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Donenfeld via Linux-f2fs-devel" Reply-To: "Jason A. Donenfeld" Cc: Andrew Lunn , "Darrick J . Wong" , Ulf Hansson , dri-devel@lists.freedesktop.org, Andrii Nakryiko , Hans Verkuil , linux-sctp@vger.kernel.org, "Md . Haris Iqbal" , Miquel Raynal , Christoph Hellwig , Andy Gospodarek , Sergey Matyukevich , Rohit Maheshwari , Michael Ellerman , ceph-devel@vger.kernel.org, Christophe Leroy , Jozsef Kadlecsik , Nilesh Javali , Jean-Paul Roubelat , Dick Kennedy , Jay Vosburgh , Potnuri Bharat Teja , Vinay Kumar Yadav , linux-nfs@vger.kernel.org, Nicholas Piggin , Igor Mitsyanko , Andy Lutomirski , linux-hams@vger.kernel.org, Thomas Gleixner , Trond Myklebust , linux-raid@vger.kernel.org, Neil Horman , Hante Meuleman , Greg Kroah-Hartman , linux-usb@vger.kernel.org, Michael Chan , linux-kernel@vger.kernel.org, Varun Prakash , Chuck Lever , netfilter-devel@vger.kernel.org, Masami Hiramatsu , Jiri Olsa , Jan Kara , linux-fsdevel@vger.kernel.org, Lars Ellenberg , linux-media@vger.kernel.org, Claudiu Beznea , Sharvari Harisangam , linux-fbdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-mmc@vger.kernel.org, Dave Hansen , Song Liu , Eric Dumazet , target-devel@vger.kernel.org, John Stultz , Stanislav Fomichev , Gregory Greenman , drbd-dev@lists.linbit.com, dev@openvswitch.org, Leon Romanovsky , Helge Deller , Hugh Dickins , James Smart , Anil S Keshavamurthy , Pravin B Shelar , Julian Anastasov , coreteam@netfilter.org, Veaceslav Falico , Yonghong Song , Namjae Jeon , linux-crypto@vger.kernel.org, Santosh Shilimkar , Ganapathi Bhat , linux-actions@lists.infradead.org, Simon Horman , Jaegeuk Kim , Mika Westerberg , Andrew Morton , OGAWA Hirofumi , Hao Luo , Theodore Ts'o , Stephen Boyd , Dennis Dalessandro , Florian Westphal , =?UTF-8?Q?Andreas_F=C3=A4rber?= , Jon Maloy , Vlad Yasevich , Anna Schumaker , Yehezkel Bernat , Haoyue Xu , Heiner Kallweit , linux-wireless@vger.kernel.org, Marcelo Ricardo Leitner , Rasmus Villemoes , linux-nvme@lists.infradead.org, Michal Januszewski , linux-mtd@lists.infradead.org, kasan-dev@googlegroups.com, Cong Wang , Thomas Sailer , Ajay Singh , Xiubo Li , Sagi Grimberg , Daniel Borkmann , Jonathan Corbet , linux-rdma@vger.kernel.org, lvs-devel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, "Naveen N . Rao" , Ilya Dryomov , Paolo Abeni , Pablo Neira Ayuso , Marco Elver , Kees Cook , Yury Norov , "James E . J . Bottomley" , Jamal Hadi Salim , KP Singh , Borislav Petkov , Keith Busch , Dan Williams , Mauro Carvalho Chehab , Franky Lin , Arend van Spriel , linux-ext4@vger.kernel.org, Wenpeng Liang , "Martin K . Petersen" , Xinming Hu , linux-stm32@st-md-mailman.stormreply.com, Jeff Layton , linux-xfs@vger.kernel.org, netdev@vger.kernel.org, Ying Xue , Manish Rangankar , "David S . Miller" , =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , Vignesh Raghavendra , Peter Zijlstra , "H . Peter Anvin" , Alexandre Torgue , Amitkumar Karwar , linux-mm@kvack.org, Andreas Dilger , Ayush Sawal , Andreas Noever , Jiri Pirko , linux-f2fs-devel@lists.sourceforge.net, Jack Wang , Steffen Klassert , rds-devel@oss.oracle.com, Herbert Xu , linux-scsi@vger.kernel.org, dccp@vger.kernel.org, Richard Weinberger , Russell King , SHA-cyfmac-dev-list@infineon.com, Ingo Molnar , Jakub Kicinski , John Fastabend , Maxime Coquelin , Manivannan Sadhasivam , Michael Jamet , Kalle Valo , Akinobu Mita , linux-block@vger.kernel.org, dmaengine@vger.kernel.org, Hannes Reinecke , Andy Shevchenko , Dmitry Vyukov , Jens Axboe , cake@lists.bufferbloat.net, brcm80211-dev-list.pdl@broadcom.com, Yishai Hadas , Hideaki YOSHIFUJI , linuxppc-dev@lists.ozlabs.org, David Ahern , Philipp Reisner , Stephen Hemminger , =?UTF-8?Q?Christoph_B=C3=B6hmwalder?= , Vinod Koul , tipc-discussion@lists.sourceforge.net, Thomas Graf , Johannes Berg , Sungjong Seo , Martin KaFai Lau Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Thu, Oct 6, 2022 at 6:47 AM Jason Gunthorpe wrote: > > On Wed, Oct 05, 2022 at 11:48:42PM +0200, Jason A. Donenfeld wrote: > > > index 14392c942f49..499a425a3379 100644 > > --- a/drivers/infiniband/hw/cxgb4/cm.c > > +++ b/drivers/infiniband/hw/cxgb4/cm.c > > @@ -734,7 +734,7 @@ static int send_connect(struct c4iw_ep *ep) > > &ep->com.remote_addr; > > int ret; > > enum chip_type adapter_type = ep->com.dev->rdev.lldi.adapter_type; > > - u32 isn = (prandom_u32() & ~7UL) - 1; > > + u32 isn = (get_random_u32() & ~7UL) - 1; > > Maybe this wants to be written as > > (prandom_max(U32_MAX >> 7) << 7) | 7 > > ? Holy smokes. Yea I guess maybe? It doesn't exactly gain anything or make the code clearer though, and is a little bit more magical than I'd like on a first pass. > > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > index fd9d7f2c4d64..a605cf66b83e 100644 > > --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > @@ -465,7 +465,7 @@ static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, > > goto err_qp; > > } > > > > - psn = prandom_u32() & 0xffffff; > > + psn = get_random_u32() & 0xffffff; > > prandom_max(0xffffff + 1) That'd work, but again it's not more clear. Authors here are going for a 24-bit number, and masking seems like a clear way to express that. Jason _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D7857C433F5 for ; Thu, 6 Oct 2022 13:06:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=zp1Dq9bsZup4ZtOq8yuVsS4vfqnhQE9+ha32fJA0z7Q=; b=YQC8+9EP8nJT7q rR6+96vVMt7c3uT6gOlIFJ5kmWDmjGFsVlDzUnH088gMG13apaUOlISyalim1Z70y3aC7mQ9DJQRz d079p5X+EF9b23EzLdPNavnSNeZk9hFSgin96Wy/XvginjhWZfx4q3JjZP7WRtZeLeHzawN1UP4Ui Knmm/5rW3diBDnP2eTCwSH/Bm6J/HaTY3JGMv9yfvI7/WOIuxxTcn03D+CH2J8fZmqRjO00lTP9+K d8Oa8GVieX/ja9yZacwki+6usJebIdsJ+1DvLOUgdZgpepqhyN6+N8Nv2+k7dJv74afEKi+EHaL62 UrAD1meQtCA+EiGFqMKA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ogQaC-002Wvu-3I; Thu, 06 Oct 2022 13:06:36 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ogQa8-002Wtx-R5; Thu, 06 Oct 2022 13:06:34 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 583F96199D; Thu, 6 Oct 2022 13:06:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5120C43142; Thu, 6 Oct 2022 13:06:31 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="AuLKX8Dr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1665061583; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pA8UwcaEH1EIaWBd+j+3kMQvSGVLEaIn/zvGprOy4bY=; b=AuLKX8DrexCaNcujtUc0wUOn6ZKYPxocCGUtsQ/xLo5zn9UlWE+se5mcJ1GdJKakmd68Cu zFNfO+H4CDBOx88U2U8iDMf5m8nlkrM8e7vsoJOojyzr28eChFXzvAHcN4AVzZnJW4K0oJ BdT+U8NEjgfOf1F1bQBHV1MnZd+JA8E= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id db77e84b (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 6 Oct 2022 13:06:22 +0000 (UTC) Received: by mail-vs1-f45.google.com with SMTP id 3so1924427vsh.5; Thu, 06 Oct 2022 06:06:15 -0700 (PDT) X-Gm-Message-State: ACrzQf2FdUVfoSNUdWKMK5lpcOZ6Bx8pvxN8k16upAS23nzdmPCr1lg2 7j0lpEHHBSIlYQDRdla85q0oAC5vWyYHh/ltT9U= X-Google-Smtp-Source: AMsMyM6FGZA2PC9dWVIDS+xWc3c+LtiQF9tezH4UggVMiZNKZxhMdBw8vpoz5pzuUaEI5CnlY9d0+H7OwJQF18qhy/U= X-Received: by 2002:a1f:e0c4:0:b0:3ab:191d:e135 with SMTP id x187-20020a1fe0c4000000b003ab191de135mr2112405vkg.41.1665061560263; Thu, 06 Oct 2022 06:06:00 -0700 (PDT) MIME-Version: 1.0 References: <20221005214844.2699-1-Jason@zx2c4.com> <20221005214844.2699-4-Jason@zx2c4.com> In-Reply-To: From: "Jason A. Donenfeld" Date: Thu, 6 Oct 2022 07:05:48 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 3/5] treewide: use get_random_u32() when possible To: Jason Gunthorpe Cc: linux-kernel@vger.kernel.org, Ajay Singh , Akinobu Mita , Alexandre Torgue , Amitkumar Karwar , Andreas Dilger , =?UTF-8?Q?Andreas_F=C3=A4rber?= , Andreas Noever , Andrew Lunn , Andrew Morton , Andrii Nakryiko , Andy Gospodarek , Andy Lutomirski , Andy Shevchenko , Anil S Keshavamurthy , Anna Schumaker , Arend van Spriel , Ayush Sawal , Borislav Petkov , Chao Yu , =?UTF-8?Q?Christoph_B=C3=B6hmwalder?= , Christoph Hellwig , Christophe Leroy , Chuck Lever , Claudiu Beznea , Cong Wang , Dan Williams , Daniel Borkmann , "Darrick J . Wong" , Dave Hansen , David Ahern , "David S . Miller" , Dennis Dalessandro , Dick Kennedy , Dmitry Vyukov , Eric Dumazet , Florian Westphal , Franky Lin , Ganapathi Bhat , Greg Kroah-Hartman , Gregory Greenman , "H . 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Donenfeld wrote: > > > index 14392c942f49..499a425a3379 100644 > > --- a/drivers/infiniband/hw/cxgb4/cm.c > > +++ b/drivers/infiniband/hw/cxgb4/cm.c > > @@ -734,7 +734,7 @@ static int send_connect(struct c4iw_ep *ep) > > &ep->com.remote_addr; > > int ret; > > enum chip_type adapter_type = ep->com.dev->rdev.lldi.adapter_type; > > - u32 isn = (prandom_u32() & ~7UL) - 1; > > + u32 isn = (get_random_u32() & ~7UL) - 1; > > Maybe this wants to be written as > > (prandom_max(U32_MAX >> 7) << 7) | 7 > > ? Holy smokes. Yea I guess maybe? It doesn't exactly gain anything or make the code clearer though, and is a little bit more magical than I'd like on a first pass. > > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > index fd9d7f2c4d64..a605cf66b83e 100644 > > --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > @@ -465,7 +465,7 @@ static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, > > goto err_qp; > > } > > > > - psn = prandom_u32() & 0xffffff; > > + psn = get_random_u32() & 0xffffff; > > prandom_max(0xffffff + 1) That'd work, but again it's not more clear. Authors here are going for a 24-bit number, and masking seems like a clear way to express that. Jason ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/ 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BA086C433F5 for ; Thu, 6 Oct 2022 15:03:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:Subject: Message-ID:Date:From:In-Reply-To:References:MIME-Version:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pA8UwcaEH1EIaWBd+j+3kMQvSGVLEaIn/zvGprOy4bY=; b=dt/W5gdhw7+wHb/F81TITHhJfc Up/VNIaHN2cFkOtf6SxiF8wAH95YNQyuvTRs8gB9qWV68J0RdF4v4GF+e3Xmi7IYAK3wj62jKUUxx Y3MKLzc/fRTAslM5L0PkIxYgiIPhRqy7n9o/m4EMi8s9A2MF/2GhBMYOG8RRu6Venz0SA5iHTUKjc vLxXFLe1jMVQJh5THrleLzCpkdUDqYyDbN9Br4WyTAr+YQKbU1Jko9z6cujsKBmhd6ojHn3+ldakF ebVn3HvAK+/cP3X2sWVZYDB3sDS7f/KKJEKEeD9Ygdp4fc8JHhH9ySFecSvLu12Jus6905EaUgOn/ dTBrjcjw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ogSOt-003CVW-HT; Thu, 06 Oct 2022 15:03:03 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ogQa8-002Wtx-R5; Thu, 06 Oct 2022 13:06:34 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 583F96199D; Thu, 6 Oct 2022 13:06:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5120C43142; Thu, 6 Oct 2022 13:06:31 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="AuLKX8Dr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1665061583; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pA8UwcaEH1EIaWBd+j+3kMQvSGVLEaIn/zvGprOy4bY=; b=AuLKX8DrexCaNcujtUc0wUOn6ZKYPxocCGUtsQ/xLo5zn9UlWE+se5mcJ1GdJKakmd68Cu zFNfO+H4CDBOx88U2U8iDMf5m8nlkrM8e7vsoJOojyzr28eChFXzvAHcN4AVzZnJW4K0oJ BdT+U8NEjgfOf1F1bQBHV1MnZd+JA8E= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id db77e84b (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 6 Oct 2022 13:06:22 +0000 (UTC) Received: by mail-vs1-f45.google.com with SMTP id 3so1924427vsh.5; Thu, 06 Oct 2022 06:06:15 -0700 (PDT) X-Gm-Message-State: ACrzQf2FdUVfoSNUdWKMK5lpcOZ6Bx8pvxN8k16upAS23nzdmPCr1lg2 7j0lpEHHBSIlYQDRdla85q0oAC5vWyYHh/ltT9U= X-Google-Smtp-Source: AMsMyM6FGZA2PC9dWVIDS+xWc3c+LtiQF9tezH4UggVMiZNKZxhMdBw8vpoz5pzuUaEI5CnlY9d0+H7OwJQF18qhy/U= X-Received: by 2002:a1f:e0c4:0:b0:3ab:191d:e135 with SMTP id x187-20020a1fe0c4000000b003ab191de135mr2112405vkg.41.1665061560263; Thu, 06 Oct 2022 06:06:00 -0700 (PDT) MIME-Version: 1.0 References: <20221005214844.2699-1-Jason@zx2c4.com> <20221005214844.2699-4-Jason@zx2c4.com> In-Reply-To: From: "Jason A. Donenfeld" Date: Thu, 6 Oct 2022 07:05:48 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 3/5] treewide: use get_random_u32() when possible To: Jason Gunthorpe Cc: linux-kernel@vger.kernel.org, Ajay Singh , Akinobu Mita , Alexandre Torgue , Amitkumar Karwar , Andreas Dilger , =?UTF-8?Q?Andreas_F=C3=A4rber?= , Andreas Noever , Andrew Lunn , Andrew Morton , Andrii Nakryiko , Andy Gospodarek , Andy Lutomirski , Andy Shevchenko , Anil S Keshavamurthy , Anna Schumaker , Arend van Spriel , Ayush Sawal , Borislav Petkov , Chao Yu , =?UTF-8?Q?Christoph_B=C3=B6hmwalder?= , Christoph Hellwig , Christophe Leroy , Chuck Lever , Claudiu Beznea , Cong Wang , Dan Williams , Daniel Borkmann , "Darrick J . Wong" , Dave Hansen , David Ahern , "David S . Miller" , Dennis Dalessandro , Dick Kennedy , Dmitry Vyukov , Eric Dumazet , Florian Westphal , Franky Lin , Ganapathi Bhat , Greg Kroah-Hartman , Gregory Greenman , "H . 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Donenfeld wrote: > > > index 14392c942f49..499a425a3379 100644 > > --- a/drivers/infiniband/hw/cxgb4/cm.c > > +++ b/drivers/infiniband/hw/cxgb4/cm.c > > @@ -734,7 +734,7 @@ static int send_connect(struct c4iw_ep *ep) > > &ep->com.remote_addr; > > int ret; > > enum chip_type adapter_type = ep->com.dev->rdev.lldi.adapter_type; > > - u32 isn = (prandom_u32() & ~7UL) - 1; > > + u32 isn = (get_random_u32() & ~7UL) - 1; > > Maybe this wants to be written as > > (prandom_max(U32_MAX >> 7) << 7) | 7 > > ? Holy smokes. Yea I guess maybe? It doesn't exactly gain anything or make the code clearer though, and is a little bit more magical than I'd like on a first pass. > > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > index fd9d7f2c4d64..a605cf66b83e 100644 > > --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > @@ -465,7 +465,7 @@ static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, > > goto err_qp; > > } > > > > - psn = prandom_u32() & 0xffffff; > > + psn = get_random_u32() & 0xffffff; > > prandom_max(0xffffff + 1) That'd work, but again it's not more clear. Authors here are going for a 24-bit number, and masking seems like a clear way to express that. Jason 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 45C8DC433F5 for ; Fri, 7 Oct 2022 04:54:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 93F7010E919; Fri, 7 Oct 2022 04:54:08 +0000 (UTC) Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by gabe.freedesktop.org (Postfix) with ESMTPS id 69B7410E3BD for ; Thu, 6 Oct 2022 13:06:35 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 0182EB81FCF for ; Thu, 6 Oct 2022 13:06:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DB2FC433D7 for ; Thu, 6 Oct 2022 13:06:32 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="AuLKX8Dr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1665061583; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pA8UwcaEH1EIaWBd+j+3kMQvSGVLEaIn/zvGprOy4bY=; b=AuLKX8DrexCaNcujtUc0wUOn6ZKYPxocCGUtsQ/xLo5zn9UlWE+se5mcJ1GdJKakmd68Cu zFNfO+H4CDBOx88U2U8iDMf5m8nlkrM8e7vsoJOojyzr28eChFXzvAHcN4AVzZnJW4K0oJ BdT+U8NEjgfOf1F1bQBHV1MnZd+JA8E= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id d92412b6 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO) for ; Thu, 6 Oct 2022 13:06:23 +0000 (UTC) Received: by mail-vk1-f181.google.com with SMTP id g85so766731vkf.10 for ; Thu, 06 Oct 2022 06:06:22 -0700 (PDT) X-Gm-Message-State: ACrzQf0KT3VyZTZ8tLrfk6QX0FqERt3mY2TFi0pzveI7J0bXQA21r/2C 2iKv0xleBnHFqp/kxcJqOMFBdstYqobbFPOwNu8= X-Google-Smtp-Source: AMsMyM6FGZA2PC9dWVIDS+xWc3c+LtiQF9tezH4UggVMiZNKZxhMdBw8vpoz5pzuUaEI5CnlY9d0+H7OwJQF18qhy/U= X-Received: by 2002:a1f:e0c4:0:b0:3ab:191d:e135 with SMTP id x187-20020a1fe0c4000000b003ab191de135mr2112405vkg.41.1665061560263; Thu, 06 Oct 2022 06:06:00 -0700 (PDT) MIME-Version: 1.0 References: <20221005214844.2699-1-Jason@zx2c4.com> <20221005214844.2699-4-Jason@zx2c4.com> In-Reply-To: From: "Jason A. Donenfeld" Date: Thu, 6 Oct 2022 07:05:48 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 3/5] treewide: use get_random_u32() when possible To: Jason Gunthorpe Content-Type: text/plain; charset="UTF-8" X-Mailman-Approved-At: Fri, 07 Oct 2022 04:54:02 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Lunn , "Darrick J . Wong" , Ulf Hansson , dri-devel@lists.freedesktop.org, Andrii Nakryiko , Hans Verkuil , linux-sctp@vger.kernel.org, "Md . 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Peter Anvin" , Alexandre Torgue , Amitkumar Karwar , linux-mm@kvack.org, Andreas Dilger , Ayush Sawal , Andreas Noever , Jiri Pirko , linux-f2fs-devel@lists.sourceforge.net, Jack Wang , Steffen Klassert , rds-devel@oss.oracle.com, Herbert Xu , linux-scsi@vger.kernel.org, dccp@vger.kernel.org, Richard Weinberger , Russell King , Jaehoon Chung , SHA-cyfmac-dev-list@infineon.com, Ingo Molnar , Jakub Kicinski , John Fastabend , Maxime Coquelin , Manivannan Sadhasivam , Michael Jamet , Kalle Valo , Chao Yu , Akinobu Mita , linux-block@vger.kernel.org, dmaengine@vger.kernel.org, Hannes Reinecke , Andy Shevchenko , Dmitry Vyukov , Jens Axboe , cake@lists.bufferbloat.net, brcm80211-dev-list.pdl@broadcom.com, Yishai Hadas , Hideaki YOSHIFUJI , linuxppc-dev@lists.ozlabs.org, David Ahern , Philipp Reisner , Stephen Hemminger , =?UTF-8?Q?Christoph_B=C3=B6hmwalder?= , Vinod Koul , tipc-discussion@lists.sourceforge.net, Thomas Graf , Johannes Berg , Sungjong Seo , Martin KaFai Lau Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, Oct 6, 2022 at 6:47 AM Jason Gunthorpe wrote: > > On Wed, Oct 05, 2022 at 11:48:42PM +0200, Jason A. Donenfeld wrote: > > > index 14392c942f49..499a425a3379 100644 > > --- a/drivers/infiniband/hw/cxgb4/cm.c > > +++ b/drivers/infiniband/hw/cxgb4/cm.c > > @@ -734,7 +734,7 @@ static int send_connect(struct c4iw_ep *ep) > > &ep->com.remote_addr; > > int ret; > > enum chip_type adapter_type = ep->com.dev->rdev.lldi.adapter_type; > > - u32 isn = (prandom_u32() & ~7UL) - 1; > > + u32 isn = (get_random_u32() & ~7UL) - 1; > > Maybe this wants to be written as > > (prandom_max(U32_MAX >> 7) << 7) | 7 > > ? Holy smokes. Yea I guess maybe? It doesn't exactly gain anything or make the code clearer though, and is a little bit more magical than I'd like on a first pass. > > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > index fd9d7f2c4d64..a605cf66b83e 100644 > > --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > @@ -465,7 +465,7 @@ static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, > > goto err_qp; > > } > > > > - psn = prandom_u32() & 0xffffff; > > + psn = get_random_u32() & 0xffffff; > > prandom_max(0xffffff + 1) That'd work, but again it's not more clear. Authors here are going for a 24-bit number, and masking seems like a clear way to express that. Jason 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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DDD15C433F5 for ; Thu, 6 Oct 2022 22:41:20 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Mk5yR31Sfz3dxd for ; Fri, 7 Oct 2022 09:41:19 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=zx2c4.com header.i=@zx2c4.com header.a=rsa-sha256 header.s=20210105 header.b=olBPwSHh; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=srs0=tiop=2h=zx2c4.com=jason@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=zx2c4.com header.i=@zx2c4.com header.a=rsa-sha256 header.s=20210105 header.b=olBPwSHh; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4MjsCD5p42z2yP8 for ; Fri, 7 Oct 2022 00:06:32 +1100 (AEDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9F3866199B for ; Thu, 6 Oct 2022 13:06:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D526DC433B5 for ; Thu, 6 Oct 2022 13:06:28 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="olBPwSHh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1665061581; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pA8UwcaEH1EIaWBd+j+3kMQvSGVLEaIn/zvGprOy4bY=; b=olBPwSHhemo7SqJZrD/ohuL/GJOH6P8oRtQiCgFrh6JtzQ3eHzKBrfOp5rqZEljamNPYtM d3tDiNWyJdIguKFPG/fKCfGFr/l1S51a3Y0tUyLoghfcpwMwwLwwWXTvh90Uc/SDuFMJPq nWucyfXmWaSqVQulBeew44uvASWmLeg= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 63b3f553 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO) for ; Thu, 6 Oct 2022 13:06:20 +0000 (UTC) Received: by mail-vs1-f48.google.com with SMTP id k6so1906061vsc.8 for ; Thu, 06 Oct 2022 06:06:15 -0700 (PDT) X-Gm-Message-State: ACrzQf0OrnEk0FlmtaabEDW4Tkdl48aCh/tfuL/pH5hOp2TRmYHveH9I 7+YcR5DV/8PG+vJpUZ/gusQHROhjG4q3Hp06kj8= X-Google-Smtp-Source: AMsMyM6FGZA2PC9dWVIDS+xWc3c+LtiQF9tezH4UggVMiZNKZxhMdBw8vpoz5pzuUaEI5CnlY9d0+H7OwJQF18qhy/U= X-Received: by 2002:a1f:e0c4:0:b0:3ab:191d:e135 with SMTP id x187-20020a1fe0c4000000b003ab191de135mr2112405vkg.41.1665061560263; Thu, 06 Oct 2022 06:06:00 -0700 (PDT) MIME-Version: 1.0 References: <20221005214844.2699-1-Jason@zx2c4.com> <20221005214844.2699-4-Jason@zx2c4.com> In-Reply-To: From: "Jason A. Donenfeld" Date: Thu, 6 Oct 2022 07:05:48 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 3/5] treewide: use get_random_u32() when possible To: Jason Gunthorpe Content-Type: text/plain; charset="UTF-8" X-Mailman-Approved-At: Fri, 07 Oct 2022 09:35:18 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Lunn , "Darrick J . Wong" , Ulf Hansson , dri-devel@lists.freedesktop.org, Andrii Nakryiko , Hans Verkuil , linux-sctp@vger.kernel.org, "Md . 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Peter Anvin" , Alexandre Torgue , Amitkumar Karwar , linux-mm@kvack.org, Andreas Dilger , Ayush Sawal , Andreas Noever , Jiri Pirko , linux-f2fs-devel@lists.sourceforge.net, Jack Wang , Steffen Klassert , rds-devel@oss.oracle.com, Herbert Xu , linux-scsi@vger.kernel.org, dccp@vger.kernel.org, Richard Weinberger , Russell King , Jaehoon Chung , SHA-cyfmac-dev-list@infineon.com, Ingo Molnar , Jakub Kicinski , John Fastabend , Maxime Coquelin , Manivannan Sadhasivam , Michael Jamet , Kalle Valo , Chao Yu , Akinobu Mita , linux-block@vger.kernel.org, dmaengine@vger.kernel.org, Hannes Reinecke , Andy Shevchenko , Dmitry Vyukov , Jens Axboe , cake@lists.bufferbloat.net, brcm80211-dev-list.pdl@broadcom.com, Yishai Hadas , Hideaki YOSHIFUJI , linuxppc-dev@lists.ozlabs.org, David Ahern , Philipp Reisner , Stephen Hemminger , =?UTF-8?Q?Christoph_B=C3=B6hmwalder?= , Vinod Koul , tipc-discussion@lists.sourceforge.net, Thomas Graf , Johannes Berg , Sungjong Seo , Martin KaFai Lau Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Oct 6, 2022 at 6:47 AM Jason Gunthorpe wrote: > > On Wed, Oct 05, 2022 at 11:48:42PM +0200, Jason A. Donenfeld wrote: > > > index 14392c942f49..499a425a3379 100644 > > --- a/drivers/infiniband/hw/cxgb4/cm.c > > +++ b/drivers/infiniband/hw/cxgb4/cm.c > > @@ -734,7 +734,7 @@ static int send_connect(struct c4iw_ep *ep) > > &ep->com.remote_addr; > > int ret; > > enum chip_type adapter_type = ep->com.dev->rdev.lldi.adapter_type; > > - u32 isn = (prandom_u32() & ~7UL) - 1; > > + u32 isn = (get_random_u32() & ~7UL) - 1; > > Maybe this wants to be written as > > (prandom_max(U32_MAX >> 7) << 7) | 7 > > ? Holy smokes. Yea I guess maybe? It doesn't exactly gain anything or make the code clearer though, and is a little bit more magical than I'd like on a first pass. > > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > index fd9d7f2c4d64..a605cf66b83e 100644 > > --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > @@ -465,7 +465,7 @@ static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, > > goto err_qp; > > } > > > > - psn = prandom_u32() & 0xffffff; > > + psn = get_random_u32() & 0xffffff; > > prandom_max(0xffffff + 1) That'd work, but again it's not more clear. Authors here are going for a 24-bit number, and masking seems like a clear way to express that. Jason From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jason A. Donenfeld via dev" Subject: Re: [PATCH v1 3/5] treewide: use get_random_u32() when possible Date: Thu, 6 Oct 2022 07:05:48 -0600 Message-ID: References: <20221005214844.2699-1-Jason@zx2c4.com> <20221005214844.2699-4-Jason@zx2c4.com> Reply-To: "Jason A. Donenfeld" Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 900CC40C4C DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 7CB1D40223 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 4355240C2B DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 218DA40223 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1665061581; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pA8UwcaEH1EIaWBd+j+3kMQvSGVLEaIn/zvGprOy4bY=; b=olBPwSHhemo7SqJZrD/ohuL/GJOH6P8oRtQiCgFrh6JtzQ3eHzKBrfOp5rqZEljamNPYtM d3tDiNWyJdIguKFPG/fKCfGFr/l1S51a3Y0tUyLoghfcpwMwwLwwWXTvh90Uc/SDuFMJPq nWucyfXmWaSqVQulBeew44uvASWmLeg= In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: ovs-dev-bounces-yBygre7rU0TnMu66kgdUjQ@public.gmane.org Sender: "dev" To: Jason Gunthorpe Cc: Andrew Lunn , "Darrick J . Wong" , Ulf Hansson , dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, Andrii Nakryiko , Hans Verkuil , linux-sctp-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "Md . Haris Iqbal" , Miquel Raynal , Christoph Hellwig , Andy Gospodarek , Sergey Matyukevich , Rohit Maheshwari , Michael Ellerman , ceph-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Christophe Leroy , Jozsef Kadlecsik , Nilesh Javali , Jean-Paul Roubelat , Dick Kennedy , Jay Vosburgh , Potnuri Bharat Teja , Vinay Kumar Yadav , linux-nfs@vg On Thu, Oct 6, 2022 at 6:47 AM Jason Gunthorpe wrote: > > On Wed, Oct 05, 2022 at 11:48:42PM +0200, Jason A. Donenfeld wrote: > > > index 14392c942f49..499a425a3379 100644 > > --- a/drivers/infiniband/hw/cxgb4/cm.c > > +++ b/drivers/infiniband/hw/cxgb4/cm.c > > @@ -734,7 +734,7 @@ static int send_connect(struct c4iw_ep *ep) > > &ep->com.remote_addr; > > int ret; > > enum chip_type adapter_type = ep->com.dev->rdev.lldi.adapter_type; > > - u32 isn = (prandom_u32() & ~7UL) - 1; > > + u32 isn = (get_random_u32() & ~7UL) - 1; > > Maybe this wants to be written as > > (prandom_max(U32_MAX >> 7) << 7) | 7 > > ? Holy smokes. Yea I guess maybe? It doesn't exactly gain anything or make the code clearer though, and is a little bit more magical than I'd like on a first pass. > > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > index fd9d7f2c4d64..a605cf66b83e 100644 > > --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > > @@ -465,7 +465,7 @@ static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, > > goto err_qp; > > } > > > > - psn = prandom_u32() & 0xffffff; > > + psn = get_random_u32() & 0xffffff; > > prandom_max(0xffffff + 1) That'd work, but again it's not more clear. Authors here are going for a 24-bit number, and masking seems like a clear way to express that. Jason