From mboxrd@z Thu Jan 1 00:00:00 1970 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 761E3301493 for ; Mon, 24 Nov 2025 12:43:47 +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=1763988229; cv=none; b=mneytEkFE2JRxXxyghZh9K65YXi7RO9JkPxl4uWx5Y/MZOGGamoKQCqDjdoSIJzDRDaZHNElMpFvD8bDo5Sz3VaVkdl8ZQR0DaEJQUeBccTBYLTx4h1xxPYmIomIgy539srfdmMH8V9Gn3rtmyZ54YGa5svIXDoBYCmjex3hxK0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763988229; c=relaxed/simple; bh=9azUYLxcrprXapB2AW29/5U1XZ7wheGbaYw8wddL248=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pxolZdAJApRLenqtk6alZ45ihD2ywXQKfzTzDyLNInIe1pvnkF2OAyQRpk9/b9XcKmXkKO2GJ21U97hI9lzPcM7G4UcLnkPOpFGgtmuT2FnpA8E1mLuSspM4QgvYkcAlq6mHfWht7AXorsTRKSnOW3umjP368NMajqfnA22Th2A= 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=bJuzlBKy; 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="bJuzlBKy" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1763988226; 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=bJuzlBKyKQkLcJLlkHa0g/HymU1gbLubZBOJUCJYqBHXHsx5oyDpEHwfwdoP1WaFWMuhR2 xi6mo7RIqJkhXpTLS6hk+SOodZVlGiJGANtIF98RothOJr83mEgM6xHKnjBbcU9m3mb1mX L6m9emKGsb6cdR9nJVHATXMFnN2K5cw= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-204-hn7XBzfvPq67pNfCEiOL2g-1; Mon, 24 Nov 2025 07:43:42 -0500 X-MC-Unique: hn7XBzfvPq67pNfCEiOL2g-1 X-Mimecast-MFC-AGG-ID: hn7XBzfvPq67pNfCEiOL2g_1763988220 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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8D448180057A; Mon, 24 Nov 2025 12:43:40 +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 3D1CE3003761; Mon, 24 Nov 2025 12:43:38 +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 v4 10/11] cifs: Don't need state locking in smb2_get_mid_entry() Date: Mon, 24 Nov 2025 12:42:49 +0000 Message-ID: <20251124124251.3565566-11-dhowells@redhat.com> In-Reply-To: <20251124124251.3565566-1-dhowells@redhat.com> References: <20251124124251.3565566-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 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 == CifsExiting) { - spin_unlock(&server->srv_lock); + switch (READ_ONCE(server->tcpStatus)) { + case CifsExiting: return -ENOENT; - } - - if (server->tcpStatus == 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 == CifsNeedNegotiate && - shdr->Command != SMB2_NEGOTIATE) { - spin_unlock(&server->srv_lock); - return -EAGAIN; - } - spin_unlock(&server->srv_lock); - - spin_lock(&ses->ses_lock); - if (ses->ses_status == SES_NEW) { - if ((shdr->Command != SMB2_SESSION_SETUP) && - (shdr->Command != SMB2_NEGOTIATE)) { - spin_unlock(&ses->ses_lock); + case CifsNeedNegotiate: + if (shdr->Command != SMB2_NEGOTIATE) return -EAGAIN; - } - /* else ok - we are setting up session */ + break; + default: + break; } - if (ses->ses_status == SES_EXITING) { - if (shdr->Command != SMB2_LOGOFF) { - spin_unlock(&ses->ses_lock); + switch (READ_ONCE(ses->ses_status)) { + case SES_NEW: + if (shdr->Command != SMB2_SESSION_SETUP && + shdr->Command != SMB2_NEGOTIATE) + return -EAGAIN; + /* else ok - we are setting up session */ + break; + case SES_EXITING: + if (shdr->Command != SMB2_LOGOFF) return -EAGAIN; - } /* else ok - we are shutting down the session */ + break; + default: + break; } - spin_unlock(&ses->ses_lock); *smb = smb2_mid_entry_alloc(shdr, server); if (*smb == NULL)