From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 590CB50C2A3 for ; Fri, 4 Sep 2026 16:51:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788540663; cv=none; b=FuAvu+kPRTbWCTLhoDeK/XSDY4/LOE+mX5Cw/kPqDERKPhRfRuO0twilnBvZAti8wrKaQJpP6zMq/PxiirdfuoaYsv9ZcLmRJVWwv6ceX4ojCP4X1q1FgqVhLdZIib6cyhM1VunY2eTHIZHP1RdUL/qfFZufRgwTLUHCMoyqQ5U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788540663; c=relaxed/simple; bh=nVQPiYSA/W+nTWr/nB8jYaSHFmbuDH+e8Wms0APuJD0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Nu8FCCirHj9YP3/6avm4UAkApYhj54sdnVQU3KFjMqfLvDzWQ4WgqpJIKU+OU+B+OCMx6QFZR+uyAw8gVDc9csCD8EsKcEJcdhAqcGiSRbtZZrfavSjBWhkzIYMWpMoaxhX6PNxwsp9VB1723jRy6RH+cL1fxWD0ZhSgA8AloP0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RSwAz5Hu; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RSwAz5Hu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B32CC1F00AC4; Fri, 4 Sep 2026 16:51:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788540662; bh=BoWjZ4BTKVGrVlHDnmFYzvk0W4XPWydQSdDUz9D7kIA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RSwAz5Huj37BpBaR2XcnX9JbvFNXvPmKhr40qFa7LfNJcqd5d/cj347F+EztdHNcv 2FXOCK5igPxBZx2m/W3sIZ9+HeGi4AyWih/d4rm+zwOwER8r9iv3Uu22st79C8wUak L4hriBbxiH434dm4D0jayHCXa0OshYegjaNFQ8knqZHxkxJqsuYCZDtWPlPMWR6KHe 9YTFVezAEznY4GHtNfOGp/nVZ7VE/YClegnYnTtyHcjGJtS11/6PyigMmPmpXVEmR1 zsjPSDhO3xsaWZtbSG7lwlilSkHd+pc5EFh1uj2D20o9khnvMUfF3DFLEAXqfOG8UJ sYFevXugScHJg== From: Chuck Lever To: NeilBrown , Jeff Layton , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: Subject: [PATCH v2 10/10] xdrgen: Stream optional-data aggregate lists during encode Date: Fri, 4 Sep 2026 12:50:52 -0400 Message-ID: <20260904165052.153327-11-cel@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904165052.153327-1-cel@kernel.org> References: <20260904165052.153327-1-cel@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The optional-data aggregate encoder loops cursor.count times, so the begin hook must report the element count before the first element is written. A producer that reads its elements while the reply is encoded -- NFSv2 READDIR streaming directory entries straight into the send buffer -- does not know that count in advance, and would have to materialize the whole list just to satisfy the loop bound. An optional-data list carries no count on the wire, so nothing forces one on the encoder. Drive it from the item hook instead: a false return ends the list, and the framing writes the terminator. The counted-array form and its hook contract are unchanged. No in-tree spec marks an optional-data member yet, so no generated code changes here. Signed-off-by: Chuck Lever --- include/linux/sunrpc/xdrgen/_defs.h | 27 ++++++++++++------- tools/net/sunrpc/xdrgen/README | 11 ++++++-- .../C/struct/encoder/aggregate_optional.j2 | 6 ++--- 3 files changed, 29 insertions(+), 15 deletions(-) diff --git a/include/linux/sunrpc/xdrgen/_defs.h b/include/linux/sunrpc/xdrgen/_defs.h index f4375d73c5ca..d767206feea4 100644 --- a/include/linux/sunrpc/xdrgen/_defs.h +++ b/include/linux/sunrpc/xdrgen/_defs.h @@ -30,15 +30,24 @@ typedef struct { } opaque; /* - * Cursor a hook-driven aggregate codec hands to its application hooks, - * one element at a time, in place of a materialized C array. The - * generated framing owns it. @xdr is the RPC layer's stream; @ctx is - * that stream's xdrgen_ctx, the svc_rqst on the server. @index is - * the current element and @count the wire array length: a decoder - * fills @count from the wire before the begin hook runs, an - * encoder's begin hook sets it. @member_id selects among a type's - * marked members. The begin/item/end contract is under "Pragma - * aggregate" in tools/net/sunrpc/xdrgen/README. + * Cursor a hook-driven aggregate codec hands to its begin/item/end + * hooks, one element at a time, in place of a materialized C array. + * The generated framing owns it. @xdr is the RPC layer's stream and + * @ctx its xdrgen_ctx, the svc_rqst on the server. @index is the + * current element; @member_id selects among a type's marked members. + * For a counted array @count is the wire length: a decoder fills it + * before the begin hook runs, an encoder's begin hook sets it. The + * hook contract is under "Pragma aggregate" in + * tools/net/sunrpc/xdrgen/README. + * + * An optional-data list ("type *name") carries no count. Its encoder + * pulls elements until the item hook returns false. False ends the + * list rather than failing the encode: the framing writes the + * value-follows terminator, so a producer that stops early leaves a + * valid truncated list on the wire. A producer that stops for a + * mid-list error records it in the application state @ctx reaches, + * and either returns false from the end hook, which fails the + * encode, or reports it in the procedure status. */ struct xdrgen_aggregate_cursor { struct xdr_stream *xdr; diff --git a/tools/net/sunrpc/xdrgen/README b/tools/net/sunrpc/xdrgen/README index 15c6f6b0762a..0714808194ed 100644 --- a/tools/net/sunrpc/xdrgen/README +++ b/tools/net/sunrpc/xdrgen/README @@ -179,7 +179,14 @@ element is prefixed by a value-follows TRUE and the sequence is closed by a FALSE, which the framing writes after the last element. The element type must therefore be a pointer type, whose codec owns that framing; xdrgen rejects any other element type. -For the optional-data form xdrgen generates a working +That form has no count to loop on, so its encoder pulls +elements until the item hook returns false. False ends the list +rather than failing the encode: a producer stops when its source +is exhausted or when a reply budget fills. A producer that stops +for an error records it in its own state and either fails the +encode from the end hook or reports it in the procedure status. +For the optional-data +form xdrgen generates a working encoder only; the decoder it emits does not decode the list, so xdrgen also rejects the directive when the struct is reachable from an RPC argument. @@ -205,7 +212,7 @@ member: For a variable-length array, a decoder fills the cursor's count from the wire before calling the begin hook, and an encoder's begin hook sets that count for the framing to bound-check and emit. An -optional-data list's encoder begin hook sets the count as well; its +optional-data list's encoder does not read the count and its decoder never fills it. Once a begin hook has succeeded its end hook runs, so that it can release what begin took; the end hook receives the running success flag. diff --git a/tools/net/sunrpc/xdrgen/templates/C/struct/encoder/aggregate_optional.j2 b/tools/net/sunrpc/xdrgen/templates/C/struct/encoder/aggregate_optional.j2 index d45b823225f7..4f35b6976109 100644 --- a/tools/net/sunrpc/xdrgen/templates/C/struct/encoder/aggregate_optional.j2 +++ b/tools/net/sunrpc/xdrgen/templates/C/struct/encoder/aggregate_optional.j2 @@ -12,13 +12,11 @@ if (!{{ hook }}_encode_begin(&cursor)) return false; - for (cursor.index = 0; cursor.index < cursor.count; cursor.index++) { + for (cursor.index = 0; ; cursor.index++) { {{ classifier }}{{ c_type }} element = {}; - if (!{{ hook }}_encode(&cursor, &element)) { - ok = false; + if (!{{ hook }}_encode(&cursor, &element)) break; - } if (!xdrgen_encode_{{ type }}(xdr, &element)) { ok = false; break; -- 2.55.0