From nobody Thu Dec 18 12:31:47 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 690882D130C for ; Wed, 6 Aug 2025 20:38:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754512741; cv=none; b=Qt9c/zp3uKCS3QGTjHMxN6P+BCKDrya5q0Z6dhPcYuSluaeYSkRIIroqUcNTSwh0kzVN4eiQ8Vt0AGjT4oixkNr5lxHZH1stRNRkbJyzCbEsdUen1Fc/7NgNnQbeELUVpKG50r/l9wR7bGGCfnQWlDkMdvGrLAgKjik2r7EMfGA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754512741; c=relaxed/simple; bh=sGkIqwI4kKVf31IFHCvik9vYPq7stY3n3/q2f/ete+w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kIJOZIzdyqrcZBwcYQH8644/sPDDwz/dqgTd/240zd5JJeJ8FYLtYmtJef9ujNYkeM7pn4dpfD/Z9Hsl6IsegdKbQpZLa4ofL6Og5IHxFMuTRJMDMVa+SVzoWf99/YYR22+SEDabPOTRrZ6qbs59MuRc1/CTeSE2MUpCLBxij/M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=N0WMvR/P; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="N0WMvR/P" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754512738; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fWFEygVcswswekGUvxP15RMRYsPo7UmyYBIY6DSNdhI=; b=N0WMvR/P4fZOLmBe/Ae2ROMzxejihQtZXBGDesy98QF2nyNECHg7vNuvVvIxJ7HvKH5qjR AGkHDzoohx9jhRrLgu6jPMhTkXkPlT1ayz009kg7Zbn7FVeiQY3upGtNCV6CZKjuhQKCF2 vOP2k4QefDLU5sfpBBnGtJXj1Kkv6zU= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-329-qk4wtJRiN2m4hgjIOSmZxw-1; Wed, 06 Aug 2025 16:38:54 -0400 X-MC-Unique: qk4wtJRiN2m4hgjIOSmZxw-1 X-Mimecast-MFC-AGG-ID: qk4wtJRiN2m4hgjIOSmZxw_1754512732 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 24DA2195608C; Wed, 6 Aug 2025 20:38:52 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.17]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 130C91800447; Wed, 6 Aug 2025 20:38:48 +0000 (UTC) From: David Howells To: Steve French Cc: David Howells , Paulo Alcantara , Shyam Prasad N , Tom Talpey , Wang Zhaolong , Stefan Metzmacher , Mina Almasry , linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org, netfs@lists.linux.dev, linux-fsdevel@vger.kernel.org Subject: [RFC PATCH 20/31] cifs: Don't need state locking in smb2_get_mid_entry() Date: Wed, 6 Aug 2025 21:36:41 +0100 Message-ID: <20250806203705.2560493-21-dhowells@redhat.com> In-Reply-To: <20250806203705.2560493-1-dhowells@redhat.com> References: <20250806203705.2560493-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" There's no need to get ->srv_lock or ->ses_lock in smb2_get_mid_entry() as all that happens of relevance (to the lock) inside the locked sections is the reading of one status value in each. Replace the locking with READ_ONCE() and use a switch instead of a chain of if-statements. Signed-off-by: David Howells cc: Steve French cc: Paulo Alcantara cc: Shyam Prasad N cc: Tom Talpey cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org --- fs/smb/client/smb2transport.c | 46 +++++++++++++++-------------------- 1 file changed, 19 insertions(+), 27 deletions(-) diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c index 7c60584a8544..7194082bb5ac 100644 --- a/fs/smb/client/smb2transport.c +++ b/fs/smb/client/smb2transport.c @@ -769,43 +769,35 @@ static int smb2_get_mid_entry(struct cifs_ses *ses, struct TCP_Server_Info *server, struct smb_message *smb) { - spin_lock(&server->srv_lock); - if (server->tcpStatus =3D=3D CifsExiting) { - spin_unlock(&server->srv_lock); + switch (READ_ONCE(server->tcpStatus)) { + case CifsExiting: return -ENOENT; - } - - if (server->tcpStatus =3D=3D CifsNeedReconnect) { - spin_unlock(&server->srv_lock); + case CifsNeedReconnect: cifs_dbg(FYI, "tcp session dead - return to caller to retry\n"); return -EAGAIN; + case CifsNeedNegotiate: + if (smb->command_id !=3D SMB2_NEGOTIATE) + return -EAGAIN; + break; + default: + break; } =20 - if (server->tcpStatus =3D=3D CifsNeedNegotiate && - smb->command_id !=3D SMB2_NEGOTIATE) { - spin_unlock(&server->srv_lock); - return -EAGAIN; - } - spin_unlock(&server->srv_lock); - - spin_lock(&ses->ses_lock); - if (ses->ses_status =3D=3D SES_NEW) { + switch (READ_ONCE(ses->ses_status)) { + case SES_NEW: if (smb->command_id !=3D SMB2_SESSION_SETUP && - smb->command_id !=3D SMB2_NEGOTIATE) { - spin_unlock(&ses->ses_lock); + smb->command_id !=3D SMB2_NEGOTIATE) return -EAGAIN; - } - /* else ok - we are setting up session */ - } - - if (ses->ses_status =3D=3D SES_EXITING) { - if (smb->command_id !=3D SMB2_LOGOFF) { - spin_unlock(&ses->ses_lock); + /* else ok - we are setting up session */ + break; + case SES_EXITING: + if (smb->command_id !=3D SMB2_LOGOFF) return -EAGAIN; - } /* else ok - we are shutting down the session */ + break; + default: + break; } - spin_unlock(&ses->ses_lock); =20 smb2_init_mid(smb, server);