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 C4A5B38F62C; Sat, 28 Feb 2026 18:09:16 +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=1772302156; cv=none; b=ET3wKwqjDsoMTRJEzeQ3f5n5yNjsGsyRKAw/PVOIyAcnpjH1VyL6CgOKwN+vh1iiTj/zbF6scVKuhg4M/OU3eN53SfPcflL2KupCQCT8JZdRew0eqqT4ZPA41+sMT1ROmOlkPsFp7EGTJPPWLV4JKd1iT1Pbm5hpkLcjHtEs4rE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772302156; c=relaxed/simple; bh=nsgsaktJb3rTZJaRELnd3zg802ys78bGbm5rBVacZsE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dhE8EGYdqdlQJX/rRfyL9yI/IGbjMR4Xz79i7O3ZMQnjMECYTFoxH+PY/26+7slspjtbszR3v/dBOVJxkGJgKFTq5w6hdCXZtPaGGdN4b4U+sTXwGrH6IkvHgoBwBuVnjgJ9JODfKL09YZdCiv6N+ezETQVNa6Y+VVKuMdqQSNM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Mp+NDgjs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Mp+NDgjs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7DEEC116D0; Sat, 28 Feb 2026 18:09:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772302156; bh=nsgsaktJb3rTZJaRELnd3zg802ys78bGbm5rBVacZsE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Mp+NDgjs8WpRA67tgONp4O1cL9r658GqYK86qZaZoxgwoBOxNxh2/QmqlHQrv3QEQ A5Qfbhy5tgwYAxChSZScwGvoIdfine+7K+IkKz5w0r/AANXHeCkHC5B48UEBB56z4I 42ddgI3zWqaaPkxKhMlSmJBi6bd4w/R9lqrp/+f8u+74d4klVOO5r6RpRc66CPtMyT SuPxxMSaF/Vi1JHsNp2s87Um3BaYIFNxMOABXjKMrdeBb+5LMEO0Y6bFYBfTmATgtv uxkfl+9d7c/Pyp5iCMH36pYO+iahrJ4YyXPvhDNbQuxvh36gEt18MKCKh/6+/Q4k86 EsuNSRKtkRy4g== From: Sasha Levin To: patches@lists.linux.dev Cc: Stefan Metzmacher , Steve French , Tom Talpey , Long Li , Namjae Jeon , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, Steve French , Sasha Levin Subject: [PATCH 6.6 151/283] smb: client: correct value for smbd_max_fragmented_recv_size Date: Sat, 28 Feb 2026 13:04:53 -0500 Message-ID: <20260228180709.1583486-151-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228180709.1583486-1-sashal@kernel.org> References: <20260228180709.1583486-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit 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 be9be8f363319..359ab64e17d99 100644 --- a/fs/smb/client/smbdirect.c +++ b/fs/smb/client/smbdirect.c @@ -91,8 +91,23 @@ 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