eventpoll: clarify POLLFREE handshake comments

ep_remove_wait_queue() and the POLLFREE branch of ep_poll_callback()
are the two halves of a release/acquire handshake that lets a
subsystem (binder, signalfd, ...) tear down a wait-queue head from
under a registered epitem. The existing local comments documented the
race but did not name the protocol or refer readers from one side to
the other. After the previous commit added a "POLLFREE handshake"
section to the top-of-file banner, these sites can point at the
banner and at each other.

Rework the two comment blocks so that each side is labelled
"acquire side" or "release side", references the banner, and
explains its role in the protocol. On the release side fuse the two
former comments into one narrative: list_del_init() tolerates a
second delete from a racing ep_remove_wait_queue(), and the
smp_store_release() is what lets that racing remover discover the
teardown.

Comment-only; no functional change.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Link: https://patch.msgid.link/20260424-work-epoll-rework-v1-3-249ed00a20f3@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

0 files changed, 0 insertions, 0 deletions