* Implements an efficient asynchronous io interface.
*
* Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
- * Copyright 2018 Christoph Hellwig.
*
* See ../COPYING for licensing terms.
*/
bool datasync;
};
-struct poll_iocb {
- struct file *file;
- __poll_t events;
- struct wait_queue_head *head;
-
- union {
- struct wait_queue_entry wait;
- struct work_struct work;
- };
-};
-
struct aio_kiocb {
union {
struct kiocb rw;
struct fsync_iocb fsync;
- struct poll_iocb poll;
};
struct kioctx *ki_ctx;
if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
iocb->aio_rw_flags))
return -EINVAL;
+
req->file = fget(iocb->aio_fildes);
if (unlikely(!req->file))
return -EBADF;
return 0;
}
-/* need to use list_del_init so we can check if item was present */
-static inline bool __aio_poll_remove(struct poll_iocb *req)
-{
- if (list_empty(&req->wait.entry))
- return false;
- list_del_init(&req->wait.entry);
- return true;
-}
-
-static inline void __aio_poll_complete(struct aio_kiocb *iocb, __poll_t mask)
-{
- fput(iocb->poll.file);
- aio_complete(iocb, mangle_poll(mask), 0);
-}
-
-static void aio_poll_work(struct work_struct *work)
-{
- struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, poll.work);
-
- if (!list_empty_careful(&iocb->ki_list))
- aio_remove_iocb(iocb);
- __aio_poll_complete(iocb, iocb->poll.events);
-}
-
-static int aio_poll_cancel(struct kiocb *iocb)
-{
- struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw);
- struct poll_iocb *req = &aiocb->poll;
- struct wait_queue_head *head = req->head;
- bool found = false;
-
- spin_lock(&head->lock);
- found = __aio_poll_remove(req);
- spin_unlock(&head->lock);
-
- if (found) {
- req->events = 0;
- INIT_WORK(&req->work, aio_poll_work);
- schedule_work(&req->work);
- }
- return 0;
-}
-
-static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
- void *key)
-{
- struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);
- struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
- struct file *file = req->file;
- __poll_t mask = key_to_poll(key);
-
- assert_spin_locked(&req->head->lock);
-
- /* for instances that support it check for an event match first: */
- if (mask && !(mask & req->events))
- return 0;
-
- mask = file->f_op->poll_mask(file, req->events) & req->events;
- if (!mask)
- return 0;
-
- __aio_poll_remove(req);
-
- /*
- * Try completing without a context switch if we can acquire ctx_lock
- * without spinning. Otherwise we need to defer to a workqueue to
- * avoid a deadlock due to the lock order.
- */
- if (spin_trylock(&iocb->ki_ctx->ctx_lock)) {
- list_del_init(&iocb->ki_list);
- spin_unlock(&iocb->ki_ctx->ctx_lock);
-
- __aio_poll_complete(iocb, mask);
- } else {
- req->events = mask;
- INIT_WORK(&req->work, aio_poll_work);
- schedule_work(&req->work);
- }
-
- return 1;
-}
-
-static ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb)
-{
- struct kioctx *ctx = aiocb->ki_ctx;
- struct poll_iocb *req = &aiocb->poll;
- __poll_t mask;
-
- /* reject any unknown events outside the normal event mask. */
- if ((u16)iocb->aio_buf != iocb->aio_buf)
- return -EINVAL;
- /* reject fields that are not defined for poll */
- if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
- return -EINVAL;
-
- req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
- req->file = fget(iocb->aio_fildes);
- if (unlikely(!req->file))
- return -EBADF;
- if (!file_has_poll_mask(req->file))
- goto out_fail;
-
- req->head = req->file->f_op->get_poll_head(req->file, req->events);
- if (!req->head)
- goto out_fail;
- if (IS_ERR(req->head)) {
- mask = EPOLLERR;
- goto done;
- }
-
- init_waitqueue_func_entry(&req->wait, aio_poll_wake);
- aiocb->ki_cancel = aio_poll_cancel;
-
- spin_lock_irq(&ctx->ctx_lock);
- spin_lock(&req->head->lock);
- mask = req->file->f_op->poll_mask(req->file, req->events) & req->events;
- if (!mask) {
- __add_wait_queue(req->head, &req->wait);
- list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
- }
- spin_unlock(&req->head->lock);
- spin_unlock_irq(&ctx->ctx_lock);
-done:
- if (mask)
- __aio_poll_complete(aiocb, mask);
- return 0;
-out_fail:
- fput(req->file);
- return -EINVAL; /* same as no support for IOCB_CMD_POLL */
-}
-
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
bool compat)
{
case IOCB_CMD_FDSYNC:
ret = aio_fsync(&req->fsync, &iocb, true);
break;
- case IOCB_CMD_POLL:
- ret = aio_poll(req, &iocb);
- break;
default:
pr_debug("invalid aio operation %d\n", iocb.aio_lio_opcode);
ret = -EINVAL;
projects / linux-2.6-microblaze.git / blobdiff