| /* |
| * 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. |
| * |
| * See ../COPYING for licensing terms. |
| */ |
| #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/uio.h> |
| |
| #define DEBUG 0 |
| |
| #include <linux/sched.h> |
| #include <linux/fs.h> |
| #include <linux/file.h> |
| #include <linux/mm.h> |
| #include <linux/mman.h> |
| #include <linux/mmu_context.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 <asm/kmap_types.h> |
| #include <asm/uaccess.h> |
| |
| #if DEBUG > 1 |
| #define dprintk printk |
| #else |
| #define dprintk(x...) do { ; } while (0) |
| #endif |
| |
| /*------ 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 workqueue_struct *aio_wq; |
| |
| /* Used for rare fput completion. */ |
| static void aio_fput_routine(struct work_struct *); |
| static DECLARE_WORK(fput_work, aio_fput_routine); |
| |
| static DEFINE_SPINLOCK(fput_lock); |
| static LIST_HEAD(fput_head); |
| |
| static void aio_kick_handler(struct work_struct *); |
| static void aio_queue_work(struct kioctx *); |
| |
| /* 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) |
| { |
| kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
| kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
| |
| aio_wq = alloc_workqueue("aio", 0, 1); /* used to limit concurrency */ |
| BUG_ON(!aio_wq); |
| |
| pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page)); |
| |
| return 0; |
| } |
| __initcall(aio_setup); |
| |
| static void aio_free_ring(struct kioctx *ctx) |
| { |
| struct aio_ring_info *info = &ctx->ring_info; |
| long i; |
| |
| for (i=0; i<info->nr_pages; i++) |
| put_page(info->ring_pages[i]); |
| |
| if (info->mmap_size) |
| vm_munmap(ctx->mm, info->mmap_base, info->mmap_size); |
| |
| if (info->ring_pages && info->ring_pages != info->internal_pages) |
| kfree(info->ring_pages); |
| info->ring_pages = NULL; |
| info->nr = 0; |
| } |
| |
| static int aio_setup_ring(struct kioctx *ctx) |
| { |
| struct aio_ring *ring; |
| struct aio_ring_info *info = &ctx->ring_info; |
| unsigned nr_events = ctx->max_reqs; |
| unsigned long size; |
| int nr_pages; |
| |
| /* 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 = (size + PAGE_SIZE-1) >> PAGE_SHIFT; |
| |
| if (nr_pages < 0) |
| return -EINVAL; |
| |
| nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); |
| |
| info->nr = 0; |
| info->ring_pages = info->internal_pages; |
| if (nr_pages > AIO_RING_PAGES) { |
| info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); |
| if (!info->ring_pages) |
| return -ENOMEM; |
| } |
| |
| info->mmap_size = nr_pages * PAGE_SIZE; |
| dprintk("attempting mmap of %lu bytes\n", info->mmap_size); |
| down_write(&ctx->mm->mmap_sem); |
| info->mmap_base = do_mmap(NULL, 0, info->mmap_size, |
| PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, |
| 0); |
| if (IS_ERR((void *)info->mmap_base)) { |
| up_write(&ctx->mm->mmap_sem); |
| info->mmap_size = 0; |
| aio_free_ring(ctx); |
| return -EAGAIN; |
| } |
| |
| dprintk("mmap address: 0x%08lx\n", info->mmap_base); |
| info->nr_pages = get_user_pages(current, ctx->mm, |
| info->mmap_base, nr_pages, |
| 1, 0, info->ring_pages, NULL); |
| up_write(&ctx->mm->mmap_sem); |
| |
| if (unlikely(info->nr_pages != nr_pages)) { |
| aio_free_ring(ctx); |
| return -EAGAIN; |
| } |
| |
| ctx->user_id = info->mmap_base; |
| |
| info->nr = nr_events; /* trusted copy */ |
| |
| ring = kmap_atomic(info->ring_pages[0]); |
| ring->nr = nr_events; /* user copy */ |
| ring->id = ctx->user_id; |
| 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); |
| |
| return 0; |
| } |
| |
| |
| /* aio_ring_event: returns a pointer to the event at the given index from |
| * kmap_atomic(). Release the pointer with put_aio_ring_event(); |
| */ |
| #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) |
| |
| #define aio_ring_event(info, nr) ({ \ |
| unsigned pos = (nr) + AIO_EVENTS_OFFSET; \ |
| struct io_event *__event; \ |
| __event = kmap_atomic( \ |
| (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE]); \ |
| __event += pos % AIO_EVENTS_PER_PAGE; \ |
| __event; \ |
| }) |
| |
| #define put_aio_ring_event(event) do { \ |
| struct io_event *__event = (event); \ |
| (void)__event; \ |
| kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK)); \ |
| } while(0) |
| |
| static void ctx_rcu_free(struct rcu_head *head) |
| { |
| struct kioctx *ctx = container_of(head, struct kioctx, rcu_head); |
| kmem_cache_free(kioctx_cachep, ctx); |
| } |
| |
| /* __put_ioctx |
| * Called when the last user of an aio context has gone away, |
| * and the struct needs to be freed. |
| */ |
| static void __put_ioctx(struct kioctx *ctx) |
| { |
| unsigned nr_events = ctx->max_reqs; |
| BUG_ON(ctx->reqs_active); |
| |
| cancel_delayed_work_sync(&ctx->wq); |
| aio_free_ring(ctx); |
| mmdrop(ctx->mm); |
| ctx->mm = NULL; |
| if (nr_events) { |
| spin_lock(&aio_nr_lock); |
| BUG_ON(aio_nr - nr_events > aio_nr); |
| aio_nr -= nr_events; |
| spin_unlock(&aio_nr_lock); |
| } |
| pr_debug("__put_ioctx: freeing %p\n", ctx); |
| call_rcu(&ctx->rcu_head, ctx_rcu_free); |
| } |
| |
| static inline int try_get_ioctx(struct kioctx *kioctx) |
| { |
| return atomic_inc_not_zero(&kioctx->users); |
| } |
| |
| static inline void put_ioctx(struct kioctx *kioctx) |
| { |
| BUG_ON(atomic_read(&kioctx->users) <= 0); |
| if (unlikely(atomic_dec_and_test(&kioctx->users))) |
| __put_ioctx(kioctx); |
| } |
| |
| /* 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; |
| struct kioctx *ctx; |
| int err = -ENOMEM; |
| |
| /* Prevent overflows */ |
| if ((nr_events > (0x10000000U / sizeof(struct io_event))) || |
| (nr_events > (0x10000000U / sizeof(struct kiocb)))) { |
| pr_debug("ENOMEM: nr_events too high\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| |
| if (!nr_events || (unsigned long)nr_events > aio_max_nr) |
| return ERR_PTR(-EAGAIN); |
| |
| ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); |
| if (!ctx) |
| return ERR_PTR(-ENOMEM); |
| |
| ctx->max_reqs = nr_events; |
| mm = ctx->mm = current->mm; |
| atomic_inc(&mm->mm_count); |
| |
| atomic_set(&ctx->users, 2); |
| spin_lock_init(&ctx->ctx_lock); |
| spin_lock_init(&ctx->ring_info.ring_lock); |
| init_waitqueue_head(&ctx->wait); |
| |
| INIT_LIST_HEAD(&ctx->active_reqs); |
| INIT_LIST_HEAD(&ctx->run_list); |
| INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler); |
| |
| if (aio_setup_ring(ctx) < 0) |
| goto out_freectx; |
| |
| /* limit the number of system wide aios */ |
| spin_lock(&aio_nr_lock); |
| if (aio_nr + nr_events > aio_max_nr || |
| aio_nr + nr_events < aio_nr) { |
| spin_unlock(&aio_nr_lock); |
| goto out_cleanup; |
| } |
| aio_nr += ctx->max_reqs; |
| spin_unlock(&aio_nr_lock); |
| |
| /* now link into global list. */ |
| spin_lock(&mm->ioctx_lock); |
| hlist_add_head_rcu(&ctx->list, &mm->ioctx_list); |
| spin_unlock(&mm->ioctx_lock); |
| |
| dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
| ctx, ctx->user_id, current->mm, ctx->ring_info.nr); |
| return ctx; |
| |
| out_cleanup: |
| err = -EAGAIN; |
| aio_free_ring(ctx); |
| out_freectx: |
| mmdrop(mm); |
| kmem_cache_free(kioctx_cachep, ctx); |
| dprintk("aio: error allocating ioctx %d\n", err); |
| return ERR_PTR(err); |
| } |
| |
| /* kill_ctx |
| * 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 void kill_ctx(struct kioctx *ctx) |
| { |
| int (*cancel)(struct kiocb *, struct io_event *); |
| struct task_struct *tsk = current; |
| DECLARE_WAITQUEUE(wait, tsk); |
| struct io_event res; |
| |
| spin_lock_irq(&ctx->ctx_lock); |
| ctx->dead = 1; |
| while (!list_empty(&ctx->active_reqs)) { |
| struct list_head *pos = ctx->active_reqs.next; |
| struct kiocb *iocb = list_kiocb(pos); |
| list_del_init(&iocb->ki_list); |
| cancel = iocb->ki_cancel; |
| kiocbSetCancelled(iocb); |
| if (cancel) { |
| iocb->ki_users++; |
| spin_unlock_irq(&ctx->ctx_lock); |
| cancel(iocb, &res); |
| spin_lock_irq(&ctx->ctx_lock); |
| } |
| } |
| |
| if (!ctx->reqs_active) |
| goto out; |
| |
| add_wait_queue(&ctx->wait, &wait); |
| set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
| while (ctx->reqs_active) { |
| spin_unlock_irq(&ctx->ctx_lock); |
| io_schedule(); |
| set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
| spin_lock_irq(&ctx->ctx_lock); |
| } |
| __set_task_state(tsk, TASK_RUNNING); |
| remove_wait_queue(&ctx->wait, &wait); |
| |
| out: |
| spin_unlock_irq(&ctx->ctx_lock); |
| } |
| |
| /* wait_on_sync_kiocb: |
| * Waits on the given sync kiocb to complete. |
| */ |
| ssize_t wait_on_sync_kiocb(struct kiocb *iocb) |
| { |
| while (iocb->ki_users) { |
| set_current_state(TASK_UNINTERRUPTIBLE); |
| if (!iocb->ki_users) |
| break; |
| io_schedule(); |
| } |
| __set_current_state(TASK_RUNNING); |
| return iocb->ki_user_data; |
| } |
| EXPORT_SYMBOL(wait_on_sync_kiocb); |
| |
| /* 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. However, there may be |
| * outstanding requests which hold references to the context; as they |
| * go away, they will call put_ioctx and release any pinned memory |
| * associated with the request (held via struct page * references). |
| */ |
| void exit_aio(struct mm_struct *mm) |
| { |
| struct kioctx *ctx; |
| |
| while (!hlist_empty(&mm->ioctx_list)) { |
| ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list); |
| hlist_del_rcu(&ctx->list); |
| |
| kill_ctx(ctx); |
| |
| if (1 != atomic_read(&ctx->users)) |
| printk(KERN_DEBUG |
| "exit_aio:ioctx still alive: %d %d %d\n", |
| atomic_read(&ctx->users), ctx->dead, |
| ctx->reqs_active); |
| put_ioctx(ctx); |
| } |
| } |
| |
| /* aio_get_req |
| * Allocate a slot for an aio request. Increments the users count |
| * of the kioctx so that the kioctx stays around until all requests are |
| * complete. Returns NULL if no requests are free. |
| * |
| * Returns with kiocb->users set to 2. The io submit code path holds |
| * an extra reference while submitting the i/o. |
| * This prevents races between the aio code path referencing the |
| * req (after submitting it) and aio_complete() freeing the req. |
| */ |
| static struct kiocb *__aio_get_req(struct kioctx *ctx) |
| { |
| struct kiocb *req = NULL; |
| |
| req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); |
| if (unlikely(!req)) |
| return NULL; |
| |
| req->ki_flags = 0; |
| req->ki_users = 2; |
| req->ki_key = 0; |
| req->ki_ctx = ctx; |
| req->ki_cancel = NULL; |
| req->ki_retry = NULL; |
| req->ki_dtor = NULL; |
| req->private = NULL; |
| req->ki_iovec = NULL; |
| INIT_LIST_HEAD(&req->ki_run_list); |
| req->ki_eventfd = NULL; |
| |
| return req; |
| } |
| |
| /* |
| * struct kiocb's are allocated in batches to reduce the number of |
| * times the ctx lock is acquired and released. |
| */ |
| #define KIOCB_BATCH_SIZE 32L |
| struct kiocb_batch { |
| struct list_head head; |
| long count; /* number of requests left to allocate */ |
| }; |
| |
| static void kiocb_batch_init(struct kiocb_batch *batch, long total) |
| { |
| INIT_LIST_HEAD(&batch->head); |
| batch->count = total; |
| } |
| |
| static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch) |
| { |
| struct kiocb *req, *n; |
| |
| if (list_empty(&batch->head)) |
| return; |
| |
| spin_lock_irq(&ctx->ctx_lock); |
| list_for_each_entry_safe(req, n, &batch->head, ki_batch) { |
| list_del(&req->ki_batch); |
| list_del(&req->ki_list); |
| kmem_cache_free(kiocb_cachep, req); |
| ctx->reqs_active--; |
| } |
| if (unlikely(!ctx->reqs_active && ctx->dead)) |
| wake_up_all(&ctx->wait); |
| spin_unlock_irq(&ctx->ctx_lock); |
| } |
| |
| /* |
| * Allocate a batch of kiocbs. This avoids taking and dropping the |
| * context lock a lot during setup. |
| */ |
| static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch) |
| { |
| unsigned short allocated, to_alloc; |
| long avail; |
| bool called_fput = false; |
| struct kiocb *req, *n; |
| struct aio_ring *ring; |
| |
| to_alloc = min(batch->count, KIOCB_BATCH_SIZE); |
| for (allocated = 0; allocated < to_alloc; allocated++) { |
| req = __aio_get_req(ctx); |
| if (!req) |
| /* allocation failed, go with what we've got */ |
| break; |
| list_add(&req->ki_batch, &batch->head); |
| } |
| |
| if (allocated == 0) |
| goto out; |
| |
| retry: |
| spin_lock_irq(&ctx->ctx_lock); |
| ring = kmap_atomic(ctx->ring_info.ring_pages[0]); |
| |
| avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active; |
| BUG_ON(avail < 0); |
| if (avail == 0 && !called_fput) { |
| /* |
| * Handle a potential starvation case. It is possible that |
| * we hold the last reference on a struct file, causing us |
| * to delay the final fput to non-irq context. In this case, |
| * ctx->reqs_active is artificially high. Calling the fput |
| * routine here may free up a slot in the event completion |
| * ring, allowing this allocation to succeed. |
| */ |
| kunmap_atomic(ring); |
| spin_unlock_irq(&ctx->ctx_lock); |
| aio_fput_routine(NULL); |
| called_fput = true; |
| goto retry; |
| } |
| |
| if (avail < allocated) { |
| /* Trim back the number of requests. */ |
| list_for_each_entry_safe(req, n, &batch->head, ki_batch) { |
| list_del(&req->ki_batch); |
| kmem_cache_free(kiocb_cachep, req); |
| if (--allocated <= avail) |
| break; |
| } |
| } |
| |
| batch->count -= allocated; |
| list_for_each_entry(req, &batch->head, ki_batch) { |
| list_add(&req->ki_list, &ctx->active_reqs); |
| ctx->reqs_active++; |
| } |
| |
| kunmap_atomic(ring); |
| spin_unlock_irq(&ctx->ctx_lock); |
| |
| out: |
| return allocated; |
| } |
| |
| static inline struct kiocb *aio_get_req(struct kioctx *ctx, |
| struct kiocb_batch *batch) |
| { |
| struct kiocb *req; |
| |
| if (list_empty(&batch->head)) |
| if (kiocb_batch_refill(ctx, batch) == 0) |
| return NULL; |
| req = list_first_entry(&batch->head, struct kiocb, ki_batch); |
| list_del(&req->ki_batch); |
| return req; |
| } |
| |
| static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) |
| { |
| assert_spin_locked(&ctx->ctx_lock); |
| |
| if (req->ki_eventfd != NULL) |
| eventfd_ctx_put(req->ki_eventfd); |
| if (req->ki_dtor) |
| req->ki_dtor(req); |
| if (req->ki_iovec != &req->ki_inline_vec) |
| kfree(req->ki_iovec); |
| kmem_cache_free(kiocb_cachep, req); |
| ctx->reqs_active--; |
| |
| if (unlikely(!ctx->reqs_active && ctx->dead)) |
| wake_up_all(&ctx->wait); |
| } |
| |
| static void aio_fput_routine(struct work_struct *data) |
| { |
| spin_lock_irq(&fput_lock); |
| while (likely(!list_empty(&fput_head))) { |
| struct kiocb *req = list_kiocb(fput_head.next); |
| struct kioctx *ctx = req->ki_ctx; |
| |
| list_del(&req->ki_list); |
| spin_unlock_irq(&fput_lock); |
| |
| /* Complete the fput(s) */ |
| if (req->ki_filp != NULL) |
| fput(req->ki_filp); |
| |
| /* Link the iocb into the context's free list */ |
| rcu_read_lock(); |
| spin_lock_irq(&ctx->ctx_lock); |
| really_put_req(ctx, req); |
| /* |
| * at that point ctx might've been killed, but actual |
| * freeing is RCU'd |
| */ |
| spin_unlock_irq(&ctx->ctx_lock); |
| rcu_read_unlock(); |
| |
| spin_lock_irq(&fput_lock); |
| } |
| spin_unlock_irq(&fput_lock); |
| } |
| |
| /* __aio_put_req |
| * Returns true if this put was the last user of the request. |
| */ |
| static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) |
| { |
| dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n", |
| req, atomic_long_read(&req->ki_filp->f_count)); |
| |
| assert_spin_locked(&ctx->ctx_lock); |
| |
| req->ki_users--; |
| BUG_ON(req->ki_users < 0); |
| if (likely(req->ki_users)) |
| return 0; |
| list_del(&req->ki_list); /* remove from active_reqs */ |
| req->ki_cancel = NULL; |
| req->ki_retry = NULL; |
| |
| /* |
| * Try to optimize the aio and eventfd file* puts, by avoiding to |
| * schedule work in case it is not final fput() time. In normal cases, |
| * we would not be holding the last reference to the file*, so |
| * this function will be executed w/out any aio kthread wakeup. |
| */ |
| if (unlikely(!fput_atomic(req->ki_filp))) { |
| spin_lock(&fput_lock); |
| list_add(&req->ki_list, &fput_head); |
| spin_unlock(&fput_lock); |
| schedule_work(&fput_work); |
| } else { |
| req->ki_filp = NULL; |
| really_put_req(ctx, req); |
| } |
| return 1; |
| } |
| |
| /* aio_put_req |
| * Returns true if this put was the last user of the kiocb, |
| * false if the request is still in use. |
| */ |
| int aio_put_req(struct kiocb *req) |
| { |
| struct kioctx *ctx = req->ki_ctx; |
| int ret; |
| spin_lock_irq(&ctx->ctx_lock); |
| ret = __aio_put_req(ctx, req); |
| spin_unlock_irq(&ctx->ctx_lock); |
| return ret; |
| } |
| EXPORT_SYMBOL(aio_put_req); |
| |
| static struct kioctx *lookup_ioctx(unsigned long ctx_id) |
| { |
| struct mm_struct *mm = current->mm; |
| struct kioctx *ctx, *ret = NULL; |
| struct hlist_node *n; |
| |
| rcu_read_lock(); |
| |
| hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) { |
| /* |
| * RCU protects us against accessing freed memory but |
| * we have to be careful not to get a reference when the |
| * reference count already dropped to 0 (ctx->dead test |
| * is unreliable because of races). |
| */ |
| if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){ |
| ret = ctx; |
| break; |
| } |
| } |
| |
| rcu_read_unlock(); |
| return ret; |
| } |
| |
| /* |
| * Queue up a kiocb to be retried. Assumes that the kiocb |
| * has already been marked as kicked, and places it on |
| * the retry run list for the corresponding ioctx, if it |
| * isn't already queued. Returns 1 if it actually queued |
| * the kiocb (to tell the caller to activate the work |
| * queue to process it), or 0, if it found that it was |
| * already queued. |
| */ |
| static inline int __queue_kicked_iocb(struct kiocb *iocb) |
| { |
| struct kioctx *ctx = iocb->ki_ctx; |
| |
| assert_spin_locked(&ctx->ctx_lock); |
| |
| if (list_empty(&iocb->ki_run_list)) { |
| list_add_tail(&iocb->ki_run_list, |
| &ctx->run_list); |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* aio_run_iocb |
| * This is the core aio execution routine. It is |
| * invoked both for initial i/o submission and |
| * subsequent retries via the aio_kick_handler. |
| * Expects to be invoked with iocb->ki_ctx->lock |
| * already held. The lock is released and reacquired |
| * as needed during processing. |
| * |
| * Calls the iocb retry method (already setup for the |
| * iocb on initial submission) for operation specific |
| * handling, but takes care of most of common retry |
| * execution details for a given iocb. The retry method |
| * needs to be non-blocking as far as possible, to avoid |
| * holding up other iocbs waiting to be serviced by the |
| * retry kernel thread. |
| * |
| * The trickier parts in this code have to do with |
| * ensuring that only one retry instance is in progress |
| * for a given iocb at any time. Providing that guarantee |
| * simplifies the coding of individual aio operations as |
| * it avoids various potential races. |
| */ |
| static ssize_t aio_run_iocb(struct kiocb *iocb) |
| { |
| struct kioctx *ctx = iocb->ki_ctx; |
| ssize_t (*retry)(struct kiocb *); |
| ssize_t ret; |
| |
| if (!(retry = iocb->ki_retry)) { |
| printk("aio_run_iocb: iocb->ki_retry = NULL\n"); |
| return 0; |
| } |
| |
| /* |
| * We don't want the next retry iteration for this |
| * operation to start until this one has returned and |
| * updated the iocb state. However, wait_queue functions |
| * can trigger a kick_iocb from interrupt context in the |
| * meantime, indicating that data is available for the next |
| * iteration. We want to remember that and enable the |
| * next retry iteration _after_ we are through with |
| * this one. |
| * |
| * So, in order to be able to register a "kick", but |
| * prevent it from being queued now, we clear the kick |
| * flag, but make the kick code *think* that the iocb is |
| * still on the run list until we are actually done. |
| * When we are done with this iteration, we check if |
| * the iocb was kicked in the meantime and if so, queue |
| * it up afresh. |
| */ |
| |
| kiocbClearKicked(iocb); |
| |
| /* |
| * This is so that aio_complete knows it doesn't need to |
| * pull the iocb off the run list (We can't just call |
| * INIT_LIST_HEAD because we don't want a kick_iocb to |
| * queue this on the run list yet) |
| */ |
| iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL; |
| spin_unlock_irq(&ctx->ctx_lock); |
| |
| /* Quit retrying if the i/o has been cancelled */ |
| if (kiocbIsCancelled(iocb)) { |
| ret = -EINTR; |
| aio_complete(iocb, ret, 0); |
| /* must not access the iocb after this */ |
| goto out; |
| } |
| |
| /* |
| * Now we are all set to call the retry method in async |
| * context. |
| */ |
| ret = retry(iocb); |
| |
| if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) { |
| /* |
| * There's no easy way to restart the syscall since other AIO's |
| * may be already running. Just fail this IO with EINTR. |
| */ |
| if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR || |
| ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK)) |
| ret = -EINTR; |
| aio_complete(iocb, ret, 0); |
| } |
| out: |
| spin_lock_irq(&ctx->ctx_lock); |
| |
| if (-EIOCBRETRY == ret) { |
| /* |
| * OK, now that we are done with this iteration |
| * and know that there is more left to go, |
| * this is where we let go so that a subsequent |
| * "kick" can start the next iteration |
| */ |
| |
| /* will make __queue_kicked_iocb succeed from here on */ |
| INIT_LIST_HEAD(&iocb->ki_run_list); |
| /* we must queue the next iteration ourselves, if it |
| * has already been kicked */ |
| if (kiocbIsKicked(iocb)) { |
| __queue_kicked_iocb(iocb); |
| |
| /* |
| * __queue_kicked_iocb will always return 1 here, because |
| * iocb->ki_run_list is empty at this point so it should |
| * be safe to unconditionally queue the context into the |
| * work queue. |
| */ |
| aio_queue_work(ctx); |
| } |
| } |
| return ret; |
| } |
| |
| /* |
| * __aio_run_iocbs: |
| * Process all pending retries queued on the ioctx |
| * run list. |
| * Assumes it is operating within the aio issuer's mm |
| * context. |
| */ |
| static int __aio_run_iocbs(struct kioctx *ctx) |
| { |
| struct kiocb *iocb; |
| struct list_head run_list; |
| |
| assert_spin_locked(&ctx->ctx_lock); |
| |
| list_replace_init(&ctx->run_list, &run_list); |
| while (!list_empty(&run_list)) { |
| iocb = list_entry(run_list.next, struct kiocb, |
| ki_run_list); |
| list_del(&iocb->ki_run_list); |
| /* |
| * Hold an extra reference while retrying i/o. |
| */ |
| iocb->ki_users++; /* grab extra reference */ |
| aio_run_iocb(iocb); |
| __aio_put_req(ctx, iocb); |
| } |
| if (!list_empty(&ctx->run_list)) |
| return 1; |
| return 0; |
| } |
| |
| static void aio_queue_work(struct kioctx * ctx) |
| { |
| unsigned long timeout; |
| /* |
| * if someone is waiting, get the work started right |
| * away, otherwise, use a longer delay |
| */ |
| smp_mb(); |
| if (waitqueue_active(&ctx->wait)) |
| timeout = 1; |
| else |
| timeout = HZ/10; |
| queue_delayed_work(aio_wq, &ctx->wq, timeout); |
| } |
| |
| /* |
| * aio_run_all_iocbs: |
| * Process all pending retries queued on the ioctx |
| * run list, and keep running them until the list |
| * stays empty. |
| * Assumes it is operating within the aio issuer's mm context. |
| */ |
| static inline void aio_run_all_iocbs(struct kioctx *ctx) |
| { |
| spin_lock_irq(&ctx->ctx_lock); |
| while (__aio_run_iocbs(ctx)) |
| ; |
| spin_unlock_irq(&ctx->ctx_lock); |
| } |
| |
| /* |
| * aio_kick_handler: |
| * Work queue handler triggered to process pending |
| * retries on an ioctx. Takes on the aio issuer's |
| * mm context before running the iocbs, so that |
| * copy_xxx_user operates on the issuer's address |
| * space. |
| * Run on aiod's context. |
| */ |
| static void aio_kick_handler(struct work_struct *work) |
| { |
| struct kioctx *ctx = container_of(work, struct kioctx, wq.work); |
| mm_segment_t oldfs = get_fs(); |
| struct mm_struct *mm; |
| int requeue; |
| |
| set_fs(USER_DS); |
| use_mm(ctx->mm); |
| spin_lock_irq(&ctx->ctx_lock); |
| requeue =__aio_run_iocbs(ctx); |
| mm = ctx->mm; |
| spin_unlock_irq(&ctx->ctx_lock); |
| unuse_mm(mm); |
| set_fs(oldfs); |
| /* |
| * we're in a worker thread already; no point using non-zero delay |
| */ |
| if (requeue) |
| queue_delayed_work(aio_wq, &ctx->wq, 0); |
| } |
| |
| |
| /* |
| * Called by kick_iocb to queue the kiocb for retry |
| * and if required activate the aio work queue to process |
| * it |
| */ |
| static void try_queue_kicked_iocb(struct kiocb *iocb) |
| { |
| struct kioctx *ctx = iocb->ki_ctx; |
| unsigned long flags; |
| int run = 0; |
| |
| spin_lock_irqsave(&ctx->ctx_lock, flags); |
| /* set this inside the lock so that we can't race with aio_run_iocb() |
| * testing it and putting the iocb on the run list under the lock */ |
| if (!kiocbTryKick(iocb)) |
| run = __queue_kicked_iocb(iocb); |
| spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
| if (run) |
| aio_queue_work(ctx); |
| } |
| |
| /* |
| * kick_iocb: |
| * Called typically from a wait queue callback context |
| * to trigger a retry of the iocb. |
| * The retry is usually executed by aio workqueue |
| * threads (See aio_kick_handler). |
| */ |
| void kick_iocb(struct kiocb *iocb) |
| { |
| /* sync iocbs are easy: they can only ever be executing from a |
| * single context. */ |
| if (is_sync_kiocb(iocb)) { |
| kiocbSetKicked(iocb); |
| wake_up_process(iocb->ki_obj.tsk); |
| return; |
| } |
| |
| try_queue_kicked_iocb(iocb); |
| } |
| EXPORT_SYMBOL(kick_iocb); |
| |
| /* aio_complete |
| * Called when the io request on the given iocb is complete. |
| * Returns true if this is the last user of the request. The |
| * only other user of the request can be the cancellation code. |
| */ |
| int aio_complete(struct kiocb *iocb, long res, long res2) |
| { |
| struct kioctx *ctx = iocb->ki_ctx; |
| struct aio_ring_info *info; |
| struct aio_ring *ring; |
| struct io_event *event; |
| unsigned long flags; |
| unsigned long tail; |
| int ret; |
| |
| /* |
| * Special case handling for sync iocbs: |
| * - events go directly into the iocb for fast handling |
| * - the sync task with the iocb in its stack holds the single iocb |
| * ref, no other paths have a way to get another ref |
| * - the sync task helpfully left a reference to itself in the iocb |
| */ |
| if (is_sync_kiocb(iocb)) { |
| BUG_ON(iocb->ki_users != 1); |
| iocb->ki_user_data = res; |
| iocb->ki_users = 0; |
| wake_up_process(iocb->ki_obj.tsk); |
| return 1; |
| } |
| |
| info = &ctx->ring_info; |
| |
| /* add a completion event to the ring buffer. |
| * must be done holding ctx->ctx_lock to prevent |
| * other code from messing with the tail |
| * pointer since we might be called from irq |
| * context. |
| */ |
| spin_lock_irqsave(&ctx->ctx_lock, flags); |
| |
| if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list)) |
| list_del_init(&iocb->ki_run_list); |
| |
| /* |
| * cancelled requests don't get events, userland was given one |
| * when the event got cancelled. |
| */ |
| if (kiocbIsCancelled(iocb)) |
| goto put_rq; |
| |
| ring = kmap_atomic(info->ring_pages[0]); |
| |
| tail = info->tail; |
| event = aio_ring_event(info, tail); |
| if (++tail >= info->nr) |
| tail = 0; |
| |
| event->obj = (u64)(unsigned long)iocb->ki_obj.user; |
| event->data = iocb->ki_user_data; |
| event->res = res; |
| event->res2 = res2; |
| |
| dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n", |
| ctx, tail, iocb, iocb->ki_obj.user, 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 */ |
| |
| info->tail = tail; |
| ring->tail = tail; |
| |
| put_aio_ring_event(event); |
| kunmap_atomic(ring); |
| |
| pr_debug("added to ring %p at [%lu]\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 != NULL) |
| eventfd_signal(iocb->ki_eventfd, 1); |
| |
| put_rq: |
| /* everything turned out well, dispose of the aiocb. */ |
| ret = __aio_put_req(ctx, iocb); |
| |
| /* |
| * 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); |
| |
| spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
| return ret; |
| } |
| EXPORT_SYMBOL(aio_complete); |
| |
| /* aio_read_evt |
| * Pull an event off of the ioctx's event ring. Returns the number of |
| * events fetched (0 or 1 ;-) |
| * FIXME: make this use cmpxchg. |
| * TODO: make the ringbuffer user mmap()able (requires FIXME). |
| */ |
| static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent) |
| { |
| struct aio_ring_info *info = &ioctx->ring_info; |
| struct aio_ring *ring; |
| unsigned long head; |
| int ret = 0; |
| |
| ring = kmap_atomic(info->ring_pages[0]); |
| dprintk("in aio_read_evt h%lu t%lu m%lu\n", |
| (unsigned long)ring->head, (unsigned long)ring->tail, |
| (unsigned long)ring->nr); |
| |
| if (ring->head == ring->tail) |
| goto out; |
| |
| spin_lock(&info->ring_lock); |
| |
| head = ring->head % info->nr; |
| if (head != ring->tail) { |
| struct io_event *evp = aio_ring_event(info, head); |
| *ent = *evp; |
| head = (head + 1) % info->nr; |
| smp_mb(); /* finish reading the event before updatng the head */ |
| ring->head = head; |
| ret = 1; |
| put_aio_ring_event(evp); |
| } |
| spin_unlock(&info->ring_lock); |
| |
| out: |
| kunmap_atomic(ring); |
| dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret, |
| (unsigned long)ring->head, (unsigned long)ring->tail); |
| return ret; |
| } |
| |
| struct aio_timeout { |
| struct timer_list timer; |
| int timed_out; |
| struct task_struct *p; |
| }; |
| |
| static void timeout_func(unsigned long data) |
| { |
| struct aio_timeout *to = (struct aio_timeout *)data; |
| |
| to->timed_out = 1; |
| wake_up_process(to->p); |
| } |
| |
| static inline void init_timeout(struct aio_timeout *to) |
| { |
| setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to); |
| to->timed_out = 0; |
| to->p = current; |
| } |
| |
| static inline void set_timeout(long start_jiffies, struct aio_timeout *to, |
| const struct timespec *ts) |
| { |
| to->timer.expires = start_jiffies + timespec_to_jiffies(ts); |
| if (time_after(to->timer.expires, jiffies)) |
| add_timer(&to->timer); |
| else |
| to->timed_out = 1; |
| } |
| |
| static inline void clear_timeout(struct aio_timeout *to) |
| { |
| del_singleshot_timer_sync(&to->timer); |
| } |
| |
| static int read_events(struct kioctx *ctx, |
| long min_nr, long nr, |
| struct io_event __user *event, |
| struct timespec __user *timeout) |
| { |
| long start_jiffies = jiffies; |
| struct task_struct *tsk = current; |
| DECLARE_WAITQUEUE(wait, tsk); |
| int ret; |
| int i = 0; |
| struct io_event ent; |
| struct aio_timeout to; |
| int retry = 0; |
| |
| /* needed to zero any padding within an entry (there shouldn't be |
| * any, but C is fun! |
| */ |
| memset(&ent, 0, sizeof(ent)); |
| retry: |
| ret = 0; |
| while (likely(i < nr)) { |
| ret = aio_read_evt(ctx, &ent); |
| if (unlikely(ret <= 0)) |
| break; |
| |
| dprintk("read event: %Lx %Lx %Lx %Lx\n", |
| ent.data, ent.obj, ent.res, ent.res2); |
| |
| /* Could we split the check in two? */ |
| ret = -EFAULT; |
| if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
| dprintk("aio: lost an event due to EFAULT.\n"); |
| break; |
| } |
| ret = 0; |
| |
| /* Good, event copied to userland, update counts. */ |
| event ++; |
| i ++; |
| } |
| |
| if (min_nr <= i) |
| return i; |
| if (ret) |
| return ret; |
| |
| /* End fast path */ |
| |
| /* racey check, but it gets redone */ |
| if (!retry && unlikely(!list_empty(&ctx->run_list))) { |
| retry = 1; |
| aio_run_all_iocbs(ctx); |
| goto retry; |
| } |
| |
| init_timeout(&to); |
| if (timeout) { |
| struct timespec ts; |
| ret = -EFAULT; |
| if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) |
| goto out; |
| |
| set_timeout(start_jiffies, &to, &ts); |
| } |
| |
| while (likely(i < nr)) { |
| add_wait_queue_exclusive(&ctx->wait, &wait); |
| do { |
| set_task_state(tsk, TASK_INTERRUPTIBLE); |
| ret = aio_read_evt(ctx, &ent); |
| if (ret) |
| break; |
| if (min_nr <= i) |
| break; |
| if (unlikely(ctx->dead)) { |
| ret = -EINVAL; |
| break; |
| } |
| if (to.timed_out) /* Only check after read evt */ |
| break; |
| /* Try to only show up in io wait if there are ops |
| * in flight */ |
| if (ctx->reqs_active) |
| io_schedule(); |
| else |
| schedule(); |
| if (signal_pending(tsk)) { |
| ret = -EINTR; |
| break; |
| } |
| /*ret = aio_read_evt(ctx, &ent);*/ |
| } while (1) ; |
| |
| set_task_state(tsk, TASK_RUNNING); |
| remove_wait_queue(&ctx->wait, &wait); |
| |
| if (unlikely(ret <= 0)) |
| break; |
| |
| ret = -EFAULT; |
| if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
| dprintk("aio: lost an event due to EFAULT.\n"); |
| break; |
| } |
| |
| /* Good, event copied to userland, update counts. */ |
| event ++; |
| i ++; |
| } |
| |
| if (timeout) |
| clear_timeout(&to); |
| out: |
| destroy_timer_on_stack(&to.timer); |
| return i ? i : ret; |
| } |
| |
| /* Take an ioctx and remove it from the list of ioctx's. Protects |
| * against races with itself via ->dead. |
| */ |
| static void io_destroy(struct kioctx *ioctx) |
| { |
| struct mm_struct *mm = current->mm; |
| int was_dead; |
| |
| /* delete the entry from the list is someone else hasn't already */ |
| spin_lock(&mm->ioctx_lock); |
| was_dead = ioctx->dead; |
| ioctx->dead = 1; |
| hlist_del_rcu(&ioctx->list); |
| spin_unlock(&mm->ioctx_lock); |
| |
| dprintk("aio_release(%p)\n", ioctx); |
| if (likely(!was_dead)) |
| put_ioctx(ioctx); /* twice for the list */ |
| |
| kill_ctx(ioctx); |
| |
| /* |
| * Wake up any waiters. The setting of ctx->dead must be seen |
| * by other CPUs at this point. Right now, we rely on the |
| * locking done by the above calls to ensure this consistency. |
| */ |
| wake_up_all(&ioctx->wait); |
| } |
| |
| /* 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: io_setup: 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) |
| io_destroy(ioctx); |
| put_ioctx(ioctx); |
| } |
| |
| out: |
| return ret; |
| } |
| |
| /* 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)) { |
| io_destroy(ioctx); |
| put_ioctx(ioctx); |
| return 0; |
| } |
| pr_debug("EINVAL: io_destroy: invalid context id\n"); |
| return -EINVAL; |
| } |
| |
| static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret) |
| { |
| struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg]; |
| |
| BUG_ON(ret <= 0); |
| |
| while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) { |
| ssize_t this = min((ssize_t)iov->iov_len, ret); |
| iov->iov_base += this; |
| iov->iov_len -= this; |
| iocb->ki_left -= this; |
| ret -= this; |
| if (iov->iov_len == 0) { |
| iocb->ki_cur_seg++; |
| iov++; |
| } |
| } |
| |
| /* the caller should not have done more io than what fit in |
| * the remaining iovecs */ |
| BUG_ON(ret > 0 && iocb->ki_left == 0); |
| } |
| |
| static ssize_t aio_rw_vect_retry(struct kiocb *iocb) |
| { |
| struct file *file = iocb->ki_filp; |
| struct address_space *mapping = file->f_mapping; |
| struct inode *inode = mapping->host; |
| ssize_t (*rw_op)(struct kiocb *, const struct iovec *, |
| unsigned long, loff_t); |
| ssize_t ret = 0; |
| unsigned short opcode; |
| |
| if ((iocb->ki_opcode == IOCB_CMD_PREADV) || |
| (iocb->ki_opcode == IOCB_CMD_PREAD)) { |
| rw_op = file->f_op->aio_read; |
| opcode = IOCB_CMD_PREADV; |
| } else { |
| rw_op = file->f_op->aio_write; |
| opcode = IOCB_CMD_PWRITEV; |
| } |
| |
| /* This matches the pread()/pwrite() logic */ |
| if (iocb->ki_pos < 0) |
| return -EINVAL; |
| |
| do { |
| ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg], |
| iocb->ki_nr_segs - iocb->ki_cur_seg, |
| iocb->ki_pos); |
| if (ret > 0) |
| aio_advance_iovec(iocb, ret); |
| |
| /* retry all partial writes. retry partial reads as long as its a |
| * regular file. */ |
| } while (ret > 0 && iocb->ki_left > 0 && |
| (opcode == IOCB_CMD_PWRITEV || |
| (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode)))); |
| |
| /* This means we must have transferred all that we could */ |
| /* No need to retry anymore */ |
| if ((ret == 0) || (iocb->ki_left == 0)) |
| ret = iocb->ki_nbytes - iocb->ki_left; |
| |
| /* If we managed to write some out we return that, rather than |
| * the eventual error. */ |
| if (opcode == IOCB_CMD_PWRITEV |
| && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY |
| && iocb->ki_nbytes - iocb->ki_left) |
| ret = iocb->ki_nbytes - iocb->ki_left; |
| |
| return ret; |
| } |
| |
| static ssize_t aio_fdsync(struct kiocb *iocb) |
| { |
| struct file *file = iocb->ki_filp; |
| ssize_t ret = -EINVAL; |
| |
| if (file->f_op->aio_fsync) |
| ret = file->f_op->aio_fsync(iocb, 1); |
| return ret; |
| } |
| |
| static ssize_t aio_fsync(struct kiocb *iocb) |
| { |
| struct file *file = iocb->ki_filp; |
| ssize_t ret = -EINVAL; |
| |
| if (file->f_op->aio_fsync) |
| ret = file->f_op->aio_fsync(iocb, 0); |
| return ret; |
| } |
| |
| static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat) |
| { |
| ssize_t ret; |
| |
| #ifdef CONFIG_COMPAT |
| if (compat) |
| ret = compat_rw_copy_check_uvector(type, |
| (struct compat_iovec __user *)kiocb->ki_buf, |
| kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, |
| &kiocb->ki_iovec, 1); |
| else |
| #endif |
| ret = rw_copy_check_uvector(type, |
| (struct iovec __user *)kiocb->ki_buf, |
| kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, |
| &kiocb->ki_iovec, 1); |
| if (ret < 0) |
| goto out; |
| |
| kiocb->ki_nr_segs = kiocb->ki_nbytes; |
| kiocb->ki_cur_seg = 0; |
| /* ki_nbytes/left now reflect bytes instead of segs */ |
| kiocb->ki_nbytes = ret; |
| kiocb->ki_left = ret; |
| |
| ret = 0; |
| out: |
| return ret; |
| } |
| |
| static ssize_t aio_setup_single_vector(struct kiocb *kiocb) |
| { |
| kiocb->ki_iovec = &kiocb->ki_inline_vec; |
| kiocb->ki_iovec->iov_base = kiocb->ki_buf; |
| kiocb->ki_iovec->iov_len = kiocb->ki_left; |
| kiocb->ki_nr_segs = 1; |
| kiocb->ki_cur_seg = 0; |
| return 0; |
| } |
| |
| /* |
| * aio_setup_iocb: |
| * Performs the initial checks and aio retry method |
| * setup for the kiocb at the time of io submission. |
| */ |
| static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat) |
| { |
| struct file *file = kiocb->ki_filp; |
| ssize_t ret = 0; |
| |
| switch (kiocb->ki_opcode) { |
| case IOCB_CMD_PREAD: |
| ret = -EBADF; |
| if (unlikely(!(file->f_mode & FMODE_READ))) |
| break; |
| ret = -EFAULT; |
| if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf, |
| kiocb->ki_left))) |
| break; |
| ret = security_file_permission(file, MAY_READ); |
| if (unlikely(ret)) |
| break; |
| ret = aio_setup_single_vector(kiocb); |
| if (ret) |
| break; |
| ret = -EINVAL; |
| if (file->f_op->aio_read) |
| kiocb->ki_retry = aio_rw_vect_retry; |
| break; |
| case IOCB_CMD_PWRITE: |
| ret = -EBADF; |
| if (unlikely(!(file->f_mode & FMODE_WRITE))) |
| break; |
| ret = -EFAULT; |
| if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf, |
| kiocb->ki_left))) |
| break; |
| ret = security_file_permission(file, MAY_WRITE); |
| if (unlikely(ret)) |
| break; |
| ret = aio_setup_single_vector(kiocb); |
| if (ret) |
| break; |
| ret = -EINVAL; |
| if (file->f_op->aio_write) |
| kiocb->ki_retry = aio_rw_vect_retry; |
| break; |
| case IOCB_CMD_PREADV: |
| ret = -EBADF; |
| if (unlikely(!(file->f_mode & FMODE_READ))) |
| break; |
| ret = security_file_permission(file, MAY_READ); |
| if (unlikely(ret)) |
| break; |
| ret = aio_setup_vectored_rw(READ, kiocb, compat); |
| if (ret) |
| break; |
| ret = -EINVAL; |
| if (file->f_op->aio_read) |
| kiocb->ki_retry = aio_rw_vect_retry; |
| break; |
| case IOCB_CMD_PWRITEV: |
| ret = -EBADF; |
| if (unlikely(!(file->f_mode & FMODE_WRITE))) |
| break; |
| ret = security_file_permission(file, MAY_WRITE); |
| if (unlikely(ret)) |
| break; |
| ret = aio_setup_vectored_rw(WRITE, kiocb, compat); |
| if (ret) |
| break; |
| ret = -EINVAL; |
| if (file->f_op->aio_write) |
| kiocb->ki_retry = aio_rw_vect_retry; |
| break; |
| case IOCB_CMD_FDSYNC: |
| ret = -EINVAL; |
| if (file->f_op->aio_fsync) |
| kiocb->ki_retry = aio_fdsync; |
| break; |
| case IOCB_CMD_FSYNC: |
| ret = -EINVAL; |
| if (file->f_op->aio_fsync) |
| kiocb->ki_retry = aio_fsync; |
| break; |
| default: |
| dprintk("EINVAL: io_submit: no operation provided\n"); |
| ret = -EINVAL; |
| } |
| |
| if (!kiocb->ki_retry) |
| return ret; |
| |
| return 0; |
| } |
| |
| static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
| struct iocb *iocb, struct kiocb_batch *batch, |
| bool compat) |
| { |
| struct kiocb *req; |
| struct file *file; |
| ssize_t ret; |
| |
| /* enforce forwards compatibility on users */ |
| if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { |
| pr_debug("EINVAL: io_submit: 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: io_submit: overflow check\n"); |
| return -EINVAL; |
| } |
| |
| file = fget(iocb->aio_fildes); |
| if (unlikely(!file)) |
| return -EBADF; |
| |
| req = aio_get_req(ctx, batch); /* returns with 2 references to req */ |
| if (unlikely(!req)) { |
| fput(file); |
| return -EAGAIN; |
| } |
| req->ki_filp = file; |
| 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(req->ki_key, &user_iocb->aio_key); |
| if (unlikely(ret)) { |
| dprintk("EFAULT: aio_key\n"); |
| goto out_put_req; |
| } |
| |
| req->ki_obj.user = user_iocb; |
| req->ki_user_data = iocb->aio_data; |
| req->ki_pos = iocb->aio_offset; |
| |
| req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf; |
| req->ki_left = req->ki_nbytes = iocb->aio_nbytes; |
| req->ki_opcode = iocb->aio_lio_opcode; |
| |
| ret = aio_setup_iocb(req, compat); |
| |
| if (ret) |
| goto out_put_req; |
| |
| spin_lock_irq(&ctx->ctx_lock); |
| /* |
| * We could have raced with io_destroy() and are currently holding a |
| * reference to ctx which should be destroyed. We cannot submit IO |
| * since ctx gets freed as soon as io_submit() puts its reference. The |
| * check here is reliable: io_destroy() sets ctx->dead before waiting |
| * for outstanding IO and the barrier between these two is realized by |
| * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we |
| * increment ctx->reqs_active before checking for ctx->dead and the |
| * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we |
| * don't see ctx->dead set here, io_destroy() waits for our IO to |
| * finish. |
| */ |
| if (ctx->dead) { |
| spin_unlock_irq(&ctx->ctx_lock); |
| ret = -EINVAL; |
| goto out_put_req; |
| } |
| aio_run_iocb(req); |
| if (!list_empty(&ctx->run_list)) { |
| /* drain the run list */ |
| while (__aio_run_iocbs(ctx)) |
| ; |
| } |
| spin_unlock_irq(&ctx->ctx_lock); |
| |
| aio_put_req(req); /* drop extra ref to req */ |
| return 0; |
| |
| out_put_req: |
| aio_put_req(req); /* drop extra ref to req */ |
| aio_put_req(req); /* drop i/o ref to req */ |
| return ret; |
| } |
| |
| long do_io_submit(aio_context_t ctx_id, long nr, |
| struct iocb __user *__user *iocbpp, bool compat) |
| { |
| struct kioctx *ctx; |
| long ret = 0; |
| int i = 0; |
| struct blk_plug plug; |
| struct kiocb_batch batch; |
| |
| if (unlikely(nr < 0)) |
| return -EINVAL; |
| |
| if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) |
| nr = LONG_MAX/sizeof(*iocbpp); |
| |
| if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
| return -EFAULT; |
| |
| ctx = lookup_ioctx(ctx_id); |
| if (unlikely(!ctx)) { |
| pr_debug("EINVAL: io_submit: invalid context id\n"); |
| return -EINVAL; |
| } |
| |
| kiocb_batch_init(&batch, nr); |
| |
| blk_start_plug(&plug); |
| |
| /* |
| * AKPM: should this return a partial result if some of the IOs were |
| * successfully submitted? |
| */ |
| for (i=0; i<nr; i++) { |
| struct iocb __user *user_iocb; |
| struct iocb tmp; |
| |
| if (unlikely(__get_user(user_iocb, iocbpp + i))) { |
| ret = -EFAULT; |
| break; |
| } |
| |
| if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { |
| ret = -EFAULT; |
| break; |
| } |
| |
| ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat); |
| if (ret) |
| break; |
| } |
| blk_finish_plug(&plug); |
| |
| kiocb_batch_free(ctx, &batch); |
| put_ioctx(ctx); |
| return i ? i : 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) |
| { |
| return do_io_submit(ctx_id, nr, iocbpp, 0); |
| } |
| |
| /* lookup_kiocb |
| * Finds a given iocb for cancellation. |
| */ |
| static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, |
| u32 key) |
| { |
| struct list_head *pos; |
| |
| assert_spin_locked(&ctx->ctx_lock); |
| |
| /* TODO: use a hash or array, this sucks. */ |
| list_for_each(pos, &ctx->active_reqs) { |
| struct kiocb *kiocb = list_kiocb(pos); |
| if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key) |
| 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) |
| { |
| int (*cancel)(struct kiocb *iocb, struct io_event *res); |
| struct kioctx *ctx; |
| struct kiocb *kiocb; |
| u32 key; |
| int ret; |
| |
| ret = get_user(key, &iocb->aio_key); |
| if (unlikely(ret)) |
| return -EFAULT; |
| |
| ctx = lookup_ioctx(ctx_id); |
| if (unlikely(!ctx)) |
| return -EINVAL; |
| |
| spin_lock_irq(&ctx->ctx_lock); |
| ret = -EAGAIN; |
| kiocb = lookup_kiocb(ctx, iocb, key); |
| if (kiocb && kiocb->ki_cancel) { |
| cancel = kiocb->ki_cancel; |
| kiocb->ki_users ++; |
| kiocbSetCancelled(kiocb); |
| } else |
| cancel = NULL; |
| spin_unlock_irq(&ctx->ctx_lock); |
| |
| if (NULL != cancel) { |
| struct io_event tmp; |
| pr_debug("calling cancel\n"); |
| memset(&tmp, 0, sizeof(tmp)); |
| tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user; |
| tmp.data = kiocb->ki_user_data; |
| ret = cancel(kiocb, &tmp); |
| if (!ret) { |
| /* Cancellation succeeded -- copy the result |
| * into the user's buffer. |
| */ |
| if (copy_to_user(result, &tmp, sizeof(tmp))) |
| ret = -EFAULT; |
| } |
| } else |
| ret = -EINVAL; |
| |
| put_ioctx(ctx); |
| |
| 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 and will be updated if not NULL and the |
| * operation blocks. 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 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, timeout); |
| put_ioctx(ioctx); |
| } |
| |
| asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout); |
| return ret; |
| } |