_COMPLETION_ONSTACK_MAP(done, bio->bi_disk->lockdep_map); + unsigned long hang_check; + + bio->bi_private = &done; + bio->bi_end_io = submit_bio_wait_endio; + bio->bi_opf |= REQ_SYNC; + submit_bio(bio); + + /* Prevent hang_check timer from firing at us during very long I/O */ + hang_check = sysctl_hung_task_timeout_secs; + if (hang_check) + while (!wait_for_completion_io_timeout(&done, + hang_check * (HZ/2))) + ; + else + wait_for_completion_io(&done); + + return blk_status_to_errno(bio->bi_status); +} +EXPORT_SYMBOL(submit_bio_wait); + +/** + * bio_advance - increment/complete a bio by some number of bytes + * @bio: bio to advance + * @bytes: number of bytes to complete + * + * This updates bi_sector, bi_size and bi_idx; if the number of bytes to + * complete doesn't align with a bvec boundary, then bv_len and bv_offset will + * be updated on the last bvec as well. + * + * @bio will then represent the remaining, uncompleted portion of the io. + */ +void bio_advance(struct bio *bio, unsigned bytes) +{ + if (bio_integrity(bio)) + bio_integrity_advance(bio, bytes); + + bio_crypt_advance(bio, bytes); + bio_advance_iter(bio, &bio->bi_iter, bytes); +} +EXPORT_SYMBOL(bio_advance); + +void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter, + struct bio *src, struct bvec_iter *src_iter) +{ + struct bio_vec src_bv, dst_bv; + void *src_p, *dst_p; + unsigned bytes; + + while (src_iter->bi_size && dst_iter->bi_size) { + src_bv = bio_iter_iovec(src, *src_iter); + dst_bv = bio_iter_iovec(dst, *dst_iter); + + bytes = min(src_bv.bv_len, dst_bv.bv_len); + + src_p = kmap_atomic(src_bv.bv_page); + dst_p = kmap_atomic(dst_bv.bv_page); + + memcpy(dst_p + dst_bv.bv_offset, + src_p + src_bv.bv_offset, + bytes); + + kunmap_atomic(dst_p); + kunmap_atomic(src_p); + + flush_dcache_page(dst_bv.bv_page); + + bio_advance_iter(src, src_iter, bytes); + bio_advance_iter(dst, dst_iter, bytes); + } +} +EXPORT_SYMBOL(bio_copy_data_iter); + +/** + * bio_copy_data - copy contents of data buffers from one bio to another + * @src: source bio + * @dst: destination bio + * + * Stops when it reaches the end of either @src or @dst - that is, copies + * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). + */ +void bio_copy_data(struct bio *dst, struct bio *src) +{ + struct bvec_iter src_iter = src->bi_iter; + struct bvec_iter dst_iter = dst->bi_iter; + + bio_copy_data_iter(dst, &dst_iter, src, &src_iter); +} +EXPORT_SYMBOL(bio_copy_data); + +/** + * bio_list_copy_data - copy contents of data buffers from one chain of bios to + * another + * @src: source bio list + * @dst: destination bio list + * + * Stops when it reaches the end of either the @src list or @dst list - that is, + * copies min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of + * bios). + */ +void bio_list_copy_data(struct bio *dst, struct bio *src) +{ + struct bvec_iter src_iter = src->bi_iter; + struct bvec_iter dst_iter = dst->bi_iter; + + while (1) { + if (!src_iter.bi_size) { + src = src->bi_next; + if (!src) + break; + + src_iter = src->bi_iter; + } + + if (!dst_iter.bi_size) { + dst = dst->bi_next; + if (!dst) + break; + + dst_iter = dst->bi_iter; + } + + bio_copy_data_iter(dst, &dst_iter, src, &src_iter); + } +} +EXPORT_SYMBOL(bio_list_copy_data); + +void bio_free_pages(struct bio *bio) +{ + struct bio_vec *bvec; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bvec, bio, iter_all) + __free_page(bvec->bv_page); +} +EXPORT_SYMBOL(bio_free_pages); + +/* + * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions + * for performing direct-IO in BIOs. + * + * The problem is that we cannot run set_page_dirty() from interrupt context + * because the required locks are not interrupt-safe. So what we can do is to + * mark the pages dirty _before_ performing IO. And in interrupt context, + * check that the pages are still dirty. If so, fine. If not, redirty them + * in process context. + * + * We special-case compound pages here: normally this means reads into hugetlb + * pages. The logic in here doesn't really work right for compound pages + * because the VM does not uniformly chase down the head page in all cases. + * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't + * handle them at all. So we skip compound pages here at an early stage. + * + * Note that this code is very hard to test under normal circumstances because + * direct-io pins the pages with get_user_pages(). This makes + * is_page_cache_freeable return false, and the VM will not clean the pages. + * But other code (eg, flusher threads) could clean the pages if they are mapped + * pagecache. + * + * Simply disabling the call to bio_set_pages_dirty() is a good way to test the + * deferred bio dirtying paths. + */ + +/* + * bio_set_pages_dirty() will mark all the bio's pages as dirty. + */ +void bio_set_pages_dirty(struct bio *bio) +{ + struct bio_vec *bvec; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bvec, bio, iter_all) { + if (!PageCompound(bvec->bv_page)) + set_page_dirty_lock(bvec->bv_page); + } +} + +/* + * bio_check_pages_dirty() will check that all the BIO's pages are still dirty. + * If they are, then fine. If, however, some pages are clean then they must + * have been written out during the direct-IO read. So we take another ref on + * the BIO and re-dirty the pages in process context. + * + * It is expected that bio_check_pages_dirty() will wholly own the BIO from + * here on. It will run one put_page() against each page and will run one + * bio_put() against the BIO. + */ + +static void bio_dirty_fn(struct work_struct *work); + +static DECLARE_WORK(bio_dirty_work, bio_dirty_fn); +static DEFINE_SPINLOCK(bio_dirty_lock); +static struct bio *bio_dirty_list; + +/* + * This runs in process context + */ +static void bio_dirty_fn(struct work_struct *work) +{ + struct bio *bio, *next; + + spin_lock_irq(&bio_dirty_lock); + next = bio_dirty_list; + bio_dirty_list = NULL; + spin_unlock_irq(&bio_dirty_lock); + + while ((bio = next) != NULL) { + next = bio->bi_private; + + bio_release_pages(bio, true); + bio_put(bio); + } +} + +void bio_check_pages_dirty(struct bio *bio) +{ + struct bio_vec *bvec; + unsigned long flags; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bvec, bio, iter_all) { + if (!PageDirty(bvec->bv_page) && !PageCompound(bvec->bv_page)) + goto defer; + } + + bio_release_pages(bio, false); + bio_put(bio); + return; +defer: + spin_lock_irqsave(&bio_dirty_lock, flags); + bio->bi_private = bio_dirty_list; + bio_dirty_list = bio; + spin_unlock_irqrestore(&bio_dirty_lock, flags); + schedule_work(&bio_dirty_work); +} + +static inline bool bio_remaining_done(struct bio *bio) +{ + /* + * If we're not chaining, then ->__bi_remaining is always 1 and + * we always end io on the first invocation. + */ + if (!bio_flagged(bio, BIO_CHAIN)) + return true; + + BUG_ON(atomic_read(&bio->__bi_remaining) <= 0); + + if (atomic_dec_and_test(&bio->__bi_remaining)) { + bio_clear_flag(bio, BIO_CHAIN); + return true; + } + + return false; +} + +/** + * bio_endio - end I/O on a bio + * @bio: bio + * + * Description: + * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred + * way to end I/O on a bio. No one should call bi_end_io() directly on a + * bio unless they own it and thus know that it has an end_io function. + * + * bio_endio() can be called several times on a bio that has been chained + * using bio_chain(). The ->bi_end_io() function will only be called the + * last time. At this point the BLK_TA_COMPLETE tracing event will be + * generated if BIO_TRACE_COMPLETION is set. + **/ +void bio_endio(struct bio *bio) +{ +again: + if (!bio_remaining_done(bio)) + return; + if (!bio_integrity_endio(bio)) + return; + + if (bio->bi_disk) + rq_qos_done_bio(bio->bi_disk->queue, bio); + + /* + * Need to have a real endio function for chained bios, otherwise + * various corner cases will break (like stacking block devices that + * save/restore bi_end_io) - however, we want to avoid unbounded + * recursion and blowing the stack. Tail call optimization would + * handle this, but compiling with frame pointers also disables + * gcc's sibling call optimization. + */ + if (bio->bi_end_io == bio_chain_endio) { + bio = __bio_chain_endio(bio); + goto again; + } + + if (bio->bi_disk && bio_flagged(bio, BIO_TRACE_COMPLETION)) { + trace_block_bio_complete(bio->bi_disk->queue, bio); + bio_clear_flag(bio, BIO_TRACE_COMPLETION); + } + + blk_throtl_bio_endio(bio); + /* release cgroup info */ + bio_uninit(bio); + if (bio->bi_end_io) + bio->bi_end_io(bio); +} +EXPORT_SYMBOL(bio_endio); + +/** + * bio_split - split a bio + * @bio: bio to split + * @sectors: number of sectors to split from the front of @bio + * @gfp: gfp mask + * @bs: bio set to allocate from + * + * Allocates and returns a new bio which represents @sectors from the start of + * @bio, and updates @bio to represent the remaining sectors. + * + * Unless this is a discard request the newly allocated bio will point + * to @bio's bi_io_vec. It is the caller's responsibility to ensure that + * neither @bio nor @bs are freed before the split bio. + */ +struct bio *bio_split(struct bio *bio, int sectors, + gfp_t gfp, struct bio_set *bs) +{ + struct bio *split; + + BUG_ON(sectors <= 0); + BUG_ON(sectors >= bio_sectors(bio)); + + /* Zone append commands cannot be split */ + if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND)) + return NULL; + + split = bio_clone_fast(bio, gfp, bs); + if (!split) + return NULL; + + split->bi_iter.bi_size = sectors << 9; + + if (bio_integrity(split)) + bio_integrity_trim(split); + + bio_advance(bio, split->bi_iter.bi_size); + + if (bio_flagged(bio, BIO_TRACE_COMPLETION)) + bio_set_flag(split, BIO_TRACE_COMPLETION); + + return split; +} +EXPORT_SYMBOL(bio_split); + +/** + * bio_trim - trim a bio + * @bio: bio to trim + * @offset: number of sectors to trim from the front of @bio + * @size: size we want to trim @bio to, in sectors + */ +void bio_trim(struct bio *bio, int offset, int size) +{ + /* 'bio' is a cloned bio which we need to trim to match + * the given offset and size. + */ + + size <<= 9; + if (offset == 0 && size == bio->bi_iter.bi_size) + return; + + bio_advance(bio, offset << 9); + bio->bi_iter.bi_size = size; + + if (bio_integrity(bio)) + bio_integrity_trim(bio); + +} +EXPORT_SYMBOL_GPL(bio_trim); + +/* + * create memory pools for biovec's in a bio_set. + * use the global biovec slabs created for general use. + */ +int biovec_init_pool(mempool_t *pool, int pool_entries) +{ + struct biovec_slab *bp = bvec_slabs + BVEC_POOL_MAX; + + return mempool_init_slab_pool(pool, pool_entries, bp->slab); +} + +/* + * bioset_exit - exit a bioset initialized with bioset_init() + * + * May be called on a zeroed but uninitialized bioset (i.e. allocated with + * kzalloc()). + */ +void bioset_exit(struct bio_set *bs) +{ + if (bs->rescue_workqueue) + destroy_workqueue(bs->rescue_workqueue); + bs->rescue_workqueue = NULL; + + mempool_exit(&bs->bio_pool); + mempool_exit(&bs->bvec_pool); + + bioset_integrity_free(bs); + if (bs->bio_slab) + bio_put_slab(bs); + bs->bio_slab = NULL; +} +EXPORT_SYMBOL(bioset_exit); + +/** + * bioset_init - Initialize a bio_set + * @bs: pool to initialize + * @pool_size: Number of bio and bio_vecs to cache in the mempool + * @front_pad: Number of bytes to allocate in front of the returned bio + * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS + * and %BIOSET_NEED_RESCUER + * + * Description: + * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller + * to ask for a number of bytes to be allocated in front of the bio. + * Front pad allocation is useful for embedding the bio inside + * another structure, to avoid allocating extra data to go with the bio. + * Note that the bio must be embedded at the END of that structure always, + * or things will break badly. + * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated + * for allocating iovecs. This pool is not needed e.g. for bio_clone_fast(). + * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used to + * dispatch queued requests when the mempool runs out of space. + * + */ +int bioset_init(struct bio_set *bs, + unsigned int pool_size, + unsigned int front_pad, + int flags) +{ + unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); + + bs->front_pad = front_pad; + + spin_lock_init(&bs->rescue_lock); + bio_list_init(&bs->rescue_list); + INIT_WORK(&bs->rescue_work, bio_alloc_rescue); + + bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad); + if (!bs->bio_slab) + return -ENOMEM; + + if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab)) + goto bad; + + if ((flags & BIOSET_NEED_BVECS) && + biovec_init_pool(&bs->bvec_pool, pool_size)) + goto bad; + + if (!(flags & BIOSET_NEED_RESCUER)) + return 0; + + bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0); + if (!bs->rescue_workqueue) + goto bad; + + return 0; +bad: + bioset_exit(bs); + return -ENOMEM; +} +EXPORT_SYMBOL(bioset_init); + +/* + * Initialize and setup a new bio_set, based on the settings from + * another bio_set. + */ +int bioset_init_from_src(struct bio_set *bs, struct bio_set *src) +{ + int flags; + + flags = 0; + if (src->bvec_pool.min_nr) + flags |= BIOSET_NEED_BVECS; + if (src->rescue_workqueue) + flags |= BIOSET_NEED_RESCUER; + + return bioset_init(bs, src->bio_pool.min_nr, src->front_pad, flags); +} +EXPORT_SYMBOL(bioset_init_from_src); + +static void __init biovec_init_slabs(void) +{ + int i; + + for (i = 0; i < BVEC_POOL_NR; i++) { + int size; + struct biovec_slab *bvs = bvec_slabs + i; + + if (bvs->nr_vecs <= BIO_INLINE_VECS) { + bvs->slab = NULL; + continue; + } + + size = bvs->nr_vecs * sizeof(struct bio_vec); + bvs->slab = kmem_cache_create(bvs->name, size, 0, + SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); + } +} + +static int __init init_bio(void) +{ + bio_slab_max = 2; + bio_slab_nr = 0; + bio_slabs = kcalloc(bio_slab_max, sizeof(struct bio_slab), + GFP_KERNEL); + + BUILD_BUG_ON(BIO_FLAG_LAST > BVEC_POOL_OFFSET); + + if (!bio_slabs) + panic("bio: can't allocate bios\n"); + + bio_integrity_init(); + biovec_init_slabs(); + + if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS)) + panic("bio: can't allocate bios\n"); + + if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE)) + panic("bio: can't create integrity pool\n"); + + return 0; +} +subsys_initcall(init_bio); -- cgit v1.2.3