From nobody Tue Dec 2 01:03:33 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 CBF602D321B for ; Mon, 1 Dec 2025 22:58:14 +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=1764629896; cv=none; b=iKzvtbsyMy7hGWgKiukumJAlR0vlUTK6jX6RjpUHClZFlhdiOTHJoTk0xwEi6EdXV0CTEFXfL9wvZjOjLY0UVHhubtpsHqPyW6kbIqKltnIOh2//86lXqZ5JZeDiezKOX+rZ0++eBDfJPKCNBDMIpRweDKEUtflKlL40pWiW3u0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764629896; c=relaxed/simple; bh=kVAzsdYACNxCMIlrstbDN4TiRE8cu9bDDpWkvccgviQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CTlZG7RbkDlGzX6B53omhyj4KhCLE/e9D/K0MtdrDcGLBXYoJ5s5NV2ptsM2xfHC8AGenWmNnMsBJ3a+361zYm9x9SxJ/UINsZcOrxNoyUxcpCMNelcf58r2DoONaOZPizbIdmINzkI1sGtb3WVkY8cCtmr02rDr5056FhHcI5M= 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=Pe7iCBHu; 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="Pe7iCBHu" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1764629893; 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=nkk/qeDFISFqpoIzreaKbH6PF7a/zBmUeahYIhhBiU0=; b=Pe7iCBHugHYUIy9Ei8puw4UF5smgSVOcjbKkXhqQ6tyhRkFOReYRIbv77FU+fD+xlbwNqA NmhpHe61NcnG1scca1kMbizMMi2MCn+kUzWpPVPXRGXpBsTYV2ZQmtHl9owG0tT49lbVYO 5gUlBj2qjBLDpTbhwLlMnGV+7tI+hmc= Received: from mx-prod-mc-05.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-468-wXejG35tPvKSbc0osxpLlw-1; Mon, 01 Dec 2025 17:58:10 -0500 X-MC-Unique: wXejG35tPvKSbc0osxpLlw-1 X-Mimecast-MFC-AGG-ID: wXejG35tPvKSbc0osxpLlw_1764629888 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B75F1195609D; Mon, 1 Dec 2025 22:58:08 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.14]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 23C0219560B2; Mon, 1 Dec 2025 22:58:05 +0000 (UTC) From: David Howells To: Steve French Cc: David Howells , Paulo Alcantara , Shyam Prasad N , Stefan Metzmacher , Tom Talpey , linux-cifs@vger.kernel.org, netfs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 7/9] cifs: Don't need state locking in smb2_get_mid_entry() Date: Mon, 1 Dec 2025 22:57:28 +0000 Message-ID: <20251201225732.1520128-8-dhowells@redhat.com> In-Reply-To: <20251201225732.1520128-1-dhowells@redhat.com> References: <20251201225732.1520128-1-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 3.0 on 10.30.177.12 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 d06f872c9ab2..99fa48bcd459 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 mid_q_entry **mid) { - 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 *mid =3D smb2_mid_entry_alloc(shdr, server); if (*mid =3D=3D NULL)