From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) (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 21AB73BBFC5 for ; Tue, 6 Oct 2026 23:33:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791329592; cv=none; b=GnaHmsMYsdvyfkaEqsX7d4rypbTdtZec8zVT0R6dgvlIvu1/j5YbXRDwYMue/ZRsniJDmbWtBL64sHSCvbgbcvAR68yN61CcZ5bBzwYkEEoIWE9/0j9RpGoJWklTrAXHdZG8W/9mi4QcSl0KUBMdzsI1NhX/CvZvArZGZBu0AlE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791329592; c=relaxed/simple; bh=6do5GILneM2SelSiDGSkhgGo9BTvgOAIY7d7Bg1SjQ8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=HLFxp5jt1o6Fj9cjLbh+aK0ENN1PyK6g6Rw9qAJ7byGJvHMA9+ClPifzmYGTKXKXyy8rAELTTQrdgRZolpW4POk8Vk59m8GOoaMNFxLDg4Jj5bolvZTqDDZSgp0++AMLWj8tNU8ERqHwfQULJ7rb8R5lxOJf3hhKpYSWQx3DdTg= 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=MnEnWh2f; arc=none smtp.client-ip=209.85.215.197 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="MnEnWh2f" Received: by mail-pg1-f197.google.com with SMTP id 41be03b00d2f7-cb11535e6a1so1735336a12.0 for ; Tue, 06 Oct 2026 16:33:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1791329588; x=1791934388; 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=Uzjnm4DC8/yngbTXbJn1X0a1+gZkIVZaTLffWNrxWJE=; b=MnEnWh2fR6g1/Zzg1XlOWgScAw+AQt1DDv2dqPeh/wfRdCXRJ4kPh3e2uOOe1gVAc6 uSRyBWI2PLCHM3h7GjbPRSAg/QCv2P1Ly34zAkdXv85tyZSuY881wgoeU9FxTVRLu3qo yfVgXbpIbOY5gdxNLIwsGKen3+CKHErb2JfKlFF+AEx9fHcOt2Vbz8eLV9gQ6duWctaW ujoR4ERDLpk8dZIu+CP1LYUt0lNoI3dG2kj3JBcjvdfejJ5an520et1SL1kTqQkyT4Ue Hkc1H/WySsePnInMCowfSCQWij7R4pcg/Aq8yv7WZaFKqsZ0tDSk/b4QMXjCjGBQvKFq ajzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791329588; x=1791934388; 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=Uzjnm4DC8/yngbTXbJn1X0a1+gZkIVZaTLffWNrxWJE=; b=yBUn2SRAo48O9S98s2wJxfSCHix+6/2qvARXE30wELVVT8cYd+fLHXdJOYh0Fttb1t KCtA3nfmgDpN6wKWVNr2BT+M+XK2M7TnUN8g8YzyE9ssIAfsgHGuLPC8F8nvLzW9HkYD XU1218Dwa9PSehKc4oRSHw5DNBLdij+1zEr2hnpJDMBoFmAgG/puwBsRFgHr7NPzNcsJ rbuIorJGQwH793JW/Cf+QKBcwKY/uPSQcY8Gxn+BEPdaIYnDfhN+ILaaJKbciOyABbF4 zVOUchgHnDcleo+W12ZCWIocQD0JA6IdQvH6E2s6k71p0t0kq8m8C3ULLRu11+BbVNMU BByQ== X-Forwarded-Encrypted: i=1; AKwUvByOCRuafxHA45N5Ia7zmPXZsVjXIwpXgJPXmAuyjmMKTL4YV131oSXNgInEG639Uk1QQDAN+T0YONw=@vger.kernel.org X-Gm-Message-State: AFuF++nZHJFVdibU3zrQ6b5FLjnGA+19jcb3ICuKAPmANZn38PmGYpH7 vNl6mqgaIuWNSbys7OYA2r+x0uh1+oUaC9MisCi64dX8TSNSZwjRrghuJIfINTNN3PM+M3MWQrI bXg== X-Received: from pgbd18-n1.prod.google.com ([2002:a05:6a02:64d2:10b0:cc7:b263:342e]) (user=praan job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:484:b0:3de:247d:73de with SMTP id adf61e73a8af0-3e133fffe0bmr404483637.19.1791329588288; Tue, 06 Oct 2026 16:33:08 -0700 (PDT) Date: Tue, 6 Oct 2026 23:32:45 +0000 In-Reply-To: <20261006233248.705086-1-praan@google.com> Precedence: bulk X-Mailing-List: linux-pci@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: <20261006233248.705086-6-praan@google.com> Subject: [RFC PATCH v1 5/8] nfs: tag READ/WRITE RPCs carrying P2PDMA pages 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" A transport must know when an RPC's payload pages are P2PDMA memory, so it can move them by DMA or refuse the RPC. Check each page as nfs_generic_pgio() builds the page array, and record the result in nfs_pgio_args. The READ and WRITE encoders of every NFS version then set XDRBUF_P2PDMA on the buffer holding the payload. Additionally, avoid using READ_PLUS when the pages are P2PDMA memory. Signed-off-by: Pranjal Shrivastava --- fs/nfs/nfs2xdr.c | 4 ++++ fs/nfs/nfs3xdr.c | 4 ++++ fs/nfs/nfs4proc.c | 3 +++ fs/nfs/nfs4xdr.c | 4 ++++ fs/nfs/pagelist.c | 2 ++ include/linux/nfs_xdr.h | 1 + 6 files changed, 18 insertions(+) diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c index 9eff09158518..5a8f2eccd068 100644 --- a/fs/nfs/nfs2xdr.c +++ b/fs/nfs/nfs2xdr.c @@ -628,6 +628,8 @@ static void nfs2_xdr_enc_readargs(struct rpc_rqst *req, rpc_prepare_reply_pages(req, args->pages, args->pgbase, args->count, NFS_readres_sz - NFS_pagepad_sz); req->rq_rcv_buf.flags |= XDRBUF_READ; + if (args->p2pdma) + req->rq_rcv_buf.flags |= XDRBUF_P2PDMA; } /* @@ -668,6 +670,8 @@ static void nfs2_xdr_enc_writeargs(struct rpc_rqst *req, encode_writeargs(xdr, args); xdr->buf->flags |= XDRBUF_WRITE; + if (args->p2pdma) + xdr->buf->flags |= XDRBUF_P2PDMA; } /* diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c index e745e78faab0..e39c58883a2a 100644 --- a/fs/nfs/nfs3xdr.c +++ b/fs/nfs/nfs3xdr.c @@ -946,6 +946,8 @@ static void nfs3_xdr_enc_read3args(struct rpc_rqst *req, rpc_prepare_reply_pages(req, args->pages, args->pgbase, args->count, replen); req->rq_rcv_buf.flags |= XDRBUF_READ; + if (args->p2pdma) + req->rq_rcv_buf.flags |= XDRBUF_P2PDMA; } /* @@ -988,6 +990,8 @@ static void nfs3_xdr_enc_write3args(struct rpc_rqst *req, encode_write3args(xdr, args); xdr->buf->flags |= XDRBUF_WRITE; + if (args->p2pdma) + xdr->buf->flags |= XDRBUF_P2PDMA; } /* diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index beb659744760..443079f5adc9 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -5721,6 +5721,9 @@ static int nfs4_read_done(struct rpc_task *task, struct nfs_pgio_header *hdr) static bool nfs42_read_plus_support(struct nfs_pgio_header *hdr, struct rpc_message *msg) { + /* P2PDMA payloads move only by DMA */ + if (hdr->args.p2pdma) + return false; /* Note: We don't use READ_PLUS with pNFS yet */ if (nfs_server_capable(hdr->inode, NFS_CAP_READ_PLUS) && !hdr->ds_clp) { msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ_PLUS]; diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c index 8b3d96b4a0f0..04765b56de28 100644 --- a/fs/nfs/nfs4xdr.c +++ b/fs/nfs/nfs4xdr.c @@ -2621,6 +2621,8 @@ static void nfs4_xdr_enc_read(struct rpc_rqst *req, struct xdr_stream *xdr, rpc_prepare_reply_pages(req, args->pages, args->pgbase, args->count, hdr.replen - pagepad_maxsz); req->rq_rcv_buf.flags |= XDRBUF_READ; + if (args->p2pdma) + req->rq_rcv_buf.flags |= XDRBUF_P2PDMA; encode_nops(&hdr); } @@ -2686,6 +2688,8 @@ static void nfs4_xdr_enc_write(struct rpc_rqst *req, struct xdr_stream *xdr, encode_putfh(xdr, args->fh, &hdr); encode_write(xdr, args, &hdr); req->rq_snd_buf.flags |= XDRBUF_WRITE; + if (args->p2pdma) + req->rq_snd_buf.flags |= XDRBUF_P2PDMA; if (args->bitmask) encode_getfattr(xdr, args->bitmask, &hdr); encode_nops(&hdr); diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 71f0ce2bc4ea..3ec4e1e5fe1f 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -970,6 +970,8 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc, if (pageused > pagecount) goto full; *pages++ = last_page = page; + if (is_pci_p2pdma_page(page)) + hdr->args.p2pdma = true; } } } diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h index c0e29b4dfa62..85cdee107559 100644 --- a/include/linux/nfs_xdr.h +++ b/include/linux/nfs_xdr.h @@ -685,6 +685,7 @@ struct nfs_pgio_args { __u32 count; unsigned int pgbase; struct page ** pages; + bool p2pdma; /* pages include P2PDMA memory */ union { unsigned int replen; /* used by read */ struct { -- 2.56.0.rc1.315.gc6ed9934b7-goog