mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
synced 2025-10-31 03:13:59 +00:00
cb289d6244
KVM needs a wait to atomically remove themselves from the eventfd ->poll() wait queue head, in order to handle correctly their IRQfd deassign operation. This patch introduces such API, plus a way to read an eventfd from its context. Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Avi Kivity <avi@redhat.com>
84 lines
2.1 KiB
C
84 lines
2.1 KiB
C
/*
|
|
* include/linux/eventfd.h
|
|
*
|
|
* Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org>
|
|
*
|
|
*/
|
|
|
|
#ifndef _LINUX_EVENTFD_H
|
|
#define _LINUX_EVENTFD_H
|
|
|
|
#include <linux/fcntl.h>
|
|
#include <linux/file.h>
|
|
#include <linux/wait.h>
|
|
|
|
/*
|
|
* CAREFUL: Check include/asm-generic/fcntl.h when defining
|
|
* new flags, since they might collide with O_* ones. We want
|
|
* to re-use O_* flags that couldn't possibly have a meaning
|
|
* from eventfd, in order to leave a free define-space for
|
|
* shared O_* flags.
|
|
*/
|
|
#define EFD_SEMAPHORE (1 << 0)
|
|
#define EFD_CLOEXEC O_CLOEXEC
|
|
#define EFD_NONBLOCK O_NONBLOCK
|
|
|
|
#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
|
|
#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
|
|
|
|
#ifdef CONFIG_EVENTFD
|
|
|
|
struct file *eventfd_file_create(unsigned int count, int flags);
|
|
struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx);
|
|
void eventfd_ctx_put(struct eventfd_ctx *ctx);
|
|
struct file *eventfd_fget(int fd);
|
|
struct eventfd_ctx *eventfd_ctx_fdget(int fd);
|
|
struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
|
|
int eventfd_signal(struct eventfd_ctx *ctx, int n);
|
|
ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt);
|
|
int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_t *wait,
|
|
__u64 *cnt);
|
|
|
|
#else /* CONFIG_EVENTFD */
|
|
|
|
/*
|
|
* Ugly ugly ugly error layer to support modules that uses eventfd but
|
|
* pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
|
|
*/
|
|
static inline struct file *eventfd_file_create(unsigned int count, int flags)
|
|
{
|
|
return ERR_PTR(-ENOSYS);
|
|
}
|
|
|
|
static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
|
|
{
|
|
return ERR_PTR(-ENOSYS);
|
|
}
|
|
|
|
static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
|
|
static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
|
|
{
|
|
|
|
}
|
|
|
|
static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait,
|
|
__u64 *cnt)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
|
|
static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
|
|
wait_queue_t *wait, __u64 *cnt)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
|
|
#endif
|
|
|
|
#endif /* _LINUX_EVENTFD_H */
|
|
|