diff options
Diffstat (limited to 'fs/aio.c')
| -rw-r--r-- | fs/aio.c | 1729 |
1 files changed, 1729 insertions, 0 deletions
diff --git a/fs/aio.c b/fs/aio.c new file mode 100644 index 00000000000..d06a266769b --- /dev/null +++ b/fs/aio.c @@ -0,0 +1,1729 @@ +/* + * 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/module.h> +#include <linux/syscalls.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/slab.h> +#include <linux/timer.h> +#include <linux/aio.h> +#include <linux/highmem.h> +#include <linux/workqueue.h> +#include <linux/security.h> + +#include <asm/kmap_types.h> +#include <asm/uaccess.h> +#include <asm/mmu_context.h> + +#if DEBUG > 1 +#define dprintk printk +#else +#define dprintk(x...) do { ; } while (0) +#endif + +long aio_run = 0; /* for testing only */ +long aio_wakeups = 0; /* for testing only */ + +/*------ sysctl variables----*/ +atomic_t aio_nr = ATOMIC_INIT(0); /* current system wide number of aio requests */ +unsigned aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ +/*----end sysctl variables---*/ + +static kmem_cache_t *kiocb_cachep; +static kmem_cache_t *kioctx_cachep; + +static struct workqueue_struct *aio_wq; + +/* Used for rare fput completion. */ +static void aio_fput_routine(void *); +static DECLARE_WORK(fput_work, aio_fput_routine, NULL); + +static DEFINE_SPINLOCK(fput_lock); +LIST_HEAD(fput_head); + +static void aio_kick_handler(void *); + +/* 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_create("kiocb", sizeof(struct kiocb), + 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); + kioctx_cachep = kmem_cache_create("kioctx", sizeof(struct kioctx), + 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); + + aio_wq = create_workqueue("aio"); + + pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page)); + + return 0; +} + +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) { + down_write(&ctx->mm->mmap_sem); + do_munmap(ctx->mm, info->mmap_base, info->mmap_size); + up_write(&ctx->mm->mmap_sem); + } + + 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 = kmalloc(sizeof(struct page *) * nr_pages, GFP_KERNEL); + if (!info->ring_pages) + return -ENOMEM; + memset(info->ring_pages, 0, sizeof(struct page *) * nr_pages); + } + + 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_ANON|MAP_PRIVATE, + 0); + if (IS_ERR((void *)info->mmap_base)) { + up_write(&ctx->mm->mmap_sem); + printk("mmap err: %ld\n", -info->mmap_base); + 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], KM_USER0); + 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, KM_USER0); + + return 0; +} + + +/* aio_ring_event: returns a pointer to the event at the given index from + * kmap_atomic(, km). 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, km) ({ \ + unsigned pos = (nr) + AIO_EVENTS_OFFSET; \ + struct io_event *__event; \ + __event = kmap_atomic( \ + (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \ + __event += pos % AIO_EVENTS_PER_PAGE; \ + __event; \ +}) + +#define put_aio_ring_event(event, km) do { \ + struct io_event *__event = (event); \ + (void)__event; \ + kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \ +} while(0) + +/* 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; + + /* 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 > aio_max_nr) + return ERR_PTR(-EAGAIN); + + ctx = kmem_cache_alloc(kioctx_cachep, GFP_KERNEL); + if (!ctx) + return ERR_PTR(-ENOMEM); + + memset(ctx, 0, sizeof(*ctx)); + ctx->max_reqs = nr_events; + mm = ctx->mm = current->mm; + atomic_inc(&mm->mm_count); + + atomic_set(&ctx->users, 1); + 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_WORK(&ctx->wq, aio_kick_handler, ctx); + + if (aio_setup_ring(ctx) < 0) + goto out_freectx; + + /* limit the number of system wide aios */ + atomic_add(ctx->max_reqs, &aio_nr); /* undone by __put_ioctx */ + if (unlikely(atomic_read(&aio_nr) > aio_max_nr)) + goto out_cleanup; + + /* now link into global list. kludge. FIXME */ + write_lock(&mm->ioctx_list_lock); + ctx->next = mm->ioctx_list; + mm->ioctx_list = ctx; + write_unlock(&mm->ioctx_list_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: + atomic_sub(ctx->max_reqs, &aio_nr); + ctx->max_reqs = 0; /* prevent __put_ioctx from sub'ing aio_nr */ + __put_ioctx(ctx); + return ERR_PTR(-EAGAIN); + +out_freectx: + mmdrop(mm); + kmem_cache_free(kioctx_cachep, ctx); + ctx = ERR_PTR(-ENOMEM); + + dprintk("aio: error allocating ioctx %p\n", ctx); + return ctx; +} + +/* aio_cancel_all + * 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 aio_cancel_all(struct kioctx *ctx) +{ + int (*cancel)(struct kiocb *, struct io_event *); + 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); + } + } + spin_unlock_irq(&ctx->ctx_lock); +} + +void wait_for_all_aios(struct kioctx *ctx) +{ + struct task_struct *tsk = current; + DECLARE_WAITQUEUE(wait, tsk); + + if (!ctx->reqs_active) + return; + + add_wait_queue(&ctx->wait, &wait); + set_task_state(tsk, TASK_UNINTERRUPTIBLE); + while (ctx->reqs_active) { + schedule(); + set_task_state(tsk, TASK_UNINTERRUPTIBLE); + } + __set_task_state(tsk, TASK_RUNNING); + remove_wait_queue(&ctx->wait, &wait); +} + +/* wait_on_sync_kiocb: + * Waits on the given sync kiocb to complete. + */ +ssize_t fastcall wait_on_sync_kiocb(struct kiocb *iocb) +{ + while (iocb->ki_users) { + set_current_state(TASK_UNINTERRUPTIBLE); + if (!iocb->ki_users) + break; + schedule(); + } + __set_current_state(TASK_RUNNING); + return iocb->ki_user_data; +} + +/* 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 fastcall exit_aio(struct mm_struct *mm) +{ + struct kioctx *ctx = mm->ioctx_list; + mm->ioctx_list = NULL; + while (ctx) { + struct kioctx *next = ctx->next; + ctx->next = NULL; + aio_cancel_all(ctx); + + wait_for_all_aios(ctx); + /* + * this is an overkill, but ensures we don't leave + * the ctx on the aio_wq + */ + flush_workqueue(aio_wq); + + 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); + ctx = next; + } +} + +/* __put_ioctx + * Called when the last user of an aio context has gone away, + * and the struct needs to be freed. + */ +void fastcall __put_ioctx(struct kioctx *ctx) +{ + unsigned nr_events = ctx->max_reqs; + + if (unlikely(ctx->reqs_active)) + BUG(); + + cancel_delayed_work(&ctx->wq); + flush_workqueue(aio_wq); + aio_free_ring(ctx); + mmdrop(ctx->mm); + ctx->mm = NULL; + pr_debug("__put_ioctx: freeing %p\n", ctx); + kmem_cache_free(kioctx_cachep, ctx); + + atomic_sub(nr_events, &aio_nr); +} + +/* 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 *FASTCALL(__aio_get_req(struct kioctx *ctx)); +static struct kiocb fastcall *__aio_get_req(struct kioctx *ctx) +{ + struct kiocb *req = NULL; + struct aio_ring *ring; + int okay = 0; + + req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); + if (unlikely(!req)) + return NULL; + + req->ki_flags = 1 << KIF_LOCKED; + req->ki_users = 2; + req->ki_key = 0; + req->ki_ctx = ctx; + req->ki_cancel = NULL; + req->ki_retry = NULL; + req->ki_obj.user = NULL; + req->ki_dtor = NULL; + req->private = NULL; + INIT_LIST_HEAD(&req->ki_run_list); + + /* Check if the completion queue has enough free space to + * accept an event from this io. + */ + spin_lock_irq(&ctx->ctx_lock); + ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0); + if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) { + list_add(&req->ki_list, &ctx->active_reqs); + get_ioctx(ctx); + ctx->reqs_active++; + okay = 1; + } + kunmap_atomic(ring, KM_USER0); + spin_unlock_irq(&ctx->ctx_lock); + + if (!okay) { + kmem_cache_free(kiocb_cachep, req); + req = NULL; + } + + return req; +} + +static inline struct kiocb *aio_get_req(struct kioctx *ctx) +{ + struct kiocb *req; + /* Handle a potential starvation case -- should be exceedingly rare as + * requests will be stuck on fput_head only if the aio_fput_routine is + * delayed and the requests were the last user of the struct file. + */ + req = __aio_get_req(ctx); + if (unlikely(NULL == req)) { + aio_fput_routine(NULL); + req = __aio_get_req(ctx); + } + return req; +} + +static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) +{ + if (req->ki_dtor) + req->ki_dtor(req); + req->ki_ctx = NULL; + req->ki_filp = NULL; + req->ki_obj.user = NULL; + req->ki_dtor = NULL; + req->private = NULL; + kmem_cache_free(kiocb_cachep, req); + ctx->reqs_active--; + + if (unlikely(!ctx->reqs_active && ctx->dead)) + wake_up(&ctx->wait); +} + +static void aio_fput_routine(void *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 */ + __fput(req->ki_filp); + + /* Link the iocb into the context's free list */ + spin_lock_irq(&ctx->ctx_lock); + really_put_req(ctx, req); + spin_unlock_irq(&ctx->ctx_lock); + + put_ioctx(ctx); + 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=%d\n", + req, atomic_read(&req->ki_filp->f_count)); + + req->ki_users --; + if (unlikely(req->ki_users < 0)) + BUG(); + if (likely(req->ki_users)) + return 0; + list_del(&req->ki_list); /* remove from active_reqs */ + req->ki_cancel = NULL; + req->ki_retry = NULL; + + /* Must be done under the lock to serialise against cancellation. + * Call this aio_fput as it duplicates fput via the fput_work. + */ + if (unlikely(atomic_dec_and_test(&req->ki_filp->f_count))) { + get_ioctx(ctx); + spin_lock(&fput_lock); + list_add(&req->ki_list, &fput_head); + spin_unlock(&fput_lock); + queue_work(aio_wq, &fput_work); + } else + 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 fastcall 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); + if (ret) + put_ioctx(ctx); + return ret; +} + +/* Lookup an ioctx id. ioctx_list is lockless for reads. + * FIXME: this is O(n) and is only suitable for development. + */ +struct kioctx *lookup_ioctx(unsigned long ctx_id) +{ + struct kioctx *ioctx; + struct mm_struct *mm; + + mm = current->mm; + read_lock(&mm->ioctx_list_lock); + for (ioctx = mm->ioctx_list; ioctx; ioctx = ioctx->next) + if (likely(ioctx->user_id == ctx_id && !ioctx->dead)) { + get_ioctx(ioctx); + break; + } + read_unlock(&mm->ioctx_list_lock); + + return ioctx; +} + +/* + * use_mm + * Makes the calling kernel thread take on the specified + * mm context. + * Called by the retry thread execute retries within the + * iocb issuer's mm context, so that copy_from/to_user + * operations work seamlessly for aio. + * (Note: this routine is intended to be called only + * from a kernel thread context) + */ +static void use_mm(struct mm_struct *mm) +{ + struct mm_struct *active_mm; + struct task_struct *tsk = current; + + task_lock(tsk); + tsk->flags |= PF_BORROWED_MM; + active_mm = tsk->active_mm; + atomic_inc(&mm->mm_count); + tsk->mm = mm; + tsk->active_mm = mm; + activate_mm(active_mm, mm); + task_unlock(tsk); + + mmdrop(active_mm); +} + +/* + * unuse_mm + * Reverses the effect of use_mm, i.e. releases the + * specified mm context which was earlier taken on + * by the calling kernel thread + * (Note: this routine is intended to be called only + * from a kernel thread context) + * + * Comments: Called with ctx->ctx_lock held. This nests + * task_lock instead ctx_lock. + */ +void unuse_mm(struct mm_struct *mm) +{ + struct task_struct *tsk = current; + + task_lock(tsk); + tsk->flags &= ~PF_BORROWED_MM; + tsk->mm = NULL; + /* active_mm is still 'mm' */ + enter_lazy_tlb(mm, tsk); + task_unlock(tsk); +} + +/* + * 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. + * + * Should be called with the spin lock iocb->ki_ctx->ctx_lock + * held + */ +static inline int __queue_kicked_iocb(struct kiocb *iocb) +{ + struct kioctx *ctx = iocb->ki_ctx; + + if (list_empty(&iocb->ki_run_list)) { + list_add_tail(&iocb->ki_run_list, + &ctx->run_list); + iocb->ki_queued++; + 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 reaquired + * 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 (iocb->ki_retried++ > 1024*1024) { + printk("Maximal retry count. Bytes done %Zd\n", + iocb->ki_nbytes - iocb->ki_left); + return -EAGAIN; + } + + if (!(iocb->ki_retried & 0xff)) { + pr_debug("%ld retry: %d of %d (kick %ld, Q %ld run %ld, wake %ld)\n", + iocb->ki_retried, + iocb->ki_nbytes - iocb->ki_left, iocb->ki_nbytes, + iocb->ki_kicked, iocb->ki_queued, aio_run, aio_wakeups); + } + + 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. By setting this thread's io_wait context + * to point to the wait queue entry inside the currently + * running iocb for the duration of the retry, we ensure + * that async notification wakeups are queued by the + * operation instead of blocking waits, and when notified, + * cause the iocb to be kicked for continuation (through + * the aio_wake_function callback). + */ + BUG_ON(current->io_wait != NULL); + current->io_wait = &iocb->ki_wait; + ret = retry(iocb); + current->io_wait = NULL; + + if (-EIOCBRETRY != ret) { + if (-EIOCBQUEUED != ret) { + BUG_ON(!list_empty(&iocb->ki_wait.task_list)); + aio_complete(iocb, ret, 0); + /* must not access the iocb after this */ + } + } else { + /* + * Issue an additional retry to avoid waiting forever if + * no waits were queued (e.g. in case of a short read). + */ + if (list_empty(&iocb->ki_wait.task_list)) + kiocbSetKicked(iocb); + } +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); + } + } + 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. Expects to be called with ctx->ctx_lock held + */ +static int __aio_run_iocbs(struct kioctx *ctx) +{ + struct kiocb *iocb; + int count = 0; + LIST_HEAD(run_list); + + list_splice_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); + if (__aio_put_req(ctx, iocb)) /* drop extra ref */ + put_ioctx(ctx); + count++; + } + aio_run++; + 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_iocbs: + * Process all pending retries queued on the ioctx + * run list. + * Assumes it is operating within the aio issuer's mm + * context. + */ +static inline void aio_run_iocbs(struct kioctx *ctx) +{ + int requeue; + + spin_lock_irq(&ctx->ctx_lock); + + requeue = __aio_run_iocbs(ctx); + spin_unlock_irq(&ctx->ctx_lock); + if (requeue) + aio_queue_work(ctx); +} + +/* + * just like aio_run_iocbs, but keeps running them until + * the list stays empty + */ +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(void *data) +{ + struct kioctx *ctx = data; + mm_segment_t oldfs = get_fs(); + int requeue; + + set_fs(USER_DS); + use_mm(ctx->mm); + spin_lock_irq(&ctx->ctx_lock); + requeue =__aio_run_iocbs(ctx); + unuse_mm(ctx->mm); + spin_unlock_irq(&ctx->ctx_lock); + set_fs(oldfs); + /* + * we're in a worker thread already, don't use queue_delayed_work, + */ + if (requeue) + queue_work(aio_wq, &ctx->wq); +} + + +/* + * Called by kick_iocb to queue the kiocb for retry + * and if required activate the aio work queue to process + * it + */ +void queue_kicked_iocb(struct kiocb *iocb) +{ + struct kioctx *ctx = iocb->ki_ctx; + unsigned long flags; + int run = 0; + + WARN_ON((!list_empty(&iocb->ki_wait.task_list))); + + spin_lock_irqsave(&ctx->ctx_lock, flags); + run = __queue_kicked_iocb(iocb); + spin_unlock_irqrestore(&ctx->ctx_lock, flags); + if (run) { + aio_queue_work(ctx); + aio_wakeups++; + } +} + +/* + * kick_iocb: + * Called typically from a wait queue callback context + * (aio_wake_function) to trigger a retry of the iocb. + * The retry is usually executed by aio workqueue + * threads (See aio_kick_handler). + */ +void fastcall 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; + } + + iocb->ki_kicked++; + /* If its already kicked we shouldn't queue it again */ + if (!kiocbTryKick(iocb)) { + 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 fastcall 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. Note that this will not + * work if we allow sync kiocbs to be cancelled. in which + * case the usage count checks will have to move under ctx_lock + * for all cases. + */ + if (is_sync_kiocb(iocb)) { + int ret; + + iocb->ki_user_data = res; + if (iocb->ki_users == 1) { + iocb->ki_users = 0; + ret = 1; + } else { + spin_lock_irq(&ctx->ctx_lock); + iocb->ki_users--; + ret = (0 == iocb->ki_users); + spin_unlock_irq(&ctx->ctx_lock); + } + /* sync iocbs put the task here for us */ + wake_up_process(iocb->ki_obj.tsk); + return ret; + } + + 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], KM_IRQ1); + + tail = info->tail; + event = aio_ring_event(info, tail, KM_IRQ0); + tail = (tail + 1) % info->nr; + + 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, KM_IRQ0); + kunmap_atomic(ring, KM_IRQ1); + + pr_debug("added to ring %p at [%lu]\n", iocb, tail); + + pr_debug("%ld retries: %d of %d (kicked %ld, Q %ld run %ld wake %ld)\n", + iocb->ki_retried, + iocb->ki_nbytes - iocb->ki_left, iocb->ki_nbytes, + iocb->ki_kicked, iocb->ki_queued, aio_run, aio_wakeups); +put_rq: + /* everything turned out well, dispose of the aiocb. */ + ret = __aio_put_req(ctx, iocb); + + spin_unlock_irqrestore(&ctx->ctx_lock, flags); + + if (waitqueue_active(&ctx->wait)) + wake_up(&ctx->wait); + + if (ret) + put_ioctx(ctx); + + return ret; +} + +/* 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], KM_USER0); + 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, KM_USER1); + *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, KM_USER1); + } + spin_unlock(&info->ring_lock); + +out: + kunmap_atomic(ring, KM_USER0); + 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) +{ + init_timer(&to->timer); + to->timer.data = (unsigned long)to; + to->timer.function = timeout_func; + 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 event_loop = 0; /* testing only */ + 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; + ret = 0; + if (to.timed_out) /* Only check after read evt */ + break; + schedule(); + event_loop++; + 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: + pr_debug("event loop executed %d times\n", event_loop); + pr_debug("aio_run %ld\n", aio_run); + pr_debug("aio_wakeups %ld\n", aio_wakeups); + 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; + struct kioctx **tmp; + int was_dead; + + /* delete the entry from the list is someone else hasn't already */ + write_lock(&mm->ioctx_list_lock); + was_dead = ioctx->dead; + ioctx->dead = 1; + for (tmp = &mm->ioctx_list; *tmp && *tmp != ioctx; + tmp = &(*tmp)->next) + ; + if (*tmp) + *tmp = ioctx->next; + write_unlock(&mm->ioctx_list_lock); + + dprintk("aio_release(%p)\n", ioctx); + if (likely(!was_dead)) + put_ioctx(ioctx); /* twice for the list */ + + aio_cancel_all(ioctx); + wait_for_all_aios(ioctx); + put_ioctx(ioctx); /* once for the lookup */ +} + +/* 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. + */ +asmlinkage long sys_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 || (int)nr_events <= 0)) { + pr_debug("EINVAL: io_setup: ctx or nr_events > max\n"); + goto out; + } + + ioctx = ioctx_alloc(nr_events); + ret = PTR_ERR(ioctx); + if (!IS_ERR(ioctx)) { + ret = put_user(ioctx->user_id, ctxp); + if (!ret) + return 0; + + get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */ + io_destroy(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 -EFAULT if the context pointed to + * is invalid. + */ +asmlinkage long sys_io_destroy(aio_context_t ctx) +{ + struct kioctx *ioctx = lookup_ioctx(ctx); + if (likely(NULL != ioctx)) { + io_destroy(ioctx); + return 0; + } + pr_debug("EINVAL: io_destroy: invalid context id\n"); + return -EINVAL; +} + +/* + * Default retry method for aio_read (also used for first time submit) + * Responsible for updating iocb state as retries progress + */ +static ssize_t aio_pread(struct kiocb *iocb) +{ + struct file *file = iocb->ki_filp; + struct address_space *mapping = file->f_mapping; + struct inode *inode = mapping->host; + ssize_t ret = 0; + + ret = file->f_op->aio_read(iocb, iocb->ki_buf, + iocb->ki_left, iocb->ki_pos); + + /* + * Can't just depend on iocb->ki_left to determine + * whether we are done. This may have been a short read. + */ + if (ret > 0) { + iocb->ki_buf += ret; + iocb->ki_left -= ret; + /* + * For pipes and sockets we return once we have + * some data; for regular files we retry till we + * complete the entire read or find that we can't + * read any more data (e.g short reads). + */ + if (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode)) + ret = -EIOCBRETRY; + } + + /* 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; + + return ret; +} + +/* + * Default retry method for aio_write (also used for first time submit) + * Responsible for updating iocb state as retries progress + */ +static ssize_t aio_pwrite(struct kiocb *iocb) +{ + struct file *file = iocb->ki_filp; + ssize_t ret = 0; + + ret = file->f_op->aio_write(iocb, iocb->ki_buf, + iocb->ki_left, iocb->ki_pos); + + if (ret > 0) { + iocb->ki_buf += ret; + iocb->ki_left -= ret; + + ret = -EIOCBRETRY; + } + + /* 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; + + 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; +} + +/* + * aio_setup_iocb: + * Performs the initial checks and aio retry method + * setup for the kiocb at the time of io submission. + */ +ssize_t aio_setup_iocb(struct kiocb *kiocb) +{ + 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 = -EINVAL; + if (file->f_op->aio_read) + kiocb->ki_retry = aio_pread; + 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 = -EINVAL; + if (file->f_op->aio_write) + kiocb->ki_retry = aio_pwrite; + 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; +} + +/* + * aio_wake_function: + * wait queue callback function for aio notification, + * Simply triggers a retry of the operation via kick_iocb. + * + * This callback is specified in the wait queue entry in + * a kiocb (current->io_wait points to this wait queue + * entry when an aio operation executes; it is used + * instead of a synchronous wait when an i/o blocking + * condition is encountered during aio). + * + * Note: + * This routine is executed with the wait queue lock held. + * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests + * the ioctx lock inside the wait queue lock. This is safe + * because this callback isn't used for wait queues which + * are nested inside ioctx lock (i.e. ctx->wait) + */ +int aio_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key) +{ + struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait); + + list_del_init(&wait->task_list); + kick_iocb(iocb); + return 1; +} + +int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, + struct iocb *iocb) +{ + struct kiocb *req; + struct file *file; + ssize_t ret; + + /* enforce forwards compatibility on users */ + if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2 || + iocb->aio_reserved3)) { + 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); /* returns with 2 references to req */ + if (unlikely(!req)) { + fput(file); + return -EAGAIN; + } + + req->ki_filp = file; + iocb->aio_key = req->ki_key; + ret = put_user(iocb->aio_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; + init_waitqueue_func_entry(&req->ki_wait, aio_wake_function); + INIT_LIST_HEAD(&req->ki_wait.task_list); + req->ki_run_list.next = req->ki_run_list.prev = NULL; + req->ki_retry = NULL; + req->ki_retried = 0; + req->ki_kicked = 0; + req->ki_queued = 0; + aio_run = 0; + aio_wakeups = 0; + + ret = aio_setup_iocb(req); + + if (ret) + goto out_put_req; + + spin_lock_irq(&ctx->ctx_lock); + list_add_tail(&req->ki_run_list, &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; +} + +/* 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. + */ +asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr, + struct iocb __user * __user *iocbpp) +{ + struct kioctx *ctx; + long ret = 0; + int i; + + if (unlikely(nr < 0)) + return -EINVAL; + + 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; + } + + /* + * 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); + if (ret) + break; + } + + put_ioctx(ctx); + return i ? i : ret; +} + +/* lookup_kiocb + * Finds a given iocb for cancellation. + * MUST be called with ctx->ctx_lock held. + */ +struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, u32 key) +{ + struct list_head *pos; + /* 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. + */ +asmlinkage long sys_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 + printk(KERN_DEBUG "iocb has no cancel operation\n"); + + 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. May + * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range, + * if nr is out of range, if when is out of range. May fail with + * -EFAULT if any of the memory specified to is invalid. May return + * 0 or < min_nr if no events are available and the timeout specified + * by when has elapsed, where when == NULL specifies an infinite + * timeout. Note that the timeout pointed to by when is relative and + * will be updated if not NULL and the operation blocks. Will fail + * with -ENOSYS if not implemented. + */ +asmlinkage long sys_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 && nr >= 0)) + ret = read_events(ioctx, min_nr, nr, events, timeout); + put_ioctx(ioctx); + } + + return ret; +} + +__initcall(aio_setup); + +EXPORT_SYMBOL(aio_complete); +EXPORT_SYMBOL(aio_put_req); +EXPORT_SYMBOL(wait_on_sync_kiocb); |