| /* |
| * An async IO implementation for Linux |
| * Written by Benjamin LaHaise <bcrl@redhat.com> |
| * |
| * 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> |
| |
| //#define DEBUG 1 |
| |
| #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 <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 |
| |
| /*------ 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 spinlock_t fput_lock = SPIN_LOCK_UNLOCKED; |
| 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, NULL, NULL); |
| if (!kiocb_cachep) |
| panic("unable to create kiocb cache\n"); |
| |
| kioctx_cachep = kmem_cache_create("kioctx", sizeof(struct kioctx), |
| 0, SLAB_HWCACHE_ALIGN, NULL, NULL); |
| if (!kioctx_cachep) |
| panic("unable to create kioctx cache"); |
| |
| 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; |
| |
| info->nr_pages = nr_pages; |
| |
| 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; |
| 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); |
| |
| 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(); |
| |
| 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_user_obj = NULL; |
| |
| /* 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) |
| { |
| req->ki_ctx = NULL; |
| req->ki_filp = NULL; |
| req->ki_user_obj = 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; |
| } |
| |
| static void use_mm(struct mm_struct *mm) |
| { |
| struct mm_struct *active_mm = current->active_mm; |
| atomic_inc(&mm->mm_count); |
| current->mm = mm; |
| if (mm != active_mm) { |
| current->active_mm = mm; |
| activate_mm(active_mm, mm); |
| } |
| mmdrop(active_mm); |
| } |
| |
| static void unuse_mm(struct mm_struct *mm) |
| { |
| current->mm = NULL; |
| /* active_mm is still 'mm' */ |
| enter_lazy_tlb(mm, current); |
| } |
| |
| /* Run on kevent's context. FIXME: needs to be per-cpu and warn if an |
| * operation blocks. |
| */ |
| static void aio_kick_handler(void *data) |
| { |
| struct kioctx *ctx = data; |
| |
| use_mm(ctx->mm); |
| |
| spin_lock_irq(&ctx->ctx_lock); |
| while (!list_empty(&ctx->run_list)) { |
| struct kiocb *iocb; |
| long ret; |
| |
| iocb = list_entry(ctx->run_list.next, struct kiocb, |
| ki_run_list); |
| list_del(&iocb->ki_run_list); |
| iocb->ki_users ++; |
| spin_unlock_irq(&ctx->ctx_lock); |
| |
| kiocbClearKicked(iocb); |
| ret = iocb->ki_retry(iocb); |
| if (-EIOCBQUEUED != ret) { |
| aio_complete(iocb, ret, 0); |
| iocb = NULL; |
| } |
| |
| spin_lock_irq(&ctx->ctx_lock); |
| if (NULL != iocb) |
| __aio_put_req(ctx, iocb); |
| } |
| spin_unlock_irq(&ctx->ctx_lock); |
| |
| unuse_mm(ctx->mm); |
| } |
| |
| void fastcall kick_iocb(struct kiocb *iocb) |
| { |
| struct kioctx *ctx = iocb->ki_ctx; |
| |
| /* 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_user_obj); |
| return; |
| } |
| |
| if (!kiocbTryKick(iocb)) { |
| unsigned long flags; |
| spin_lock_irqsave(&ctx->ctx_lock, flags); |
| list_add_tail(&iocb->ki_run_list, &ctx->run_list); |
| spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
| schedule_work(&ctx->wq); |
| } |
| } |
| |
| /* 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_user_obj); |
| 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); |
| |
| 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_user_obj; |
| 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_user_obj, 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); |
| |
| /* 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 timeout { |
| struct timer_list timer; |
| int timed_out; |
| struct task_struct *p; |
| }; |
| |
| static void timeout_func(unsigned long data) |
| { |
| struct timeout *to = (struct timeout *)data; |
| |
| to->timed_out = 1; |
| wake_up_process(to->p); |
| } |
| |
| static inline void init_timeout(struct 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 timeout *to, |
| const struct timespec *ts) |
| { |
| unsigned long how_long; |
| |
| if (ts->tv_sec < 0 || (!ts->tv_sec && !ts->tv_nsec)) { |
| to->timed_out = 1; |
| return; |
| } |
| |
| how_long = ts->tv_sec * HZ; |
| #define HZ_NS (1000000000 / HZ) |
| how_long += (ts->tv_nsec + HZ_NS - 1) / HZ_NS; |
| |
| to->timer.expires = jiffies + how_long; |
| add_timer(&to->timer); |
| } |
| |
| static inline void clear_timeout(struct timeout *to) |
| { |
| del_timer_sync(&to->timer); |
| } |
| |
| static int read_events(struct kioctx *ctx, |
| long min_nr, long nr, |
| struct io_event *event, |
| struct timespec *timeout) |
| { |
| long start_jiffies = jiffies; |
| struct task_struct *tsk = current; |
| DECLARE_WAITQUEUE(wait, tsk); |
| int ret; |
| int i = 0; |
| struct io_event ent; |
| struct timeout to; |
| |
| /* needed to zero any padding within an entry (there shouldn't be |
| * any, but C is fun! |
| */ |
| memset(&ent, 0, sizeof(ent)); |
| 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 */ |
| |
| 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(); |
| 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: |
| 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 *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; |
| 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; |
| } |
| |
| 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; |
| char *buf; |
| |
| /* 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_user_obj = user_iocb; |
| req->ki_user_data = iocb->aio_data; |
| req->ki_pos = iocb->aio_offset; |
| |
| buf = (char *)(unsigned long)iocb->aio_buf; |
| |
| switch (iocb->aio_lio_opcode) { |
| case IOCB_CMD_PREAD: |
| ret = -EBADF; |
| if (unlikely(!(file->f_mode & FMODE_READ))) |
| goto out_put_req; |
| ret = -EFAULT; |
| if (unlikely(!access_ok(VERIFY_WRITE, buf, iocb->aio_nbytes))) |
| goto out_put_req; |
| ret = -EINVAL; |
| if (file->f_op->aio_read) |
| ret = file->f_op->aio_read(req, buf, |
| iocb->aio_nbytes, req->ki_pos); |
| break; |
| case IOCB_CMD_PWRITE: |
| ret = -EBADF; |
| if (unlikely(!(file->f_mode & FMODE_WRITE))) |
| goto out_put_req; |
| ret = -EFAULT; |
| if (unlikely(!access_ok(VERIFY_READ, buf, iocb->aio_nbytes))) |
| goto out_put_req; |
| ret = -EINVAL; |
| if (file->f_op->aio_write) |
| ret = file->f_op->aio_write(req, buf, |
| iocb->aio_nbytes, req->ki_pos); |
| break; |
| case IOCB_CMD_FDSYNC: |
| ret = -EINVAL; |
| if (file->f_op->aio_fsync) |
| ret = file->f_op->aio_fsync(req, 1); |
| break; |
| case IOCB_CMD_FSYNC: |
| ret = -EINVAL; |
| if (file->f_op->aio_fsync) |
| ret = file->f_op->aio_fsync(req, 0); |
| break; |
| default: |
| dprintk("EINVAL: io_submit: no operation provided\n"); |
| ret = -EINVAL; |
| } |
| |
| aio_put_req(req); /* drop extra ref to req */ |
| if (likely(-EIOCBQUEUED == ret)) |
| return 0; |
| aio_complete(req, ret, 0); /* will drop i/o 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 **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 *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_user_obj == 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 *iocb, |
| struct io_event *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 ++; |
| } 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_user_obj; |
| 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 *events, |
| struct timespec *timeout) |
| { |
| struct kioctx *ioctx = lookup_ioctx(ctx_id); |
| long ret = -EINVAL; |
| |
| if (unlikely(min_nr > nr || min_nr < 0 || nr < 0)) |
| return ret; |
| |
| if (likely(NULL != ioctx)) { |
| 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); |