From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D37ECC7618E for ; Mon, 24 Apr 2023 17:19:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6A2DE6B0075; Mon, 24 Apr 2023 13:19:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 652FA6B0078; Mon, 24 Apr 2023 13:19:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 51A7B6B007B; Mon, 24 Apr 2023 13:19:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 421036B0075 for ; Mon, 24 Apr 2023 13:19:14 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id E7BE940295 for ; Mon, 24 Apr 2023 17:19:13 +0000 (UTC) X-FDA: 80716945386.13.D170B30 Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) by imf24.hostedemail.com (Postfix) with ESMTP id 0788E180011 for ; Mon, 24 Apr 2023 17:19:10 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=gmail.com header.s=20221208 header.b=WUz8je7T; spf=pass (imf24.hostedemail.com: domain of fmdefrancesco@gmail.com designates 209.85.128.50 as permitted sender) smtp.mailfrom=fmdefrancesco@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1682356751; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=q5ffUKulywUVWsUyD54zTOn22OGaFxg4joquRNd4FgQ=; b=5oU5xbTbeXxJJbrSGD5auVWB0I5HvZjZH2kCkijkeulA0/03gK1sx2m1OgeN/Bku0LBE4A yZCR7NOGIgIUekK3nZLAsIisLP2xOMgtVPBIExuPHEpUYLPvhf4/htRKgiXHhuEsXPHyYc atY2Hl8SASEoBkDJ2SGS+X/DMeGT2Aw= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=gmail.com header.s=20221208 header.b=WUz8je7T; spf=pass (imf24.hostedemail.com: domain of fmdefrancesco@gmail.com designates 209.85.128.50 as permitted sender) smtp.mailfrom=fmdefrancesco@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1682356751; a=rsa-sha256; cv=none; b=7qXGskTX6nCJhLzvHOGcH10e4PJQv13721qupR/vgC6v4q/8xOVnoD5XZNaYkuXeHThYr3 7uhxfEJNqP5nDLToJxveuMCEeFxv0EGFsryEQovvYCHdAhpELfVZxlf5f+w7qSwLzOiqj0 pOGdjnKxrW586BF3L5mBZxpfLqmWyrM= Received: by mail-wm1-f50.google.com with SMTP id 5b1f17b1804b1-3f193ca059bso22638335e9.3 for ; Mon, 24 Apr 2023 10:19:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1682356749; x=1684948749; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=q5ffUKulywUVWsUyD54zTOn22OGaFxg4joquRNd4FgQ=; b=WUz8je7TAP9X0ZWTXN/DcIyVw3PSqQ6c+xZTy4D0RLal25VJ7IsPKmZdWbLw3jz7/K KVlkJcMB3+qjXl8qVGPpaChDawz7eLxlQnFKgYMc3g08s+N0nY4+q6TNXc2rli8wuJHf gcYnXs9U8/XouCegDQatfFV1D32O4Ui/ia3LrDFjUqR13p0pb0iEoTSkV9HrmAIC0DQo 1WEX2Vlu2Yho7dNkddLYnS4CcmcC/Ts+qaCzq0/pt00EcYBTQajLEBRbiURDAK9YXx90 439jUXDRabDTH9xDYyaHCEaAGhJJl2Fnclqag4G+/3vhHEyvO2IDXHin3qWrozA5ak49 nQ6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682356749; x=1684948749; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=q5ffUKulywUVWsUyD54zTOn22OGaFxg4joquRNd4FgQ=; b=QoFcKnfq4r8cy1FaRmOcqKPG52AZbDGYcCUzmCoo6iAB1CmGLKSnFmMbFy2YMSai0d Cq6NpQ/3mmUbG8yvdXJi1OeFP+KgZszXMs5amMO56MNuW/TgOqtM4Pn/iFdaSEqpo8O3 b0V0an5hrDAEbeFuPd95ij/T7TQG2/V+IClCcovWiOov/TRp5yaIbF3DgPoO7bxxMaVO STnFnV9l1Iqsz69Owxkzf8fkTs7vo+SEC/als4/tLjrdTXY/I8pkAECk6WUHCgU/Kj2v DUfgKLyoPdA8HFoudyRfTseMylWQnXRCacoOMaciOOELXvI9qHRDyiU5szZ6QiGjhinH 6SLQ== X-Gm-Message-State: AAQBX9db+rZ7hUMNGjri7ELgghKe9kUjPo1OFy1Al+nsITScI7/pkxfi tkInB11t4TLjCC6eT2c1cvDDetfE6cY= X-Google-Smtp-Source: AKy350Ywom400cz3IyOOqt4vzhP+ONiCCOrenGpF0cgItGHbLrhWmKEBovxp3ORq5wPXvjxIpaC9iw== X-Received: by 2002:a05:600c:22d4:b0:3f1:82c6:2d80 with SMTP id 20-20020a05600c22d400b003f182c62d80mr8679594wmg.5.1682356749143; Mon, 24 Apr 2023 10:19:09 -0700 (PDT) Received: from suse.localnet (host-79-36-111-57.retail.telecomitalia.it. [79.36.111.57]) by smtp.gmail.com with ESMTPSA id m18-20020a7bcb92000000b003f24f245f57sm3884154wmi.42.2023.04.24.10.19.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Apr 2023 10:19:08 -0700 (PDT) From: "Fabio M. De Francesco" To: David Howells Cc: Matthew Wilcox , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , David Howells , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Martin K. Petersen" , linux-scsi@vger.kernel.org, target-devel@vger.kernel.org Subject: Re: [PATCH v3 41/55] iscsi: Assume "sendpage" is okay in iscsi_tcp_segment_map() Date: Mon, 24 Apr 2023 19:19:04 +0200 Message-ID: <1957131.PYKUYFuaPT@suse> In-Reply-To: <20230331160914.1608208-42-dhowells@redhat.com> References: <20230331160914.1608208-1-dhowells@redhat.com> <20230331160914.1608208-42-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 0788E180011 X-Rspam-User: X-Stat-Signature: s9khtbcdxcqpi7eeyxcojcffynaa3ucm X-HE-Tag: 1682356750-357111 X-HE-Meta: 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 HMB8XUGw 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On venerd=EC 31 marzo 2023 18:09:00 CEST David Howells wrote: > As iscsi is now using sendmsg() with MSG_SPLICE_PAGES rather than sendpag= e, > assume that sendpage_ok() will return true in iscsi_tcp_segment_map() and > leave it to TCP to copy the data if not. >=20 > Signed-off-by: David Howells > cc: "Martin K. Petersen" > cc: "David S. Miller" > cc: Eric Dumazet > cc: Jakub Kicinski > cc: Paolo Abeni > cc: Jens Axboe > cc: Matthew Wilcox > cc: linux-scsi@vger.kernel.org > cc: target-devel@vger.kernel.org > cc: netdev@vger.kernel.org > --- > drivers/scsi/libiscsi_tcp.c | 13 +++---------- > 1 file changed, 3 insertions(+), 10 deletions(-) >=20 > diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c > index c182aa83f2c9..07ba0d864820 100644 > --- a/drivers/scsi/libiscsi_tcp.c > +++ b/drivers/scsi/libiscsi_tcp.c > @@ -128,18 +128,11 @@ static void iscsi_tcp_segment_map(struct iscsi_segm= ent > *segment, int recv) * coalescing neighboring slab objects into a single f= rag > which > * triggers one of hardened usercopy checks. > */ > - if (!recv && sendpage_ok(sg_page(sg))) > + if (!recv) > return; >=20 > - if (recv) { > - segment->atomic_mapped =3D true; > - segment->sg_mapped =3D kmap_atomic(sg_page(sg)); > - } else { > - segment->atomic_mapped =3D false; > - /* the xmit path can sleep with the page mapped so use=20 kmap */ > - segment->sg_mapped =3D kmap(sg_page(sg)); > - } > - > + segment->atomic_mapped =3D true; > + segment->sg_mapped =3D kmap_atomic(sg_page(sg)); As you probably know, kmap_atomic() is deprecated. I must admit that I'm not an expert of this code, however, it looks like th= e=20 mapping has no need to rely on the side effects of kmap_atomic() (i.e.,=20 pagefault_disable() and preempt_disable() - but I'm not entirely sure about= =20 the possibility that preemption should be explicitly disabled along with th= e=20 replacement with kmap_local_page()).=20 Last year I've been working on several conversions from kmap{,_atomic}() to= =20 kmap_local_page(), however I'm still not sure to understand what's happenin= g=20 here... Am I missing any important details? Can you please explain why we still nee= d=20 that kmap_atomic() instead of kmap_local_page()?=20 Thanks in advance, =46abio > segment->data =3D segment->sg_mapped + sg->offset + segment- >sg_offset; > }