From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (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 E299E215055 for ; Wed, 1 Apr 2026 19:45:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775072713; cv=none; b=tTrSBsZd66j/BY7fO4gy/bYIvQS3gBJN+m5bFtw+5KZeL7tAZl9mhUv9wruF6rdsnpFXAruQv2H12l35zfUVabgYYf18OZrYbxHtBlksGWR5qxURVJgmYdk4dH1vDQeXX/T0S2jTtN3Xa6sv0ErDfVX8L9VtCthutxlo+z44KF0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775072713; c=relaxed/simple; bh=CdMDlHbKywlpFCBGl3OVn97IqE1emiTs97NUtj79NW4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=QwF0GL1+T5uE3c1hlbZS+MBVunrj4XiM8hEeC8UqN6KM4RyLHxXt0ayT6jW9Yk30RMHf9YhijxLQ1sNZYCWtw4LZNNp5j4ZoUAGXSxtytfUIxFCdAN4houL32N7vbNJLlbtonqpxnGwfuyY6y3H8oMXQaDHywkaP651RRCqS9oY= 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=hA1W8m8z; arc=none smtp.client-ip=209.85.216.74 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="hA1W8m8z" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-35da97f6a6dso63412a91.0 for ; Wed, 01 Apr 2026 12:45:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1775072711; x=1775677511; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=aZuzvlEZmJ6kG3JliNifQvylb1PwJkEr7RALOkoPIGk=; b=hA1W8m8zgARuk77AsW8or92x/33K/8LRlhGO2Qov8VBXJpR8pO/txk3b/C99NTZz61 mMSYiGAvwrXauP5RQkdoxFO6pXftp1ERcF4XQT/DLzrxk2jwwmMVBa1Ip+90Cf7OOg2e vwgG0lemNHUaFWWHRNqukxr+wwAIiCEYypUbU/zqi70nyntWheOWMI9dEivUyUkvgUZN maVJvxCeO8UZv+Gk5gb1yUgLyfPaGA6YlMIwz/DcYjRaTjg6JyNFB/fnVZgUty4+H3U/ lpav3gLad6XQsTfoXyEzk7162fj7y/QA0ebOVSeSMJVevFk+zWqXK6XyMUWnXi09GQGv GXFA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775072711; x=1775677511; h=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; bh=aZuzvlEZmJ6kG3JliNifQvylb1PwJkEr7RALOkoPIGk=; b=IDctxeyQqiD5pLBoqRnICMslCslfKWY7A0aWVwB0OlANW8Jjg3x7V1jk4cIluN/WQ2 bLaxeJRsIRhMwOPKyZiZBP8WeU3NpepqwFNxMXw5CY2bOkaat29S7YmvSiIpMk5Do5NQ 5fy3LUW/jmNFb8yIC/AAD8mF10hYdXl/k7tLeDawzbP8FKCtj+G9X7YQhwGJ8zK/mgnR M2OCJNihmP6JB2PfrKQR4/3faknAFWKu/5yYk0zW3umkYE0Ryg3/L5PtCqmGLn63fGP7 I6KKOT5ECANlm2ImxYIZIFiF4Qhsmss8oFirVmfiUn58ckYdaeMHUn3AUIa7gnqaBGIY tJvA== X-Forwarded-Encrypted: i=1; AJvYcCXCk828L8bmMBi6M5DIZbYDcnuVmbtLBP1skG1G01wI5giT56NkL4aGWh/KznCVspSStTaM+xA=@vger.kernel.org X-Gm-Message-State: AOJu0Yzs6KIH2R/oKVsO70Rqu71eZX4T5qH3uxTaWN30flXk3ZNn0wZj mQ3ehIfRVPm0Z91f7MxckwiezsrBEMTdLYJSrFJTEY07USwMhUipBiCV7DhKmvr6MIfLGvg7b9j rUw== X-Received: from pge24.prod.google.com ([2002:a05:6a02:2d18:b0:c76:a209:f392]) (user=praan job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:d491:b0:39b:f026:6f8e with SMTP id adf61e73a8af0-39ef7685e24mr4884632637.34.1775072711051; Wed, 01 Apr 2026 12:45:11 -0700 (PDT) Date: Wed, 1 Apr 2026 19:44:57 +0000 In-Reply-To: <20260401194501.2269200-1-praan@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260401194501.2269200-1-praan@google.com> X-Mailer: git-send-email 2.53.0.1185.g05d4b7b318-goog Message-ID: <20260401194501.2269200-2-praan@google.com> Subject: [RFC PATCH 1/4] sunrpc: add supports_p2pdma to rpc_xprt_ops From: Pranjal Shrivastava To: trond.myklebust@hammerspace.com, anna@kernel.org Cc: davem@davemloft.net, kuba@kernel.org, edumazet@google.com, pabeni@redhat.com, chuck.lever@oracle.com, jlayton@kernel.org, tom@talpey.com, okorniev@redhat.com, neil@brown.name, dai.ngo@oracle.com, linux-nfs@vger.kernel.org, netdev@vger.kernel.org, Pranjal Shrivastava Content-Type: text/plain; charset="UTF-8" Add a new transport op, supports_p2pdma, to allow upper layers (such as NFS) to query whether the underlying RPC transport supports PCI Peer-to-Peer DMA (P2PDMA). Since the capability is hardware-dependent. For the RDMA transport, implement this by querying the underlying InfiniBand device via ib_dma_pci_p2p_dma_supported() to ensures that P2PDMA is only attempted when both the transport and the HCA drivers support it. Signed-off-by: Pranjal Shrivastava --- include/linux/sunrpc/xprt.h | 1 + net/sunrpc/xprtrdma/transport.c | 9 +++++++++ 2 files changed, 10 insertions(+) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index f46d1fb8f71a..e451acd2e047 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -187,6 +187,7 @@ struct rpc_xprt_ops { void (*bc_free_rqst)(struct rpc_rqst *rqst); void (*bc_destroy)(struct rpc_xprt *xprt, unsigned int max_reqs); + bool (*supports_p2pdma)(struct rpc_xprt *xprt); }; /* diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index 9a8ce5df83ca..1c1714189a29 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -717,6 +717,14 @@ xprt_rdma_disable_swap(struct rpc_xprt *xprt) { } +static bool +xprt_rdma_supports_p2pdma(struct rpc_xprt *xprt) +{ + struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt); + + return ib_dma_pci_p2p_dma_supported(r_xprt->rx_ep->re_id->device); +} + /* * Plumbing for rpc transport switch and kernel module */ @@ -742,6 +750,7 @@ static const struct rpc_xprt_ops xprt_rdma_procs = { .enable_swap = xprt_rdma_enable_swap, .disable_swap = xprt_rdma_disable_swap, .inject_disconnect = xprt_rdma_inject_disconnect, + .supports_p2pdma = xprt_rdma_supports_p2pdma, #if defined(CONFIG_SUNRPC_BACKCHANNEL) .bc_setup = xprt_rdma_bc_setup, .bc_maxpayload = xprt_rdma_bc_maxpayload, -- 2.53.0.1185.g05d4b7b318-goog