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Sat, 25 Oct 2025 16:37:49 -0700 (PDT) Message-ID: <0a9d9e34-a351-4168-bbdc-3ca3b6c3e17b@kernel.dk> Date: Sat, 25 Oct 2025 17:37:48 -0600 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/5] io_uring/zcrx: add refcount to struct io_zcrx_ifq To: David Wei , io-uring@vger.kernel.org, netdev@vger.kernel.org Cc: Pavel Begunkov References: <20251025191504.3024224-1-dw@davidwei.uk> <20251025191504.3024224-3-dw@davidwei.uk> Content-Language: en-US From: Jens Axboe In-Reply-To: <20251025191504.3024224-3-dw@davidwei.uk> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/25/25 1:15 PM, David Wei wrote: > diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c > index a816f5902091..22d759307c16 100644 > --- a/io_uring/zcrx.c > +++ b/io_uring/zcrx.c > @@ -730,6 +731,8 @@ void io_shutdown_zcrx_ifqs(struct io_ring_ctx *ctx) > lockdep_assert_held(&ctx->uring_lock); > > xa_for_each(&ctx->zcrx_ctxs, index, ifq) { > + if (refcount_read(&ifq->refs) > 1) > + continue; This is a bit odd, it's not an idiomatic way to use reference counts. Why isn't this a refcount_dec_and_test()? Given that both the later grab when sharing is enabled and the shutdown here are under the ->uring_lock this may not matter, but it'd be a lot more obviously correct if it looked ala: if (refcount_dec_and_test(&ifq->refs)) { io_zcrx_scrub(ifq); io_close_queue(ifq); } instead? -- Jens Axboe