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 C4C712C21DF; Wed, 25 Feb 2026 06:56:27 +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=1772002587; cv=none; b=l/oR6JzO1ABLYcPKsQrz3Cd2nMJL4qqOiH6MBtdv+LorZMpmY4nCSXjswtY4htgXTqO9GHRI3pYAJoMh7k5Us6uJOwqAuu2+Ya+umQwF9AFXsco/VNgM0QVe+X1rJe5xioTLJ0JM4hGkl3hJ6UDo0D92f2S5MTUbS9wk4cLNk10= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772002587; c=relaxed/simple; bh=qno82xjE0r43n84cCm9gH5I548Dos3zTYYNX+9a9KIY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dFpmTgYN74e5jeMLM9S8CwbmSKYiXaWcl5AGfZ59ItL/shiSzdMlHnjde42FI60+MnvIizyfJuwGQXHpCMGvus57S1VCuaKh/1l6+GAnHWkiDTsOBJL4RTpCG4jprdqjmBn9EuqJ9wjzgpYDyK/UEAo1sXpXZNEXsJ9lcELE2eI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CKzZL4q4; 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="CKzZL4q4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9AF70C116D0; Wed, 25 Feb 2026 06:56:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1772002587; bh=qno82xjE0r43n84cCm9gH5I548Dos3zTYYNX+9a9KIY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CKzZL4q40CQhmupNEAXovA1Crdk9Q6iHP32LcuS0o5dspNScXndtg3c/zvY4G0+lh ZTJNWtYzwuQDVzW5uBbzUa3k8kWZYo0f06PmOI1fYDwY4rHyA6HFXE03yrAZz/N7lG uRzC28chQQCA3LSAh2yoxqov+01qqtQpWoTc0VZM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Steve French , Tom Talpey , Long Li , Namjae Jeon , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, Stefan Metzmacher , Steve French , Sasha Levin Subject: [PATCH 6.18 325/641] smb: client: correct value for smbd_max_fragmented_recv_size Date: Tue, 24 Feb 2026 17:20:51 -0800 Message-ID: <20260225012356.574749527@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260225012348.915798704@linuxfoundation.org> References: <20260225012348.915798704@linuxfoundation.org> User-Agent: quilt/0.69 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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefan Metzmacher [ Upstream commit 4a93d1ee2d0206970b6eb13fbffe07938cd95948 ] When we download a file without rdma offload or get a large directly enumeration from the server, the server might want to send up to smbd_max_fragmented_recv_size bytes, but if it is too large all our recv buffers might already be moved to the recv_io.reassembly.list and we're no longer able to grant recv credits. The maximum fragmented upper-layer payload receive size supported Assume max_payload_per_credit is smbd_max_receive_size - 24 = 1340 The maximum number would be smbd_receive_credit_max * max_payload_per_credit 1340 * 255 = 341700 (0x536C4) The minimum value from the spec is 131072 (0x20000) For now we use the logic we used in ksmbd before: (1364 * 255) / 2 = 173910 (0x2A756) Fixes: 03bee01d6215 ("CIFS: SMBD: Add SMB Direct protocol initial values and constants") Cc: Steve French Cc: Tom Talpey Cc: Long Li Cc: Namjae Jeon Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Signed-off-by: Stefan Metzmacher Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/smb/client/smbdirect.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/fs/smb/client/smbdirect.c b/fs/smb/client/smbdirect.c index 01d55bcc6d0f9..c8cef098d4806 100644 --- a/fs/smb/client/smbdirect.c +++ b/fs/smb/client/smbdirect.c @@ -101,8 +101,23 @@ int smbd_send_credit_target = 255; /* The maximum single message size can be sent to remote peer */ int smbd_max_send_size = 1364; -/* The maximum fragmented upper-layer payload receive size supported */ -int smbd_max_fragmented_recv_size = 1024 * 1024; +/* + * The maximum fragmented upper-layer payload receive size supported + * + * Assume max_payload_per_credit is + * smbd_max_receive_size - 24 = 1340 + * + * The maximum number would be + * smbd_receive_credit_max * max_payload_per_credit + * + * 1340 * 255 = 341700 (0x536C4) + * + * The minimum value from the spec is 131072 (0x20000) + * + * For now we use the logic we used in ksmbd before: + * (1364 * 255) / 2 = 173910 (0x2A756) + */ +int smbd_max_fragmented_recv_size = (1364 * 255) / 2; /* The maximum single-message size which can be received */ int smbd_max_receive_size = 1364; -- 2.51.0