diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/aio.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/aio.c | 1861 |
1 files changed, 0 insertions, 1861 deletions
diff --git a/ANDROID_3.4.5/fs/aio.c b/ANDROID_3.4.5/fs/aio.c deleted file mode 100644 index e7f2fad7..00000000 --- a/ANDROID_3.4.5/fs/aio.c +++ /dev/null @@ -1,1861 +0,0 @@ -/* - * 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) { - BUG_ON(ctx->mm != current->mm); - vm_munmap(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); - /* - * We don't need to bother with munmap() here - - * exit_mmap(mm) is coming and it'll unmap everything. - * Since aio_free_ring() uses non-zero ->mmap_size - * as indicator that it needs to unmap the area, - * just set it to 0; aio_free_ring() is the only - * place that uses ->mmap_size, so it's safe. - * That way we get all munmap done to current->mm - - * all other callers have ctx->mm == current->mm. - */ - ctx->ring_info.mmap_size = 0; - 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; - - ret = rw_verify_area(type, kiocb->ki_filp, &kiocb->ki_pos, ret); - 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(int type, struct file * file, struct kiocb *kiocb) -{ - int bytes; - - bytes = rw_verify_area(type, file, &kiocb->ki_pos, kiocb->ki_left); - if (bytes < 0) - return bytes; - - kiocb->ki_iovec = &kiocb->ki_inline_vec; - kiocb->ki_iovec->iov_base = kiocb->ki_buf; - kiocb->ki_iovec->iov_len = bytes; - 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 = aio_setup_single_vector(READ, file, 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 = aio_setup_single_vector(WRITE, file, 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 = 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 = 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; -} |