| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Christoph Hellwig | 2835 | 30.10% | 17 | 9.60% |
| Benjamin LaHaise | 2349 | 24.94% | 22 | 12.43% |
| Kent Overstreet | 1418 | 15.05% | 23 | 12.99% |
| Al Viro | 703 | 7.46% | 25 | 14.12% |
| Suparna Bhattacharya | 396 | 4.20% | 1 | 0.56% |
| Gu Zheng | 337 | 3.58% | 7 | 3.95% |
| Linus Torvalds | 225 | 2.39% | 6 | 3.39% |
| Oleg Nesterov | 116 | 1.23% | 3 | 1.69% |
| Deepa Dinamani | 115 | 1.22% | 1 | 0.56% |
| Jens Axboe | 115 | 1.22% | 3 | 1.69% |
| Pavel Emelyanov | 110 | 1.17% | 1 | 0.56% |
| Zach Brown | 101 | 1.07% | 3 | 1.69% |
| Tejun Heo | 78 | 0.83% | 7 | 3.95% |
| Adam Manzanares | 59 | 0.63% | 3 | 1.69% |
| Jeff Moyer | 53 | 0.56% | 4 | 2.26% |
| Heiko Carstens | 38 | 0.40% | 1 | 0.56% |
| Anatol Pomozov | 37 | 0.39% | 1 | 0.56% |
| Badari Pulavarty | 35 | 0.37% | 2 | 1.13% |
| Davide Libenzi | 34 | 0.36% | 3 | 1.69% |
| Jann Horn | 24 | 0.25% | 1 | 0.56% |
| Andrew Morton | 22 | 0.23% | 5 | 2.82% |
| Mauricio Faria de Oliveira | 21 | 0.22% | 1 | 0.56% |
| Fam Zheng | 21 | 0.22% | 1 | 0.56% |
| Michal Hocko | 20 | 0.21% | 1 | 0.56% |
| Shaohua Li | 12 | 0.13% | 1 | 0.56% |
| Rasmus Villemoes | 12 | 0.13% | 1 | 0.56% |
| David Shaohua Li | 11 | 0.12% | 1 | 0.56% |
| Jérôme Glisse | 11 | 0.12% | 1 | 0.56% |
| James Morris | 10 | 0.11% | 1 | 0.56% |
| Ken Chen | 10 | 0.11% | 1 | 0.56% |
| Jan Kara | 8 | 0.08% | 1 | 0.56% |
| Kenneth W. Chen | 8 | 0.08% | 1 | 0.56% |
| Sasha Levin | 8 | 0.08% | 1 | 0.56% |
| Gleb Natapov | 6 | 0.06% | 1 | 0.56% |
| Christoph Lameter | 6 | 0.06% | 2 | 1.13% |
| Dan Carpenter | 5 | 0.05% | 1 | 0.56% |
| H Hartley Sweeten | 5 | 0.05% | 1 | 0.56% |
| Dave Chinner | 4 | 0.04% | 1 | 0.56% |
| Darrick J. Wong | 4 | 0.04% | 1 | 0.56% |
| Quentin Barnes | 4 | 0.04% | 1 | 0.56% |
| Michael S. Tsirkin | 3 | 0.03% | 1 | 0.56% |
| Goldwyn Rodrigues | 3 | 0.03% | 1 | 0.56% |
| John Myers | 3 | 0.03% | 1 | 0.56% |
| Adrian Bunk | 3 | 0.03% | 2 | 1.13% |
| Ingo Molnar | 3 | 0.03% | 2 | 1.13% |
| Michel Lespinasse | 3 | 0.03% | 2 | 1.13% |
| Miklos Szeredi | 3 | 0.03% | 1 | 0.56% |
| Arnd Bergmann | 3 | 0.03% | 1 | 0.56% |
| Mike Rapoport | 2 | 0.02% | 1 | 0.56% |
| Kinglong Mee | 2 | 0.02% | 1 | 0.56% |
| Oliver Neukum | 1 | 0.01% | 1 | 0.56% |
| Tang Chen | 1 | 0.01% | 1 | 0.56% |
| Paul Gortmaker | 1 | 0.01% | 1 | 0.56% |
| Satoru Takeuchi | 1 | 0.01% | 1 | 0.56% |
| Robert P. J. Day | 1 | 0.01% | 1 | 0.56% |
| Total | 9419 | 177 |
/* * An async IO implementation for Linux * Written by Benjamin LaHaise <bcrl@kvack.org> * * Implements an efficient asynchronous io interface. * * Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved. * Copyright 2018 Christoph Hellwig. * * See ../COPYING for licensing terms. */ #define pr_fmt(fmt) "%s: " fmt, __func__ #include <linux/kernel.h> #include <linux/init.h> #include <linux/errno.h> #include <linux/time.h> #include <linux/aio_abi.h> #include <linux/export.h> #include <linux/syscalls.h> #include <linux/backing-dev.h> #include <linux/refcount.h> #include <linux/uio.h> #include <linux/sched/signal.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/mm.h> #include <linux/mman.h> #include <linux/mmu_context.h> #include <linux/percpu.h> #include <linux/slab.h> #include <linux/timer.h> #include <linux/aio.h> #include <linux/highmem.h> #include <linux/workqueue.h> #include <linux/security.h> #include <linux/eventfd.h> #include <linux/blkdev.h> #include <linux/compat.h> #include <linux/migrate.h> #include <linux/ramfs.h> #include <linux/percpu-refcount.h> #include <linux/mount.h> #include <asm/kmap_types.h> #include <linux/uaccess.h> #include "internal.h" #define KIOCB_KEY 0 #define AIO_RING_MAGIC 0xa10a10a1 #define AIO_RING_COMPAT_FEATURES 1 #define AIO_RING_INCOMPAT_FEATURES 0 struct aio_ring { unsigned id; /* kernel internal index number */ unsigned nr; /* number of io_events */ unsigned head; /* Written to by userland or under ring_lock * mutex by aio_read_events_ring(). */ unsigned tail; unsigned magic; unsigned compat_features; unsigned incompat_features; unsigned header_length; /* size of aio_ring */ struct io_event io_events[0]; }; /* 128 bytes + ring size */ #define AIO_RING_PAGES 8 struct kioctx_table { struct rcu_head rcu; unsigned nr; struct kioctx __rcu *table[]; }; struct kioctx_cpu { unsigned reqs_available; }; struct ctx_rq_wait { struct completion comp; atomic_t count; }; struct kioctx { struct percpu_ref users; atomic_t dead; struct percpu_ref reqs; unsigned long user_id; struct __percpu kioctx_cpu *cpu; /* * For percpu reqs_available, number of slots we move to/from global * counter at a time: */ unsigned req_batch; /* * This is what userspace passed to io_setup(), it's not used for * anything but counting against the global max_reqs quota. * * The real limit is nr_events - 1, which will be larger (see * aio_setup_ring()) */ unsigned max_reqs; /* Size of ringbuffer, in units of struct io_event */ unsigned nr_events; unsigned long mmap_base; unsigned long mmap_size; struct page **ring_pages; long nr_pages; struct rcu_work free_rwork; /* see free_ioctx() */ /* * signals when all in-flight requests are done */ struct ctx_rq_wait *rq_wait; struct { /* * This counts the number of available slots in the ringbuffer, * so we avoid overflowing it: it's decremented (if positive) * when allocating a kiocb and incremented when the resulting * io_event is pulled off the ringbuffer. * * We batch accesses to it with a percpu version. */ atomic_t reqs_available; } ____cacheline_aligned_in_smp; struct { spinlock_t ctx_lock; struct list_head active_reqs; /* used for cancellation */ } ____cacheline_aligned_in_smp; struct { struct mutex ring_lock; wait_queue_head_t wait; } ____cacheline_aligned_in_smp; struct { unsigned tail; unsigned completed_events; spinlock_t completion_lock; } ____cacheline_aligned_in_smp; struct page *internal_pages[AIO_RING_PAGES]; struct file *aio_ring_file; unsigned id; }; struct fsync_iocb { struct work_struct work; struct file *file; bool datasync; }; struct poll_iocb { struct file *file; struct wait_queue_head *head; __poll_t events; bool woken; bool cancelled; struct wait_queue_entry wait; struct work_struct work; }; struct aio_kiocb { union { struct kiocb rw; struct fsync_iocb fsync; struct poll_iocb poll; }; struct kioctx *ki_ctx; kiocb_cancel_fn *ki_cancel; struct iocb __user *ki_user_iocb; /* user's aiocb */ __u64 ki_user_data; /* user's data for completion */ struct list_head ki_list; /* the aio core uses this * for cancellation */ refcount_t ki_refcnt; /* * If the aio_resfd field of the userspace iocb is not zero, * this is the underlying eventfd context to deliver events to. */ struct eventfd_ctx *ki_eventfd; }; /*------ sysctl variables----*/ static DEFINE_SPINLOCK(aio_nr_lock); unsigned long aio_nr; /* current system wide number of aio requests */ unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ /*----end sysctl variables---*/ static struct kmem_cache *kiocb_cachep; static struct kmem_cache *kioctx_cachep; static struct vfsmount *aio_mnt; static const struct file_operations aio_ring_fops; static const struct address_space_operations aio_ctx_aops; static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) { struct file *file; struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb); if (IS_ERR(inode)) return ERR_CAST(inode); inode->i_mapping->a_ops = &aio_ctx_aops; inode->i_mapping->private_data = ctx; inode->i_size = PAGE_SIZE * nr_pages; file = alloc_file_pseudo(inode, aio_mnt, "[aio]", O_RDWR, &aio_ring_fops); if (IS_ERR(file)) iput(inode); return file; } static struct dentry *aio_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, NULL, AIO_RING_MAGIC); if (!IS_ERR(root)) root->d_sb->s_iflags |= SB_I_NOEXEC; return root; } /* aio_setup * Creates the slab caches used by the aio routines, panic on * failure as this is done early during the boot sequence. */ static int __init aio_setup(void) { static struct file_system_type aio_fs = { .name = "aio", .mount = aio_mount, .kill_sb = kill_anon_super, }; aio_mnt = kern_mount(&aio_fs); if (IS_ERR(aio_mnt)) panic("Failed to create aio fs mount."); kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); return 0; } __initcall(aio_setup); static void put_aio_ring_file(struct kioctx *ctx) { struct file *aio_ring_file = ctx->aio_ring_file; struct address_space *i_mapping; if (aio_ring_file) { truncate_setsize(file_inode(aio_ring_file), 0); /* Prevent further access to the kioctx from migratepages */ i_mapping = aio_ring_file->f_mapping; spin_lock(&i_mapping->private_lock); i_mapping->private_data = NULL; ctx->aio_ring_file = NULL; spin_unlock(&i_mapping->private_lock); fput(aio_ring_file); } } static void aio_free_ring(struct kioctx *ctx) { int i; /* Disconnect the kiotx from the ring file. This prevents future * accesses to the kioctx from page migration. */ put_aio_ring_file(ctx); for (i = 0; i < ctx->nr_pages; i++) { struct page *page; pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i, page_count(ctx->ring_pages[i])); page = ctx->ring_pages[i]; if (!page) continue; ctx->ring_pages[i] = NULL; put_page(page); } if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) { kfree(ctx->ring_pages); ctx->ring_pages = NULL; } } static int aio_ring_mremap(struct vm_area_struct *vma) { struct file *file = vma->vm_file; struct mm_struct *mm = vma->vm_mm; struct kioctx_table *table; int i, res = -EINVAL; spin_lock(&mm->ioctx_lock); rcu_read_lock(); table = rcu_dereference(mm->ioctx_table); for (i = 0; i < table->nr; i++) { struct kioctx *ctx; ctx = rcu_dereference(table->table[i]); if (ctx && ctx->aio_ring_file == file) { if (!atomic_read(&ctx->dead)) { ctx->user_id = ctx->mmap_base = vma->vm_start; res = 0; } break; } } rcu_read_unlock(); spin_unlock(&mm->ioctx_lock); return res; } static const struct vm_operations_struct aio_ring_vm_ops = { .mremap = aio_ring_mremap, #if IS_ENABLED(CONFIG_MMU) .fault = filemap_fault, .map_pages = filemap_map_pages, .page_mkwrite = filemap_page_mkwrite, #endif }; static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma) { vma->vm_flags |= VM_DONTEXPAND; vma->vm_ops = &aio_ring_vm_ops; return 0; } static const struct file_operations aio_ring_fops = { .mmap = aio_ring_mmap, }; #if IS_ENABLED(CONFIG_MIGRATION) static int aio_migratepage(struct address_space *mapping, struct page *new, struct page *old, enum migrate_mode mode) { struct kioctx *ctx; unsigned long flags; pgoff_t idx; int rc; /* * We cannot support the _NO_COPY case here, because copy needs to * happen under the ctx->completion_lock. That does not work with the * migration workflow of MIGRATE_SYNC_NO_COPY. */ if (mode == MIGRATE_SYNC_NO_COPY) return -EINVAL; rc = 0; /* mapping->private_lock here protects against the kioctx teardown. */ spin_lock(&mapping->private_lock); ctx = mapping->private_data; if (!ctx) { rc = -EINVAL; goto out; } /* The ring_lock mutex. The prevents aio_read_events() from writing * to the ring's head, and prevents page migration from mucking in * a partially initialized kiotx. */ if (!mutex_trylock(&ctx->ring_lock)) { rc = -EAGAIN; goto out; } idx = old->index; if (idx < (pgoff_t)ctx->nr_pages) { /* Make sure the old page hasn't already been changed */ if (ctx->ring_pages[idx] != old) rc = -EAGAIN; } else rc = -EINVAL; if (rc != 0) goto out_unlock; /* Writeback must be complete */ BUG_ON(PageWriteback(old)); get_page(new); rc = migrate_page_move_mapping(mapping, new, old, NULL, mode, 1); if (rc != MIGRATEPAGE_SUCCESS) { put_page(new); goto out_unlock; } /* Take completion_lock to prevent other writes to the ring buffer * while the old page is copied to the new. This prevents new * events from being lost. */ spin_lock_irqsave(&ctx->completion_lock, flags); migrate_page_copy(new, old); BUG_ON(ctx->ring_pages[idx] != old); ctx->ring_pages[idx] = new; spin_unlock_irqrestore(&ctx->completion_lock, flags); /* The old page is no longer accessible. */ put_page(old); out_unlock: mutex_unlock(&ctx->ring_lock); out: spin_unlock(&mapping->private_lock); return rc; } #endif static const struct address_space_operations aio_ctx_aops = { .set_page_dirty = __set_page_dirty_no_writeback, #if IS_ENABLED(CONFIG_MIGRATION) .migratepage = aio_migratepage, #endif }; static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events) { struct aio_ring *ring; struct mm_struct *mm = current->mm; unsigned long size, unused; int nr_pages; int i; struct file *file; /* Compensate for the ring buffer's head/tail overlap entry */ nr_events += 2; /* 1 is required, 2 for good luck */ size = sizeof(struct aio_ring); size += sizeof(struct io_event) * nr_events; nr_pages = PFN_UP(size); if (nr_pages < 0) return -EINVAL; file = aio_private_file(ctx, nr_pages); if (IS_ERR(file)) { ctx->aio_ring_file = NULL; return -ENOMEM; } ctx->aio_ring_file = file; nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); ctx->ring_pages = ctx->internal_pages; if (nr_pages > AIO_RING_PAGES) { ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); if (!ctx->ring_pages) { put_aio_ring_file(ctx); return -ENOMEM; } } for (i = 0; i < nr_pages; i++) { struct page *page; page = find_or_create_page(file->f_mapping, i, GFP_HIGHUSER | __GFP_ZERO); if (!page) break; pr_debug("pid(%d) page[%d]->count=%d\n", current->pid, i, page_count(page)); SetPageUptodate(page); unlock_page(page); ctx->ring_pages[i] = page; } ctx->nr_pages = i; if (unlikely(i != nr_pages)) { aio_free_ring(ctx); return -ENOMEM; } ctx->mmap_size = nr_pages * PAGE_SIZE; pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size); if (down_write_killable(&mm->mmap_sem)) { ctx->mmap_size = 0; aio_free_ring(ctx); return -EINTR; } ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, 0, &unused, NULL); up_write(&mm->mmap_sem); if (IS_ERR((void *)ctx->mmap_base)) { ctx->mmap_size = 0; aio_free_ring(ctx); return -ENOMEM; } pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base); ctx->user_id = ctx->mmap_base; ctx->nr_events = nr_events; /* trusted copy */ ring = kmap_atomic(ctx->ring_pages[0]); ring->nr = nr_events; /* user copy */ ring->id = ~0U; ring->head = ring->tail = 0; ring->magic = AIO_RING_MAGIC; ring->compat_features = AIO_RING_COMPAT_FEATURES; ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; ring->header_length = sizeof(struct aio_ring); kunmap_atomic(ring); flush_dcache_page(ctx->ring_pages[0]); return 0; } #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) { struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw); struct kioctx *ctx = req->ki_ctx; unsigned long flags; if (WARN_ON_ONCE(!list_empty(&req->ki_list))) return; spin_lock_irqsave(&ctx->ctx_lock, flags); list_add_tail(&req->ki_list, &ctx->active_reqs); req->ki_cancel = cancel; spin_unlock_irqrestore(&ctx->ctx_lock, flags); } EXPORT_SYMBOL(kiocb_set_cancel_fn); /* * free_ioctx() should be RCU delayed to synchronize against the RCU * protected lookup_ioctx() and also needs process context to call * aio_free_ring(). Use rcu_work. */ static void free_ioctx(struct work_struct *work) { struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx, free_rwork); pr_debug("freeing %p\n", ctx); aio_free_ring(ctx); free_percpu(ctx->cpu); percpu_ref_exit(&ctx->reqs); percpu_ref_exit(&ctx->users); kmem_cache_free(kioctx_cachep, ctx); } static void free_ioctx_reqs(struct percpu_ref *ref) { struct kioctx *ctx = container_of(ref, struct kioctx, reqs); /* At this point we know that there are no any in-flight requests */ if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count)) complete(&ctx->rq_wait->comp); /* Synchronize against RCU protected table->table[] dereferences */ INIT_RCU_WORK(&ctx->free_rwork, free_ioctx); queue_rcu_work(system_wq, &ctx->free_rwork); } /* * When this function runs, the kioctx has been removed from the "hash table" * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted - * now it's safe to cancel any that need to be. */ static void free_ioctx_users(struct percpu_ref *ref) { struct kioctx *ctx = container_of(ref, struct kioctx, users); struct aio_kiocb *req; spin_lock_irq(&ctx->ctx_lock); while (!list_empty(&ctx->active_reqs)) { req = list_first_entry(&ctx->active_reqs, struct aio_kiocb, ki_list); req->ki_cancel(&req->rw); list_del_init(&req->ki_list); } spin_unlock_irq(&ctx->ctx_lock); percpu_ref_kill(&ctx->reqs); percpu_ref_put(&ctx->reqs); } static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) { unsigned i, new_nr; struct kioctx_table *table, *old; struct aio_ring *ring; spin_lock(&mm->ioctx_lock); table = rcu_dereference_raw(mm->ioctx_table); while (1) { if (table) for (i = 0; i < table->nr; i++) if (!rcu_access_pointer(table->table[i])) { ctx->id = i; rcu_assign_pointer(table->table[i], ctx); spin_unlock(&mm->ioctx_lock); /* While kioctx setup is in progress, * we are protected from page migration * changes ring_pages by ->ring_lock. */ ring = kmap_atomic(ctx->ring_pages[0]); ring->id = ctx->id; kunmap_atomic(ring); return 0; } new_nr = (table ? table->nr : 1) * 4; spin_unlock(&mm->ioctx_lock); table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) * new_nr, GFP_KERNEL); if (!table) return -ENOMEM; table->nr = new_nr; spin_lock(&mm->ioctx_lock); old = rcu_dereference_raw(mm->ioctx_table); if (!old) { rcu_assign_pointer(mm->ioctx_table, table); } else if (table->nr > old->nr) { memcpy(table->table, old->table, old->nr * sizeof(struct kioctx *)); rcu_assign_pointer(mm->ioctx_table, table); kfree_rcu(old, rcu); } else { kfree(table); table = old; } } } static void aio_nr_sub(unsigned nr) { spin_lock(&aio_nr_lock); if (WARN_ON(aio_nr - nr > aio_nr)) aio_nr = 0; else aio_nr -= nr; spin_unlock(&aio_nr_lock); } /* ioctx_alloc * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. */ static struct kioctx *ioctx_alloc(unsigned nr_events) { struct mm_struct *mm = current->mm; struct kioctx *ctx; int err = -ENOMEM; /* * Store the original nr_events -- what userspace passed to io_setup(), * for counting against the global limit -- before it changes. */ unsigned int max_reqs = nr_events; /* * We keep track of the number of available ringbuffer slots, to prevent * overflow (reqs_available), and we also use percpu counters for this. * * So since up to half the slots might be on other cpu's percpu counters * and unavailable, double nr_events so userspace sees what they * expected: additionally, we move req_batch slots to/from percpu * counters at a time, so make sure that isn't 0: */ nr_events = max(nr_events, num_possible_cpus() * 4); nr_events *= 2; /* Prevent overflows */ if (nr_events > (0x10000000U / sizeof(struct io_event))) { pr_debug("ENOMEM: nr_events too high\n"); return ERR_PTR(-EINVAL); } if (!nr_events || (unsigned long)max_reqs > aio_max_nr) return ERR_PTR(-EAGAIN); ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); if (!ctx) return ERR_PTR(-ENOMEM); ctx->max_reqs = max_reqs; spin_lock_init(&ctx->ctx_lock); spin_lock_init(&ctx->completion_lock); mutex_init(&ctx->ring_lock); /* Protect against page migration throughout kiotx setup by keeping * the ring_lock mutex held until setup is complete. */ mutex_lock(&ctx->ring_lock); init_waitqueue_head(&ctx->wait); INIT_LIST_HEAD(&ctx->active_reqs); if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL)) goto err; if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL)) goto err; ctx->cpu = alloc_percpu(struct kioctx_cpu); if (!ctx->cpu) goto err; err = aio_setup_ring(ctx, nr_events); if (err < 0) goto err; atomic_set(&ctx->reqs_available, ctx->nr_events - 1); ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4); if (ctx->req_batch < 1) ctx->req_batch = 1; /* limit the number of system wide aios */ spin_lock(&aio_nr_lock); if (aio_nr + ctx->max_reqs > aio_max_nr || aio_nr + ctx->max_reqs < aio_nr) { spin_unlock(&aio_nr_lock); err = -EAGAIN; goto err_ctx; } aio_nr += ctx->max_reqs; spin_unlock(&aio_nr_lock); percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */ percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */ err = ioctx_add_table(ctx, mm); if (err) goto err_cleanup; /* Release the ring_lock mutex now that all setup is complete. */ mutex_unlock(&ctx->ring_lock); pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", ctx, ctx->user_id, mm, ctx->nr_events); return ctx; err_cleanup: aio_nr_sub(ctx->max_reqs); err_ctx: atomic_set(&ctx->dead, 1); if (ctx->mmap_size) vm_munmap(ctx->mmap_base, ctx->mmap_size); aio_free_ring(ctx); err: mutex_unlock(&ctx->ring_lock); free_percpu(ctx->cpu); percpu_ref_exit(&ctx->reqs); percpu_ref_exit(&ctx->users); kmem_cache_free(kioctx_cachep, ctx); pr_debug("error allocating ioctx %d\n", err); return ERR_PTR(err); } /* kill_ioctx * Cancels all outstanding aio requests on an aio context. Used * when the processes owning a context have all exited to encourage * the rapid destruction of the kioctx. */ static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx, struct ctx_rq_wait *wait) { struct kioctx_table *table; spin_lock(&mm->ioctx_lock); if (atomic_xchg(&ctx->dead, 1)) { spin_unlock(&mm->ioctx_lock); return -EINVAL; } table = rcu_dereference_raw(mm->ioctx_table); WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id])); RCU_INIT_POINTER(table->table[ctx->id], NULL); spin_unlock(&mm->ioctx_lock); /* free_ioctx_reqs() will do the necessary RCU synchronization */ wake_up_all(&ctx->wait); /* * It'd be more correct to do this in free_ioctx(), after all * the outstanding kiocbs have finished - but by then io_destroy * has already returned, so io_setup() could potentially return * -EAGAIN with no ioctxs actually in use (as far as userspace * could tell). */ aio_nr_sub(ctx->max_reqs); if (ctx->mmap_size) vm_munmap(ctx->mmap_base, ctx->mmap_size); ctx->rq_wait = wait; percpu_ref_kill(&ctx->users); return 0; } /* * exit_aio: called when the last user of mm goes away. At this point, there is * no way for any new requests to be submited or any of the io_* syscalls to be * called on the context. * * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on * them. */ void exit_aio(struct mm_struct *mm) { struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table); struct ctx_rq_wait wait; int i, skipped; if (!table) return; atomic_set(&wait.count, table->nr); init_completion(&wait.comp); skipped = 0; for (i = 0; i < table->nr; ++i) { struct kioctx *ctx = rcu_dereference_protected(table->table[i], true); if (!ctx) { skipped++; continue; } /* * We don't need to bother with munmap() here - exit_mmap(mm) * is coming and it'll unmap everything. And we simply can't, * this is not necessarily our ->mm. * Since kill_ioctx() uses non-zero ->mmap_size as indicator * that it needs to unmap the area, just set it to 0. */ ctx->mmap_size = 0; kill_ioctx(mm, ctx, &wait); } if (!atomic_sub_and_test(skipped, &wait.count)) { /* Wait until all IO for the context are done. */ wait_for_completion(&wait.comp); } RCU_INIT_POINTER(mm->ioctx_table, NULL); kfree(table); } static void put_reqs_available(struct kioctx *ctx, unsigned nr) { struct kioctx_cpu *kcpu; unsigned long flags; local_irq_save(flags); kcpu = this_cpu_ptr(ctx->cpu); kcpu->reqs_available += nr; while (kcpu->reqs_available >= ctx->req_batch * 2) { kcpu->reqs_available -= ctx->req_batch; atomic_add(ctx->req_batch, &ctx->reqs_available); } local_irq_restore(flags); } static bool get_reqs_available(struct kioctx *ctx) { struct kioctx_cpu *kcpu; bool ret = false; unsigned long flags; local_irq_save(flags); kcpu = this_cpu_ptr(ctx->cpu); if (!kcpu->reqs_available) { int old, avail = atomic_read(&ctx->reqs_available); do { if (avail < ctx->req_batch) goto out; old = avail; avail = atomic_cmpxchg(&ctx->reqs_available, avail, avail - ctx->req_batch); } while (avail != old); kcpu->reqs_available += ctx->req_batch; } ret = true; kcpu->reqs_available--; out: local_irq_restore(flags); return ret; } /* refill_reqs_available * Updates the reqs_available reference counts used for tracking the * number of free slots in the completion ring. This can be called * from aio_complete() (to optimistically update reqs_available) or * from aio_get_req() (the we're out of events case). It must be * called holding ctx->completion_lock. */ static void refill_reqs_available(struct kioctx *ctx, unsigned head, unsigned tail) { unsigned events_in_ring, completed; /* Clamp head since userland can write to it. */ head %= ctx->nr_events; if (head <= tail) events_in_ring = tail - head; else events_in_ring = ctx->nr_events - (head - tail); completed = ctx->completed_events; if (events_in_ring < completed) completed -= events_in_ring; else completed = 0; if (!completed) return; ctx->completed_events -= completed; put_reqs_available(ctx, completed); } /* user_refill_reqs_available * Called to refill reqs_available when aio_get_req() encounters an * out of space in the completion ring. */ static void user_refill_reqs_available(struct kioctx *ctx) { spin_lock_irq(&ctx->completion_lock); if (ctx->completed_events) { struct aio_ring *ring; unsigned head; /* Access of ring->head may race with aio_read_events_ring() * here, but that's okay since whether we read the old version * or the new version, and either will be valid. The important * part is that head cannot pass tail since we prevent * aio_complete() from updating tail by holding * ctx->completion_lock. Even if head is invalid, the check * against ctx->completed_events below will make sure we do the * safe/right thing. */ ring = kmap_atomic(ctx->ring_pages[0]); head = ring->head; kunmap_atomic(ring); refill_reqs_available(ctx, head, ctx->tail); } spin_unlock_irq(&ctx->completion_lock); } /* aio_get_req * Allocate a slot for an aio request. * Returns NULL if no requests are free. */ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx) { struct aio_kiocb *req; if (!get_reqs_available(ctx)) { user_refill_reqs_available(ctx); if (!get_reqs_available(ctx)) return NULL; } req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO); if (unlikely(!req)) goto out_put; percpu_ref_get(&ctx->reqs); INIT_LIST_HEAD(&req->ki_list); refcount_set(&req->ki_refcnt, 0); req->ki_ctx = ctx; return req; out_put: put_reqs_available(ctx, 1); return NULL; } static struct kioctx *lookup_ioctx(unsigned long ctx_id) { struct aio_ring __user *ring = (void __user *)ctx_id; struct mm_struct *mm = current->mm; struct kioctx *ctx, *ret = NULL; struct kioctx_table *table; unsigned id; if (get_user(id, &ring->id)) return NULL; rcu_read_lock(); table = rcu_dereference(mm->ioctx_table); if (!table || id >= table->nr) goto out; ctx = rcu_dereference(table->table[id]); if (ctx && ctx->user_id == ctx_id) { if (percpu_ref_tryget_live(&ctx->users)) ret = ctx; } out: rcu_read_unlock(); return ret; } static inline void iocb_put(struct aio_kiocb *iocb) { if (refcount_read(&iocb->ki_refcnt) == 0 || refcount_dec_and_test(&iocb->ki_refcnt)) { percpu_ref_put(&iocb->ki_ctx->reqs); kmem_cache_free(kiocb_cachep, iocb); } } /* aio_complete * Called when the io request on the given iocb is complete. */ static void aio_complete(struct aio_kiocb *iocb, long res, long res2) { struct kioctx *ctx = iocb->ki_ctx; struct aio_ring *ring; struct io_event *ev_page, *event; unsigned tail, pos, head; unsigned long flags; /* * Add a completion event to the ring buffer. Must be done holding * ctx->completion_lock to prevent other code from messing with the tail * pointer since we might be called from irq context. */ spin_lock_irqsave(&ctx->completion_lock, flags); tail = ctx->tail; pos = tail + AIO_EVENTS_OFFSET; if (++tail >= ctx->nr_events) tail = 0; ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); event = ev_page + pos % AIO_EVENTS_PER_PAGE; event->obj = (u64)(unsigned long)iocb->ki_user_iocb; event->data = iocb->ki_user_data; event->res = res; event->res2 = res2; kunmap_atomic(ev_page); flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n", ctx, tail, iocb, iocb->ki_user_iocb, iocb->ki_user_data, res, res2); /* after flagging the request as done, we * must never even look at it again */ smp_wmb(); /* make event visible before updating tail */ ctx->tail = tail; ring = kmap_atomic(ctx->ring_pages[0]); head = ring->head; ring->tail = tail; kunmap_atomic(ring); flush_dcache_page(ctx->ring_pages[0]); ctx->completed_events++; if (ctx->completed_events > 1) refill_reqs_available(ctx, head, tail); spin_unlock_irqrestore(&ctx->completion_lock, flags); pr_debug("added to ring %p at [%u]\n", iocb, tail); /* * Check if the user asked us to deliver the result through an * eventfd. The eventfd_signal() function is safe to be called * from IRQ context. */ if (iocb->ki_eventfd) { eventfd_signal(iocb->ki_eventfd, 1); eventfd_ctx_put(iocb->ki_eventfd); } /* * We have to order our ring_info tail store above and test * of the wait list below outside the wait lock. This is * like in wake_up_bit() where clearing a bit has to be * ordered with the unlocked test. */ smp_mb(); if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); iocb_put(iocb); } /* aio_read_events_ring * Pull an event off of the ioctx's event ring. Returns the number of * events fetched */ static long aio_read_events_ring(struct kioctx *ctx, struct io_event __user *event, long nr) { struct aio_ring *ring; unsigned head, tail, pos; long ret = 0; int copy_ret; /* * The mutex can block and wake us up and that will cause * wait_event_interruptible_hrtimeout() to schedule without sleeping * and repeat. This should be rare enough that it doesn't cause * peformance issues. See the comment in read_events() for more detail. */ sched_annotate_sleep(); mutex_lock(&ctx->ring_lock); /* Access to ->ring_pages here is protected by ctx->ring_lock. */ ring = kmap_atomic(ctx->ring_pages[0]); head = ring->head; tail = ring->tail; kunmap_atomic(ring); /* * Ensure that once we've read the current tail pointer, that * we also see the events that were stored up to the tail. */ smp_rmb(); pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events); if (head == tail) goto out; head %= ctx->nr_events; tail %= ctx->nr_events; while (ret < nr) { long avail; struct io_event *ev; struct page *page; avail = (head <= tail ? tail : ctx->nr_events) - head; if (head == tail) break; pos = head + AIO_EVENTS_OFFSET; page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]; pos %= AIO_EVENTS_PER_PAGE; avail = min(avail, nr - ret); avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos); ev = kmap(page); copy_ret = copy_to_user(event + ret, ev + pos, sizeof(*ev) * avail); kunmap(page); if (unlikely(copy_ret)) { ret = -EFAULT; goto out; } ret += avail; head += avail; head %= ctx->nr_events; } ring = kmap_atomic(ctx->ring_pages[0]); ring->head = head; kunmap_atomic(ring); flush_dcache_page(ctx->ring_pages[0]); pr_debug("%li h%u t%u\n", ret, head, tail); out: mutex_unlock(&ctx->ring_lock); return ret; } static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr, struct io_event __user *event, long *i) { long ret = aio_read_events_ring(ctx, event + *i, nr - *i); if (ret > 0) *i += ret; if (unlikely(atomic_read(&ctx->dead))) ret = -EINVAL; if (!*i) *i = ret; return ret < 0 || *i >= min_nr; } static long read_events(struct kioctx *ctx, long min_nr, long nr, struct io_event __user *event, ktime_t until) { long ret = 0; /* * Note that aio_read_events() is being called as the conditional - i.e. * we're calling it after prepare_to_wait() has set task state to * TASK_INTERRUPTIBLE. * * But aio_read_events() can block, and if it blocks it's going to flip * the task state back to TASK_RUNNING. * * This should be ok, provided it doesn't flip the state back to * TASK_RUNNING and return 0 too much - that causes us to spin. That * will only happen if the mutex_lock() call blocks, and we then find * the ringbuffer empty. So in practice we should be ok, but it's * something to be aware of when touching this code. */ if (until == 0) aio_read_events(ctx, min_nr, nr, event, &ret); else wait_event_interruptible_hrtimeout(ctx->wait, aio_read_events(ctx, min_nr, nr, event, &ret), until); return ret; } /* sys_io_setup: * Create an aio_context capable of receiving at least nr_events. * ctxp must not point to an aio_context that already exists, and * must be initialized to 0 prior to the call. On successful * creation of the aio_context, *ctxp is filled in with the resulting * handle. May fail with -EINVAL if *ctxp is not initialized, * if the specified nr_events exceeds internal limits. May fail * with -EAGAIN if the specified nr_events exceeds the user's limit * of available events. May fail with -ENOMEM if insufficient kernel * resources are available. May fail with -EFAULT if an invalid * pointer is passed for ctxp. Will fail with -ENOSYS if not * implemented. */ SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) { struct kioctx *ioctx = NULL; unsigned long ctx; long ret; ret = get_user(ctx, ctxp); if (unlikely(ret)) goto out; ret = -EINVAL; if (unlikely(ctx || nr_events == 0)) { pr_debug("EINVAL: ctx %lu nr_events %u\n", ctx, nr_events); goto out; } ioctx = ioctx_alloc(nr_events); ret = PTR_ERR(ioctx); if (!IS_ERR(ioctx)) { ret = put_user(ioctx->user_id, ctxp); if (ret) kill_ioctx(current->mm, ioctx, NULL); percpu_ref_put(&ioctx->users); } out: return ret; } #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p) { struct kioctx *ioctx = NULL; unsigned long ctx; long ret; ret = get_user(ctx, ctx32p); if (unlikely(ret)) goto out; ret = -EINVAL; if (unlikely(ctx || nr_events == 0)) { pr_debug("EINVAL: ctx %lu nr_events %u\n", ctx, nr_events); goto out; } ioctx = ioctx_alloc(nr_events); ret = PTR_ERR(ioctx); if (!IS_ERR(ioctx)) { /* truncating is ok because it's a user address */ ret = put_user((u32)ioctx->user_id, ctx32p); if (ret) kill_ioctx(current->mm, ioctx, NULL); percpu_ref_put(&ioctx->users); } out: return ret; } #endif /* sys_io_destroy: * Destroy the aio_context specified. May cancel any outstanding * AIOs and block on completion. Will fail with -ENOSYS if not * implemented. May fail with -EINVAL if the context pointed to * is invalid. */ SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) { struct kioctx *ioctx = lookup_ioctx(ctx); if (likely(NULL != ioctx)) { struct ctx_rq_wait wait; int ret; init_completion(&wait.comp); atomic_set(&wait.count, 1); /* Pass requests_done to kill_ioctx() where it can be set * in a thread-safe way. If we try to set it here then we have * a race condition if two io_destroy() called simultaneously. */ ret = kill_ioctx(current->mm, ioctx, &wait); percpu_ref_put(&ioctx->users); /* Wait until all IO for the context are done. Otherwise kernel * keep using user-space buffers even if user thinks the context * is destroyed. */ if (!ret) wait_for_completion(&wait.comp); return ret; } pr_debug("EINVAL: invalid context id\n"); return -EINVAL; } static void aio_remove_iocb(struct aio_kiocb *iocb) { struct kioctx *ctx = iocb->ki_ctx; unsigned long flags; spin_lock_irqsave(&ctx->ctx_lock, flags); list_del(&iocb->ki_list); spin_unlock_irqrestore(&ctx->ctx_lock, flags); } static void aio_complete_rw(struct kiocb *kiocb, long res, long res2) { struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw); if (!list_empty_careful(&iocb->ki_list)) aio_remove_iocb(iocb); if (kiocb->ki_flags & IOCB_WRITE) { struct inode *inode = file_inode(kiocb->ki_filp); /* * Tell lockdep we inherited freeze protection from submission * thread. */ if (S_ISREG(inode->i_mode)) __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE); file_end_write(kiocb->ki_filp); } fput(kiocb->ki_filp); aio_complete(iocb, res, res2); } static int aio_prep_rw(struct kiocb *req, struct iocb *iocb) { int ret; req->ki_filp = fget(iocb->aio_fildes); if (unlikely(!req->ki_filp)) return -EBADF; req->ki_complete = aio_complete_rw; req->ki_pos = iocb->aio_offset; req->ki_flags = iocb_flags(req->ki_filp); if (iocb->aio_flags & IOCB_FLAG_RESFD) req->ki_flags |= IOCB_EVENTFD; req->ki_hint = ki_hint_validate(file_write_hint(req->ki_filp)); if (iocb->aio_flags & IOCB_FLAG_IOPRIO) { /* * If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then * aio_reqprio is interpreted as an I/O scheduling * class and priority. */ ret = ioprio_check_cap(iocb->aio_reqprio); if (ret) { pr_debug("aio ioprio check cap error: %d\n", ret); return ret; } req->ki_ioprio = iocb->aio_reqprio; } else req->ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags); if (unlikely(ret)) fput(req->ki_filp); return ret; } static int aio_setup_rw(int rw, struct iocb *iocb, struct iovec **iovec, bool vectored, bool compat, struct iov_iter *iter) { void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf; size_t len = iocb->aio_nbytes; if (!vectored) { ssize_t ret = import_single_range(rw, buf, len, *iovec, iter); *iovec = NULL; return ret; } #ifdef CONFIG_COMPAT if (compat) return compat_import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter); #endif return import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter); } static inline void aio_rw_done(struct kiocb *req, ssize_t ret) { switch (ret) { case -EIOCBQUEUED: break; case -ERESTARTSYS: case -ERESTARTNOINTR: case -ERESTARTNOHAND: case -ERESTART_RESTARTBLOCK: /* * There's no easy way to restart the syscall since other AIO's * may be already running. Just fail this IO with EINTR. */ ret = -EINTR; /*FALLTHRU*/ default: aio_complete_rw(req, ret, 0); } } static ssize_t aio_read(struct kiocb *req, struct iocb *iocb, bool vectored, bool compat) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct iov_iter iter; struct file *file; ssize_t ret; ret = aio_prep_rw(req, iocb); if (ret) return ret; file = req->ki_filp; ret = -EBADF; if (unlikely(!(file->f_mode & FMODE_READ))) goto out_fput; ret = -EINVAL; if (unlikely(!file->f_op->read_iter)) goto out_fput; ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter); if (ret) goto out_fput; ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter)); if (!ret) aio_rw_done(req, call_read_iter(file, req, &iter)); kfree(iovec); out_fput: if (unlikely(ret)) fput(file); return ret; } static ssize_t aio_write(struct kiocb *req, struct iocb *iocb, bool vectored, bool compat) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct iov_iter iter; struct file *file; ssize_t ret; ret = aio_prep_rw(req, iocb); if (ret) return ret; file = req->ki_filp; ret = -EBADF; if (unlikely(!(file->f_mode & FMODE_WRITE))) goto out_fput; ret = -EINVAL; if (unlikely(!file->f_op->write_iter)) goto out_fput; ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter); if (ret) goto out_fput; ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter)); if (!ret) { /* * Open-code file_start_write here to grab freeze protection, * which will be released by another thread in * aio_complete_rw(). Fool lockdep by telling it the lock got * released so that it doesn't complain about the held lock when * we return to userspace. */ if (S_ISREG(file_inode(file)->i_mode)) { __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true); __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE); } req->ki_flags |= IOCB_WRITE; aio_rw_done(req, call_write_iter(file, req, &iter)); } kfree(iovec); out_fput: if (unlikely(ret)) fput(file); return ret; } static void aio_fsync_work(struct work_struct *work) { struct fsync_iocb *req = container_of(work, struct fsync_iocb, work); int ret; ret = vfs_fsync(req->file, req->datasync); fput(req->file); aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0); } static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync) { if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)) return -EINVAL; req->file = fget(iocb->aio_fildes); if (unlikely(!req->file)) return -EBADF; if (unlikely(!req->file->f_op->fsync)) { fput(req->file); return -EINVAL; } req->datasync = datasync; INIT_WORK(&req->work, aio_fsync_work); schedule_work(&req->work); return 0; } static inline void aio_poll_complete(struct aio_kiocb *iocb, __poll_t mask) { struct file *file = iocb->poll.file; aio_complete(iocb, mangle_poll(mask), 0); fput(file); } static void aio_poll_complete_work(struct work_struct *work) { struct poll_iocb *req = container_of(work, struct poll_iocb, work); struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll); struct poll_table_struct pt = { ._key = req->events }; struct kioctx *ctx = iocb->ki_ctx; __poll_t mask = 0; if (!READ_ONCE(req->cancelled)) mask = vfs_poll(req->file, &pt) & req->events; /* * Note that ->ki_cancel callers also delete iocb from active_reqs after * calling ->ki_cancel. We need the ctx_lock roundtrip here to * synchronize with them. In the cancellation case the list_del_init * itself is not actually needed, but harmless so we keep it in to * avoid further branches in the fast path. */ spin_lock_irq(&ctx->ctx_lock); if (!mask && !READ_ONCE(req->cancelled)) { add_wait_queue(req->head, &req->wait); spin_unlock_irq(&ctx->ctx_lock); return; } list_del_init(&iocb->ki_list); spin_unlock_irq(&ctx->ctx_lock); aio_poll_complete(iocb, mask); } /* assumes we are called with irqs disabled */ static int aio_poll_cancel(struct kiocb *iocb) { struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw); struct poll_iocb *req = &aiocb->poll; spin_lock(&req->head->lock); WRITE_ONCE(req->cancelled, true); if (!list_empty(&req->wait.entry)) { list_del_init(&req->wait.entry); schedule_work(&aiocb->poll.work); } spin_unlock(&req->head->lock); return 0; } static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct poll_iocb *req = container_of(wait, struct poll_iocb, wait); struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll); __poll_t mask = key_to_poll(key); req->woken = true; /* for instances that support it check for an event match first: */ if (mask) { if (!(mask & req->events)) return 0; /* try to complete the iocb inline if we can: */ if (spin_trylock(&iocb->ki_ctx->ctx_lock)) { list_del(&iocb->ki_list); spin_unlock(&iocb->ki_ctx->ctx_lock); list_del_init(&req->wait.entry); aio_poll_complete(iocb, mask); return 1; } } list_del_init(&req->wait.entry); schedule_work(&req->work); return 1; } struct aio_poll_table { struct poll_table_struct pt; struct aio_kiocb *iocb; int error; }; static void aio_poll_queue_proc(struct file *file, struct wait_queue_head *head, struct poll_table_struct *p) { struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt); /* multiple wait queues per file are not supported */ if (unlikely(pt->iocb->poll.head)) { pt->error = -EINVAL; return; } pt->error = 0; pt->iocb->poll.head = head; add_wait_queue(head, &pt->iocb->poll.wait); } static ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb) { struct kioctx *ctx = aiocb->ki_ctx; struct poll_iocb *req = &aiocb->poll; struct aio_poll_table apt; __poll_t mask; /* reject any unknown events outside the normal event mask. */ if ((u16)iocb->aio_buf != iocb->aio_buf) return -EINVAL; /* reject fields that are not defined for poll */ if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags) return -EINVAL; INIT_WORK(&req->work, aio_poll_complete_work); req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP; req->file = fget(iocb->aio_fildes); if (unlikely(!req->file)) return -EBADF; apt.pt._qproc = aio_poll_queue_proc; apt.pt._key = req->events; apt.iocb = aiocb; apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */ /* initialized the list so that we can do list_empty checks */ INIT_LIST_HEAD(&req->wait.entry); init_waitqueue_func_entry(&req->wait, aio_poll_wake); /* one for removal from waitqueue, one for this function */ refcount_set(&aiocb->ki_refcnt, 2); mask = vfs_poll(req->file, &apt.pt) & req->events; if (unlikely(!req->head)) { /* we did not manage to set up a waitqueue, done */ goto out; } spin_lock_irq(&ctx->ctx_lock); spin_lock(&req->head->lock); if (req->woken) { /* wake_up context handles the rest */ mask = 0; apt.error = 0; } else if (mask || apt.error) { /* if we get an error or a mask we are done */ WARN_ON_ONCE(list_empty(&req->wait.entry)); list_del_init(&req->wait.entry); } else { /* actually waiting for an event */ list_add_tail(&aiocb->ki_list, &ctx->active_reqs); aiocb->ki_cancel = aio_poll_cancel; } spin_unlock(&req->head->lock); spin_unlock_irq(&ctx->ctx_lock); out: if (unlikely(apt.error)) { fput(req->file); return apt.error; } if (mask) aio_poll_complete(aiocb, mask); iocb_put(aiocb); return 0; } static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, bool compat) { struct aio_kiocb *req; struct iocb iocb; ssize_t ret; if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb)))) return -EFAULT; /* enforce forwards compatibility on users */ if (unlikely(iocb.aio_reserved2)) { pr_debug("EINVAL: reserve field set\n"); return -EINVAL; } /* prevent overflows */ if (unlikely( (iocb.aio_buf != (unsigned long)iocb.aio_buf) || (iocb.aio_nbytes != (size_t)iocb.aio_nbytes) || ((ssize_t)iocb.aio_nbytes < 0) )) { pr_debug("EINVAL: overflow check\n"); return -EINVAL; } req = aio_get_req(ctx); if (unlikely(!req)) return -EAGAIN; if (iocb.aio_flags & IOCB_FLAG_RESFD) { /* * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an * instance of the file* now. The file descriptor must be * an eventfd() fd, and will be signaled for each completed * event using the eventfd_signal() function. */ req->ki_eventfd = eventfd_ctx_fdget((int) iocb.aio_resfd); if (IS_ERR(req->ki_eventfd)) { ret = PTR_ERR(req->ki_eventfd); req->ki_eventfd = NULL; goto out_put_req; } } ret = put_user(KIOCB_KEY, &user_iocb->aio_key); if (unlikely(ret)) { pr_debug("EFAULT: aio_key\n"); goto out_put_req; } req->ki_user_iocb = user_iocb; req->ki_user_data = iocb.aio_data; switch (iocb.aio_lio_opcode) { case IOCB_CMD_PREAD: ret = aio_read(&req->rw, &iocb, false, compat); break; case IOCB_CMD_PWRITE: ret = aio_write(&req->rw, &iocb, false, compat); break; case IOCB_CMD_PREADV: ret = aio_read(&req->rw, &iocb, true, compat); break; case IOCB_CMD_PWRITEV: ret = aio_write(&req->rw, &iocb, true, compat); break; case IOCB_CMD_FSYNC: ret = aio_fsync(&req->fsync, &iocb, false); break; case IOCB_CMD_FDSYNC: ret = aio_fsync(&req->fsync, &iocb, true); break; case IOCB_CMD_POLL: ret = aio_poll(req, &iocb); break; default: pr_debug("invalid aio operation %d\n", iocb.aio_lio_opcode); ret = -EINVAL; break; } /* * If ret is 0, we'd either done aio_complete() ourselves or have * arranged for that to be done asynchronously. Anything non-zero * means that we need to destroy req ourselves. */ if (ret) goto out_put_req; return 0; out_put_req: put_reqs_available(ctx, 1); percpu_ref_put(&ctx->reqs); if (req->ki_eventfd) eventfd_ctx_put(req->ki_eventfd); kmem_cache_free(kiocb_cachep, req); return ret; } /* sys_io_submit: * Queue the nr iocbs pointed to by iocbpp for processing. Returns * the number of iocbs queued. May return -EINVAL if the aio_context * specified by ctx_id is invalid, if nr is < 0, if the iocb at * *iocbpp[0] is not properly initialized, if the operation specified * is invalid for the file descriptor in the iocb. May fail with * -EFAULT if any of the data structures point to invalid data. May * fail with -EBADF if the file descriptor specified in the first * iocb is invalid. May fail with -EAGAIN if insufficient resources * are available to queue any iocbs. Will return 0 if nr is 0. Will * fail with -ENOSYS if not implemented. */ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, struct iocb __user * __user *, iocbpp) { struct kioctx *ctx; long ret = 0; int i = 0; struct blk_plug plug; if (unlikely(nr < 0)) return -EINVAL; ctx = lookup_ioctx(ctx_id); if (unlikely(!ctx)) { pr_debug("EINVAL: invalid context id\n"); return -EINVAL; } if (nr > ctx->nr_events) nr = ctx->nr_events; blk_start_plug(&plug); for (i = 0; i < nr; i++) { struct iocb __user *user_iocb; if (unlikely(get_user(user_iocb, iocbpp + i))) { ret = -EFAULT; break; } ret = io_submit_one(ctx, user_iocb, false); if (ret) break; } blk_finish_plug(&plug); percpu_ref_put(&ctx->users); return i ? i : ret; } #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id, int, nr, compat_uptr_t __user *, iocbpp) { struct kioctx *ctx; long ret = 0; int i = 0; struct blk_plug plug; if (unlikely(nr < 0)) return -EINVAL; ctx = lookup_ioctx(ctx_id); if (unlikely(!ctx)) { pr_debug("EINVAL: invalid context id\n"); return -EINVAL; } if (nr > ctx->nr_events) nr = ctx->nr_events; blk_start_plug(&plug); for (i = 0; i < nr; i++) { compat_uptr_t user_iocb; if (unlikely(get_user(user_iocb, iocbpp + i))) { ret = -EFAULT; break; } ret = io_submit_one(ctx, compat_ptr(user_iocb), true); if (ret) break; } blk_finish_plug(&plug); percpu_ref_put(&ctx->users); return i ? i : ret; } #endif /* lookup_kiocb * Finds a given iocb for cancellation. */ static struct aio_kiocb * lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb) { struct aio_kiocb *kiocb; assert_spin_locked(&ctx->ctx_lock); /* TODO: use a hash or array, this sucks. */ list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) { if (kiocb->ki_user_iocb == iocb) return kiocb; } return NULL; } /* sys_io_cancel: * Attempts to cancel an iocb previously passed to io_submit. If * the operation is successfully cancelled, the resulting event is * copied into the memory pointed to by result without being placed * into the completion queue and 0 is returned. May fail with * -EFAULT if any of the data structures pointed to are invalid. * May fail with -EINVAL if aio_context specified by ctx_id is * invalid. May fail with -EAGAIN if the iocb specified was not * cancelled. Will fail with -ENOSYS if not implemented. */ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, struct io_event __user *, result) { struct kioctx *ctx; struct aio_kiocb *kiocb; int ret = -EINVAL; u32 key; if (unlikely(get_user(key, &iocb->aio_key))) return -EFAULT; if (unlikely(key != KIOCB_KEY)) return -EINVAL; ctx = lookup_ioctx(ctx_id); if (unlikely(!ctx)) return -EINVAL; spin_lock_irq(&ctx->ctx_lock); kiocb = lookup_kiocb(ctx, iocb); if (kiocb) { ret = kiocb->ki_cancel(&kiocb->rw); list_del_init(&kiocb->ki_list); } spin_unlock_irq(&ctx->ctx_lock); if (!ret) { /* * The result argument is no longer used - the io_event is * always delivered via the ring buffer. -EINPROGRESS indicates * cancellation is progress: */ ret = -EINPROGRESS; } percpu_ref_put(&ctx->users); return ret; } static long do_io_getevents(aio_context_t ctx_id, long min_nr, long nr, struct io_event __user *events, struct timespec64 *ts) { ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX; struct kioctx *ioctx = lookup_ioctx(ctx_id); long ret = -EINVAL; if (likely(ioctx)) { if (likely(min_nr <= nr && min_nr >= 0)) ret = read_events(ioctx, min_nr, nr, events, until); percpu_ref_put(&ioctx->users); } return ret; } /* io_getevents: * Attempts to read at least min_nr events and up to nr events from * the completion queue for the aio_context specified by ctx_id. If * it succeeds, the number of read events is returned. May fail with * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is * out of range, if timeout is out of range. May fail with -EFAULT * if any of the memory specified is invalid. May return 0 or * < min_nr if the timeout specified by timeout has elapsed * before sufficient events are available, where timeout == NULL * specifies an infinite timeout. Note that the timeout pointed to by * timeout is relative. Will fail with -ENOSYS if not implemented. */ SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, long, min_nr, long, nr, struct io_event __user *, events, struct timespec __user *, timeout) { struct timespec64 ts; int ret; if (timeout && unlikely(get_timespec64(&ts, timeout))) return -EFAULT; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); if (!ret && signal_pending(current)) ret = -EINTR; return ret; } struct __aio_sigset { const sigset_t __user *sigmask; size_t sigsetsize; }; SYSCALL_DEFINE6(io_pgetevents, aio_context_t, ctx_id, long, min_nr, long, nr, struct io_event __user *, events, struct timespec __user *, timeout, const struct __aio_sigset __user *, usig) { struct __aio_sigset ksig = { NULL, }; sigset_t ksigmask, sigsaved; struct timespec64 ts; int ret; if (timeout && unlikely(get_timespec64(&ts, timeout))) return -EFAULT; if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) return -EFAULT; if (ksig.sigmask) { if (ksig.sigsetsize != sizeof(sigset_t)) return -EINVAL; if (copy_from_user(&ksigmask, ksig.sigmask, sizeof(ksigmask))) return -EFAULT; sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP)); sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); } ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); if (signal_pending(current)) { if (ksig.sigmask) { current->saved_sigmask = sigsaved; set_restore_sigmask(); } if (!ret) ret = -ERESTARTNOHAND; } else { if (ksig.sigmask) sigprocmask(SIG_SETMASK, &sigsaved, NULL); } return ret; } #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE5(io_getevents, compat_aio_context_t, ctx_id, compat_long_t, min_nr, compat_long_t, nr, struct io_event __user *, events, struct compat_timespec __user *, timeout) { struct timespec64 t; int ret; if (timeout && compat_get_timespec64(&t, timeout)) return -EFAULT; ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); if (!ret && signal_pending(current)) ret = -EINTR; return ret; } struct __compat_aio_sigset { compat_sigset_t __user *sigmask; compat_size_t sigsetsize; }; COMPAT_SYSCALL_DEFINE6(io_pgetevents, compat_aio_context_t, ctx_id, compat_long_t, min_nr, compat_long_t, nr, struct io_event __user *, events, struct compat_timespec __user *, timeout, const struct __compat_aio_sigset __user *, usig) { struct __compat_aio_sigset ksig = { NULL, }; sigset_t ksigmask, sigsaved; struct timespec64 t; int ret; if (timeout && compat_get_timespec64(&t, timeout)) return -EFAULT; if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) return -EFAULT; if (ksig.sigmask) { if (ksig.sigsetsize != sizeof(compat_sigset_t)) return -EINVAL; if (get_compat_sigset(&ksigmask, ksig.sigmask)) return -EFAULT; sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP)); sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); } ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); if (signal_pending(current)) { if (ksig.sigmask) { current->saved_sigmask = sigsaved; set_restore_sigmask(); } if (!ret) ret = -ERESTARTNOHAND; } else { if (ksig.sigmask) sigprocmask(SIG_SETMASK, &sigsaved, NULL); } return ret; } #endif
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