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authorDavid Woodhouse <dwmw@amazon.co.uk>2020-10-27 16:55:21 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2020-11-15 17:49:10 +0300
commit28f1326710555bbe666f64452d08f2d7dd657cae (patch)
tree0500d5c7ff66eda5051b0221b04c73b28c8d8942 /include/linux/eventfd.h
parente8dbf19508a112d125190df77ee0464b7ba56192 (diff)
downloadlinux-28f1326710555bbe666f64452d08f2d7dd657cae.tar.xz
eventfd: Export eventfd_ctx_do_read()
Where events are consumed in the kernel, for example by KVM's irqfd_wakeup() and VFIO's virqfd_wakeup(), they currently lack a mechanism to drain the eventfd's counter. Since the wait queue is already locked while the wakeup functions are invoked, all they really need to do is call eventfd_ctx_do_read(). Add a check for the lock, and export it for them. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20201027135523.646811-2-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/linux/eventfd.h')
-rw-r--r--include/linux/eventfd.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
index dc4fd8a6644d..fa0a524baed0 100644
--- a/include/linux/eventfd.h
+++ b/include/linux/eventfd.h
@@ -41,6 +41,7 @@ struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
__u64 *cnt);
+void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
DECLARE_PER_CPU(int, eventfd_wake_count);
@@ -82,6 +83,11 @@ static inline bool eventfd_signal_count(void)
return false;
}
+static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
+{
+
+}
+
#endif
#endif /* _LINUX_EVENTFD_H */