eventfd: Add eventfd_signal()
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Authored by dumbbell on Jun 14 2025, 5:23 PM.

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Reviewers

markj

Group Reviewers

linuxkpi

Summary

The eventfd_signal() function is the equivalent to a write to an eventfd file descriptor: it bumps the internal counter and wakes up processes waiting for it.

eventfd_signal() is meant to be used by kernel drivers. DRM drivers will call it through linuxkpi.

This is a requirement to the following patch to drm-kmod:
https://github.com/freebsd/drm-kmod/pull/358

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Event Timeline

dumbbell created this revision.Jun 14 2025, 5:23 PM

Herald added subscribers: olce, imp. · View Herald TranscriptJun 14 2025, 5:23 PM

dumbbell requested review of this revision.Jun 14 2025, 5:23 PM

dumbbell edited the summary of this revision. (Show Details)Jun 14 2025, 5:50 PM

emaste added a parent revision: D50848: eventfd: Rename `struct eventfd` to `struct eventfd_ctx`.Jun 24 2025, 1:33 PM

emaste added a child revision: D50853: linuxkpi: Add eventfd_*().

markj accepted this revision.Sun, Nov 30, 4:42 PM

markj added a subscriber: markj.

markj added inline comments.

sys/kern/sys_eventfd.c
158	What's the purpose of having the `mask` parameter? Do you plan to extend this in the future?
167	It would be better to share this code with eventfd_write(), but it is not critical.