From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 849931AD3EE; Tue, 18 Jun 2024 13:19:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718716780; cv=none; b=B+sywFCQeQ6EHAyKtEu3oDRshTndmtYvt3C9Y9joZGGE9EaQsYZw0qXRGl7qpuHUarALJQKA8Tifx7XSZ8pdfUvDmDEQwFaWyOCpWi+6FNesoPsi+p0JhN+6CCwsw5H9iajRu0wuNElcfcSeX547Gt+toOJvldt3GmfxrU2CuZ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718716780; c=relaxed/simple; bh=dPCLlqyWDebKbiKY13A+ywDSoOFBOmBvpvHmk8Jmaco=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EyfKEKteyuSgZyPNovAgVwnlA79KeejQ6Zdc7hF4fEZJMCcjLU+RDZK+2zg4GTuvc+ow2ZjLjBjLS4cYODkACz93oFC6FyuVOKblsh+naXeSSeg5d7hx4z5zifd6WE4Ni8jv+Rbj2XKwbizrzLlfL5Fheqil+McSTJh0gkLCd54= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=iYd7RBbj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="iYd7RBbj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3940C3277B; Tue, 18 Jun 2024 13:19:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718716780; bh=dPCLlqyWDebKbiKY13A+ywDSoOFBOmBvpvHmk8Jmaco=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iYd7RBbjK8Gr3VOPCdU15BFYyXzbcfIBd+TiOJXlVWNUyif/m8geS6Y84+bOZJtvu lSpEuAoh9EOJqK7K3FbpT+Vq9qdA1pwRRdNiYdKMvnm0JOmFU71WRQpkHY4cMG2zNf skjHqZZ+pRFLxtQAvJ/TokGC4I1N52QJXW5naO6E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, NeilBrown , Chuck Lever , Sasha Levin Subject: [PATCH 5.10 761/770] nfsd: Simplify code around svc_exit_thread() call in nfsd() Date: Tue, 18 Jun 2024 14:40:14 +0200 Message-ID: <20240618123436.646158137@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240618123407.280171066@linuxfoundation.org> References: <20240618123407.280171066@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown [ Upstream commit 18e4cf915543257eae2925671934937163f5639b ] Previously a thread could exit asynchronously (due to a signal) so some care was needed to hold nfsd_mutex over the last svc_put() call. Now a thread can only exit when svc_set_num_threads() is called, and this is always called under nfsd_mutex. So no care is needed. Not only is the mutex held when a thread exits now, but the svc refcount is elevated, so the svc_put() in svc_exit_thread() will never be a final put, so the mutex isn't even needed at this point in the code. Signed-off-by: NeilBrown Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfsd/nfssvc.c | 23 ----------------------- include/linux/sunrpc/svc.h | 13 ------------- 2 files changed, 36 deletions(-) diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index 8063fab2c0279..8907dba22c3f2 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -979,31 +979,8 @@ nfsd(void *vrqstp) atomic_dec(&nfsdstats.th_cnt); out: - /* Take an extra ref so that the svc_put in svc_exit_thread() - * doesn't call svc_destroy() - */ - svc_get(nn->nfsd_serv); - /* Release the thread */ svc_exit_thread(rqstp); - - /* We need to drop a ref, but may not drop the last reference - * without holding nfsd_mutex, and we cannot wait for nfsd_mutex as that - * could deadlock with nfsd_shutdown_threads() waiting for us. - * So three options are: - * - drop a non-final reference, - * - get the mutex without waiting - * - sleep briefly andd try the above again - */ - while (!svc_put_not_last(nn->nfsd_serv)) { - if (mutex_trylock(&nfsd_mutex)) { - nfsd_put(net); - mutex_unlock(&nfsd_mutex); - break; - } - msleep(20); - } - return 0; } diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index 5cf6543d3c8e5..1cf7a7799cc04 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -123,19 +123,6 @@ static inline void svc_put(struct svc_serv *serv) kref_put(&serv->sv_refcnt, svc_destroy); } -/** - * svc_put_not_last - decrement non-final reference count on SUNRPC serv - * @serv: the svc_serv to have count decremented - * - * Returns: %true is refcount was decremented. - * - * If the refcount is 1, it is not decremented and instead failure is reported. - */ -static inline bool svc_put_not_last(struct svc_serv *serv) -{ - return refcount_dec_not_one(&serv->sv_refcnt.refcount); -} - /* * Maximum payload size supported by a kernel RPC server. * This is use to determine the max number of pages nfsd is -- 2.43.0