From nobody Mon Dec 1 22:02:03 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 148D8304BDB for ; Mon, 1 Dec 2025 09:49:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764582601; cv=none; b=sG0byJIVqJTv3IHcEqmsDsGUViKEawoai8MyU3T+7zDeA27iw6qERlhgydNrmL3vlUc4SqJFO04ujfAmrF5cIVwCyr0JcmnwI8p1PztAH37KryB1TBjFWjhEEx2VSnUhC6gLEWcwkrGCG43isEN6lqIANd8KL1pYo0vmQThREwA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764582601; c=relaxed/simple; bh=9azUYLxcrprXapB2AW29/5U1XZ7wheGbaYw8wddL248=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UfRkzNPUZaFs5kTlJSLzwBglvUBEgNEAuDU+6uNkh61UlGOS20EUPEZjY/ssqYI0plsK2uSJgcXPYJcZe6TXNo4lkgCrtbMEK2PHUtrd6PwPtRhPcIkYcygGGTshnamE1hUfaGFQZRtS4WrSMpYNynlZiCkRE8iGyodJViL0Dfs= 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=bYtIZbWT; arc=none smtp.client-ip=170.10.133.124 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="bYtIZbWT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1764582598; 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=7FUmnWmOFPZ/yS6/aSdvHVfj2x2LVbiiAoaubXk9WOA=; b=bYtIZbWTh3FZsgSj43sl6D7qa/+3R2mzvKVLYR33xPVmd3QShuPGCjzKBx5g+yj+/sO9/J izPkLpuoCDsYGrHYLA5FTE1f0V7t6mr1c1VZoQP7XRFC9q4ZruF8tTGAWP/XpLXnYBXpof qJb2rdnG9yLIUFd/b9d7kSk/N3N18vw= 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-414-bDSs2Mu0PJO5yu94_NE8gQ-1; Mon, 01 Dec 2025 04:49:56 -0500 X-MC-Unique: bDSs2Mu0PJO5yu94_NE8gQ-1 X-Mimecast-MFC-AGG-ID: bDSs2Mu0PJO5yu94_NE8gQ_1764582594 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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 8F3FB19560A5; Mon, 1 Dec 2025 09:49:54 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.14]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C6B8730001A4; Mon, 1 Dec 2025 09:49:51 +0000 (UTC) From: David Howells To: Steve French Cc: David Howells , Paulo Alcantara , Shyam Prasad N , Stefan Metzmacher , linux-cifs@vger.kernel.org, netfs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Tom Talpey Subject: [PATCH v5 7/9] cifs: Don't need state locking in smb2_get_mid_entry() Date: Mon, 1 Dec 2025 09:49:11 +0000 Message-ID: <20251201094916.1418415-8-dhowells@redhat.com> In-Reply-To: <20251201094916.1418415-1-dhowells@redhat.com> References: <20251201094916.1418415-1-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 10.30.177.4 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 | 48 +++++++++++++++-------------------- 1 file changed, 20 insertions(+), 28 deletions(-) diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c index 6d76b0c6d73d..47eab3753c9e 100644 --- a/fs/smb/client/smb2transport.c +++ b/fs/smb/client/smb2transport.c @@ -684,43 +684,35 @@ static int smb2_get_mid_entry(struct cifs_ses *ses, struct TCP_Server_Info *server, struct smb2_hdr *shdr, 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; - } - - if (server->tcpStatus =3D=3D CifsNeedNegotiate && - shdr->Command !=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) { - if ((shdr->Command !=3D SMB2_SESSION_SETUP) && - (shdr->Command !=3D SMB2_NEGOTIATE)) { - spin_unlock(&ses->ses_lock); + case CifsNeedNegotiate: + if (shdr->Command !=3D SMB2_NEGOTIATE) return -EAGAIN; - } - /* else ok - we are setting up session */ + break; + default: + break; } =20 - if (ses->ses_status =3D=3D SES_EXITING) { - if (shdr->Command !=3D SMB2_LOGOFF) { - spin_unlock(&ses->ses_lock); + switch (READ_ONCE(ses->ses_status)) { + case SES_NEW: + if (shdr->Command !=3D SMB2_SESSION_SETUP && + shdr->Command !=3D SMB2_NEGOTIATE) + return -EAGAIN; + /* else ok - we are setting up session */ + break; + case SES_EXITING: + if (shdr->Command !=3D SMB2_LOGOFF) return -EAGAIN; - } /* else ok - we are shutting down the session */ + break; + default: + break; } - spin_unlock(&ses->ses_lock); =20 *smb =3D smb2_mid_entry_alloc(shdr, server); if (*smb =3D=3D NULL)