From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f199.google.com (mail-pl1-f199.google.com [209.85.214.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84EF4231829 for ; Tue, 6 Oct 2026 23:32:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791329580; cv=none; b=N+wl5by5dc6tE4oCB1LOtnjuymdZ1xZ8DQqlK0LXfy9S/72btonid8gtNiYTwP1xJzMB2h4TBGrdLztOcAy5+g4eefnwmMkhT2KP67zJnxCZ7FnJVimF/cxwmW61+csIRpyVnDl8yNUgQZQEmGUFyeTDd3BZFbywsi9R5vU6zFI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791329580; c=relaxed/simple; bh=BLzJmYtg+5WKaReF54gIKTRlGEQtuRHyNEq1blvwsj0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=G5tnVknoKoDvs8ve9vLzVoy4yw85vkM5ouDJoyCNHzx23OcfFT73c5u4UyAnHpjwdOf6tjl4EZa9ljUXYRim315MJzLIh2BfCObm5AY6TqG0YjWE4cYV0yku4QWKL46N1AukgRNAagOXxf3eaD2FCc4e8JJ9aCujmlfnODlviS8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--praan.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Wn92HMDr; arc=none smtp.client-ip=209.85.214.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--praan.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Wn92HMDr" Received: by mail-pl1-f199.google.com with SMTP id d9443c01a7336-2e5d759038aso6880855ad.3 for ; Tue, 06 Oct 2026 16:32:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1791329579; x=1791934379; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=lFAbLk5EwoP2181kRqfEUrgA75aS3jBbGn0jFogrJ+w=; b=Wn92HMDrf/lc6gFler6FUTiKGNqTYSuR/Dhyl9Ape73N0AE5mKIfACjeM6vEZF/OPI yE4A4BLSFMSnwCDXghcy73pWGgbVBYLL71/JzhhEbwG1x4Zc10wKO3TOdCU5BcZRy5n+ gS4EJdlv4jsWfBEL2y+rVoCAfQgREnNLUlVgPhjer0myeIyQbIFQltwapZI4ssdXLFKf q+EmoQLFQiI+fhrw9m9VFbpLTj7GY+g73Ip44JhOCFKmXMR/vDLlffX2+zVNj+pFYM0+ jVI7RyWSfQKvUeZuB52bj8q7JNiNp8T1za75qcqb40wgJUl1peNZRSL/pIyYO4Sl/MmG 1PBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791329579; x=1791934379; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=lFAbLk5EwoP2181kRqfEUrgA75aS3jBbGn0jFogrJ+w=; b=zYeQxX1e/zAo+xz6zWURWKHQRv2Us2K/5P5UOaKkNxxOgNX28fCWvLl7f7vRuBW2rL 7SAwiMUKPoc5/Lr7e32ZoVsdd1uNy3nSeiBUZtystuTplyATDMam5uWowWPi4z0/JaLD SbSmg5HjRrAea4YV9m507Vrb2Q2C/yoSFJRCF/wTsFD4qGwGSsF5ufbp1U2eaXxI5/Kq L60q8mBygOa9PrpSdFK08m7ynysM35tkQgkBlrjtdb+Lw5MR84GXEmPJeiKBX8bg9vWL +sd6LNQxy82EiIaT+Yfp823DECxMG8tD9f1IHrTK8f/T+L0wcsU3UEZhRNrqrtNBWJk6 1pRw== X-Gm-Message-State: AFq9FYJDL0D5aWQIXBZrFfrE4ocm1yQ742lr9kiqOM2duhGV7noAX3Ii ljVT22jASDcJ8cpbD1q0KKr6xnKsk21BL1M/uxGMKRpJPqss3cdOgZPJx3J9ZS0+ZrE/ZOljkyS d/WQUJi+0Xqifhaqtvw3C/UQVQjjZpe1PYdK84xg4sfs9M1WjJ3Y2hQEqutOk78+sxx/kjChd/7 /YlhV6JBSV37kNtxIYEdTa/tD2f+FB4sma9AI= X-Received: from plbbh1.prod.google.com ([2002:a17:902:a981:b0:2e2:f305:e980]) (user=praan job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:e744:b0:2e4:c7ff:5309 with SMTP id d9443c01a7336-2e60057c74emr6840235ad.58.1791329577840; Tue, 06 Oct 2026 16:32:57 -0700 (PDT) Date: Tue, 6 Oct 2026 23:32:41 +0000 In-Reply-To: <20261006233248.705086-1-praan@google.com> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20261006233248.705086-1-praan@google.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog Message-ID: <20261006233248.705086-2-praan@google.com> Subject: [RFC PATCH v1 1/8] sunrpc: introduce XDRBUF_P2PDMA flag From: Pranjal Shrivastava To: linux-nfs@vger.kernel.org, Trond Myklebust , Anna Schumaker Cc: Chuck Lever , Jeff Layton , linux-kernel@vger.kernel.org, Christoph Hellwig , Logan Gunthorpe , Jason Gunthorpe , linux-pci@vger.kernel.org, linux-rdma@vger.kernel.org, Shivaji Kant , Tom Talpey , Leon Romanovsky , Unnati Sachan , Pranjal Shrivastava Content-Type: text/plain; charset="UTF-8" The NFS client will soon pass PCI peer-to-peer DMA (P2PDMA) pages to the transport as READ or WRITE payload. Only a transport that can DMA directly to and from that memory may move it. Introduce XDRBUF_P2PDMA and a helper, xprt_rqst_has_p2pdma(), to mark and detect requests whose pages are P2PDMA memory. The TCP (including TLS), UDP and AF_LOCAL transports return -EREMOTEIO for such a request before touching the socket. iov_iter_extract_pages() returns the same error today for P2PDMA pages the caller did not allow. Thus, users see no new error code. Signed-off-by: Pranjal Shrivastava --- include/linux/sunrpc/xdr.h | 1 + include/linux/sunrpc/xprt.h | 5 +++++ net/sunrpc/xprtsock.c | 12 ++++++++++++ 3 files changed, 18 insertions(+) diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index b102b4f21e6b..79526f47be2d 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -65,6 +65,7 @@ struct xdr_buf { #define XDRBUF_READ 0x01 /* target of file read */ #define XDRBUF_WRITE 0x02 /* source of file write */ #define XDRBUF_SPARSE_PAGES 0x04 /* Page array is sparse */ +#define XDRBUF_P2PDMA 0x08 /* Pages are P2PDMA memory */ unsigned int buflen, /* Total length of storage buffer */ len; /* Length of XDR encoded message */ diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index a82045804d34..08ab04fa4509 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -134,6 +134,11 @@ static inline int xprt_rqst_add_seqno(struct rpc_rqst *req, u32 seqno) return 0; } +static inline bool xprt_rqst_has_p2pdma(const struct rpc_rqst *req) +{ + return (req->rq_snd_buf.flags | req->rq_rcv_buf.flags) & XDRBUF_P2PDMA; +} + /* RPC transport layer security policies */ enum xprtsec_policies { RPC_XPRTSEC_NONE = 0, diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index f5a5136327ba..9fa6d7ec207e 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -962,6 +962,10 @@ static int xs_local_send_request(struct rpc_rqst *req) unsigned int sent; int status; + /* Sockets move data via CPU accesses, so refuse P2PDMA pages */ + if (xprt_rqst_has_p2pdma(req)) + return -EREMOTEIO; + /* Close the stream if the previous transmission was incomplete */ if (xs_send_request_was_aborted(transport, req)) { xprt_force_disconnect(xprt); @@ -1031,6 +1035,10 @@ static int xs_udp_send_request(struct rpc_rqst *req) unsigned int sent; int status; + /* Sockets move data via CPU accesses, so refuse P2PDMA pages */ + if (xprt_rqst_has_p2pdma(req)) + return -EREMOTEIO; + xs_pktdump("packet data:", req->rq_svec->iov_base, req->rq_svec->iov_len); @@ -1118,6 +1126,10 @@ static int xs_tcp_send_request(struct rpc_rqst *req) unsigned int sent; int status; + /* Sockets move data via CPU accesses, so refuse P2PDMA pages */ + if (xprt_rqst_has_p2pdma(req)) + return -EREMOTEIO; + /* Close the stream if the previous transmission was incomplete */ if (xs_send_request_was_aborted(transport, req)) { if (transport->sock != NULL) -- 2.56.0.rc1.315.gc6ed9934b7-goog