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From:   Gregory Erwin <gregerwin256@gmail.com>
Date:   Tue, 28 Jun 2022 20:41:44 -0700
Message-ID: <CAO+Okf56VAqKt5a6OoGUnMAoMsbQoBd7V_tcLf9yuqheWKH1SA@mail.gmail.com>
Subject: Re: [PATCH v7] ath9k: let sleep be interrupted when unregistering hwrng
To:     "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc:     Herbert Xu <herbert@gondor.apana.org.au>,
        linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
        =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= <toke@redhat.com>,
        Kalle Valo <kvalo@kernel.org>,
        Rui Salvaterra <rsalvaterra@gmail.com>, stable@vger.kernel.org
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Hmm, set_notify_signal() calls wake_up_state() in kernel/sched/core.c, which
is not currently exported. Only by including EXPORT_SYMBOL(wake_up_state) and
rebuilding vmlinux was I able to build rng-core.ko and load it successfully.

That said, this patch allows 'ip link set wlan0 down' to wake a blocked process
reading from /dev/hwrng, eliminating the delay as described. I'll give my
sign-off with the EXPORT_SYMBOL sorted out.