| Message ID | 20221005214844.2699-1-Jason@zx2c4.com |
|---|---|
| Headers | show |
| Series | treewide cleanup of random integer usage | expand |
On Thu, Oct 06, 2022 at 06:33:15AM -0600, Jason A. Donenfeld wrote: > On Thu, Oct 06, 2022 at 10:43:31AM +0200, Jan Kara wrote: ... > > The code here is effectively doing the > > > > parent_group = prandom_u32_max(ngroups); > > > > Similarly here we can use prandom_u32_max(ngroups) like: > > > > if (qstr) { > > ... > > parent_group = hinfo.hash % ngroups; > > } else > > parent_group = prandom_u32_max(ngroups); > > Nice catch. I'll move these to patch #1. I believe coccinelle is able to handle this kind of code as well, so Kees' proposal to use it seems more plausible since it's less error prone and more flexible / powerful.
On Thu, Oct 6, 2022 at 7:01 AM Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > > On Thu, Oct 06, 2022 at 06:33:15AM -0600, Jason A. Donenfeld wrote: > > On Thu, Oct 06, 2022 at 10:43:31AM +0200, Jan Kara wrote: > > ... > > > > The code here is effectively doing the > > > > > > parent_group = prandom_u32_max(ngroups); > > > > > > Similarly here we can use prandom_u32_max(ngroups) like: > > > > > > if (qstr) { > > > ... > > > parent_group = hinfo.hash % ngroups; > > > } else > > > parent_group = prandom_u32_max(ngroups); > > > > Nice catch. I'll move these to patch #1. > > I believe coccinelle is able to handle this kind of code as well I'd be extremely surprised. The details were kind of non obvious. I just spent a decent amount of time manually checking those blocks, to make sure we didn't wind up with different behavior, given the variable reuse. Jason
On Thu, Oct 06, 2022 at 07:05:48AM -0600, Jason A. Donenfeld wrote: > > > 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. vs just asking directly for a 24 bit number? Jason
Hi folks, This is a five part treewide cleanup of random integer handling. The rules for random integers are: - If you want a secure or an insecure random u64, use get_random_u64(). - If you want a secure or an insecure random u32, use get_random_u32(). * The old function prandom_u32() has been deprecated for a while now and is just a wrapper around get_random_u32(). - If you want a secure or an insecure random u16, use get_random_u16(). - If you want a secure or an insecure random u8, use get_random_u8(). - If you want secure or insecure random bytes, use get_random_bytes(). * The old function prandom_bytes() has been deprecated for a while now and has long been a wrapper around get_random_bytes(). - If you want a non-uniform random u32, u16, or u8 bounded by a certain open interval maximum, use prandom_u32_max(). * I say "non-uniform", because it doesn't do any rejection sampling or divisions. Hence, it stays within the prandom_* namespace. These rules ought to be applied uniformly, so that we can clean up the deprecated functions, and earn the benefits of using the modern functions. In particular, in addition to the boring substitutions, this patchset accomplishes a few nice effects: - By using prandom_u32_max() with an upper-bound that the compiler can prove at compile-time is ≤65536 or ≤256, internally get_random_u16() or get_random_u8() is used, which wastes fewer batched random bytes, and hence has higher throughput. - By using prandom_u32_max() instead of %, when the upper-bound is not a constant, division is still avoided, because prandom_u32_max() uses a faster multiplication-based trick instead. - By using get_random_u16() or get_random_u8() in cases where the return value is intended to indeed be a u16 or a u8, we waste fewer batched random bytes, and hence have higher throughput. So, based on those rules and benefits from following them, this patchset breaks down into the following five steps: 1) Replace `prandom_u32() % max` and variants thereof with prandom_u32_max(max). 2) Replace `(type)get_random_u32()` and variants thereof with get_random_u16() or get_random_u8(). I took the pains to actually look and see what every lvalue type was across the entire tree. 3) Replace remaining deprecated uses of prandom_u32() with get_random_u32(). 4) Replace remaining deprecated uses of prandom_bytes() with get_random_bytes(). 5) Remove the deprecated and now-unused prandom_u32() and prandom_bytes() inline wrapper functions. I was thinking of taking this through my random.git tree (on which this series is currently based) and submitting it near the end of the merge window, or waiting for the very end of the 6.1 cycle when there will be the fewest new patches brewing. If somebody with some treewide-cleanup experience might share some wisdom about what the best timing usually winds up being, I'm all ears. I've CC'd get_maintainers.pl, which is a pretty big list. Probably some portion of those are going to bounce, too, and everytime you reply to this thread, you'll have to deal with a bunch of bounces coming immediately after. And a recipient list this big will probably dock my email domain's spam reputation, at least temporarily. Sigh. I think that's just how it goes with treewide cleanups though. Again, let me know if I'm doing it wrong. Please take a look! Thanks, Jason Cc: Ajay Singh <ajay.kathat@microchip.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: Amitkumar Karwar <amitkarwar@gmail.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Andreas Färber <afaerber@suse.de> Cc: Andreas Noever <andreas.noever@gmail.com> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Andy Gospodarek <andy@greyhouse.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Anna Schumaker <anna@kernel.org> Cc: Arend van Spriel <aspriel@gmail.com> Cc: Ayush Sawal <ayush.sawal@chelsio.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Chao Yu <chao@kernel.org> Cc: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Claudiu Beznea <claudiu.beznea@microchip.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Ahern <dsahern@kernel.org> Cc: David S. Miller <davem@davemloft.net> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Dick Kennedy <dick.kennedy@broadcom.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Florian Westphal <fw@strlen.de> Cc: Franky Lin <franky.lin@broadcom.com> Cc: Ganapathi Bhat <ganapathi017@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Gregory Greenman <gregory.greenman@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Hans Verkuil <hverkuil@xs4all.nl> Cc: Hante Meuleman <hante.meuleman@broadcom.com> Cc: Hao Luo <haoluo@google.com> Cc: Haoyue Xu <xuhaoyue1@hisilicon.com> Cc: Heiner Kallweit <hkallweit1@gmail.com> Cc: Helge Deller <deller@gmx.de> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: Hugh Dickins <hughd@google.com> Cc: Igor Mitsyanko <imitsyanko@quantenna.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jack Wang <jinpu.wang@ionos.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Jaehoon Chung <jh80.chung@samsung.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: James E.J. Bottomley <jejb@linux.ibm.com> Cc: James Smart <james.smart@broadcom.com> Cc: Jan Kara <jack@suse.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jay Vosburgh <j.vosburgh@gmail.com> Cc: Jean-Paul Roubelat <jpr@f6fbb.org> Cc: Jeff Layton <jlayton@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Jiri Pirko <jiri@resnulli.us> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: John Fastabend <john.fastabend@gmail.com> Cc: John Stultz <jstultz@google.com> Cc: Jon Maloy <jmaloy@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jozsef Kadlecsik <kadlec@netfilter.org> Cc: Julian Anastasov <ja@ssi.bg> Cc: KP Singh <kpsingh@kernel.org> Cc: Kalle Valo <kvalo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Keith Busch <kbusch@kernel.org> Cc: Lars Ellenberg <lars.ellenberg@linbit.com> Cc: Leon Romanovsky <leon@kernel.org> Cc: Manish Rangankar <mrangankar@marvell.com> Cc: Manivannan Sadhasivam <mani@kernel.org> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Cc: Marco Elver <elver@google.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Md. Haris Iqbal <haris.iqbal@ionos.com> Cc: Michael Chan <michael.chan@broadcom.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michael Jamet <michael.jamet@intel.com> Cc: Michal Januszewski <spock@gentoo.org> Cc: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Miquel Raynal <miquel.raynal@bootlin.com> Cc: Namjae Jeon <linkinjeon@kernel.org> Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Nilesh Javali <njavali@marvell.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: Potnuri Bharat Teja <bharat@chelsio.com> Cc: Pravin B Shelar <pshelar@ovn.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Richard Weinberger <richard@nod.at> Cc: Rohit Maheshwari <rohitm@chelsio.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com> Cc: Sergey Matyukevich <geomatsi@gmail.com> Cc: Sharvari Harisangam <sharvari.harisangam@nxp.com> Cc: Simon Horman <horms@verge.net.au> Cc: Song Liu <song@kernel.org> Cc: Stanislav Fomichev <sdf@google.com> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Stephen Boyd <sboyd@kernel.org> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Sungjong Seo <sj1557.seo@samsung.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Graf <tgraf@suug.ch> Cc: Thomas Sailer <t.sailer@alumni.ethz.ch> Cc: Toke Høiland-Jørgensen <toke@toke.dk> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Varun Prakash <varun@chelsio.com> Cc: Veaceslav Falico <vfalico@gmail.com> Cc: Vignesh Raghavendra <vigneshr@ti.com> Cc: Vinay Kumar Yadav <vinay.yadav@chelsio.com> Cc: Vinod Koul <vkoul@kernel.org> Cc: Vlad Yasevich <vyasevich@gmail.com> Cc: Wenpeng Liang <liangwenpeng@huawei.com> Cc: Xinming Hu <huxinming820@gmail.com> Cc: Xiubo Li <xiubli@redhat.com> Cc: Yehezkel Bernat <YehezkelShB@gmail.com> Cc: Ying Xue <ying.xue@windriver.com> Cc: Yishai Hadas <yishaih@nvidia.com> Cc: Yonghong Song <yhs@fb.com> Cc: Yury Norov <yury.norov@gmail.com> Cc: brcm80211-dev-list.pdl@broadcom.com Cc: cake@lists.bufferbloat.net Cc: ceph-devel@vger.kernel.org Cc: coreteam@netfilter.org Cc: dccp@vger.kernel.org Cc: dev@openvswitch.org Cc: dmaengine@vger.kernel.org Cc: drbd-dev@lists.linbit.com Cc: dri-devel@lists.freedesktop.org Cc: kasan-dev@googlegroups.com Cc: linux-actions@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-block@vger.kernel.org Cc: linux-crypto@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-ext4@vger.kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net Cc: linux-fbdev@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-hams@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-mmc@vger.kernel.org Cc: linux-mtd@lists.infradead.org Cc: linux-nfs@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: linux-raid@vger.kernel.org Cc: linux-rdma@vger.kernel.org Cc: linux-scsi@vger.kernel.org Cc: linux-sctp@vger.kernel.org Cc: linux-stm32@st-md-mailman.stormreply.com Cc: linux-usb@vger.kernel.org Cc: linux-wireless@vger.kernel.org Cc: linux-xfs@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: lvs-devel@vger.kernel.org Cc: netdev@vger.kernel.org Cc: netfilter-devel@vger.kernel.org Cc: rds-devel@oss.oracle.com Cc: SHA-cyfmac-dev-list@infineon.com Cc: target-devel@vger.kernel.org Cc: tipc-discussion@lists.sourceforge.net Jason A. Donenfeld (5): treewide: use prandom_u32_max() when possible treewide: use get_random_{u8,u16}() when possible treewide: use get_random_u32() when possible treewide: use get_random_bytes when possible prandom: remove unused functions Documentation/networking/filter.rst | 2 +- arch/powerpc/crypto/crc-vpmsum_test.c | 2 +- arch/x86/mm/pat/cpa-test.c | 4 +- block/blk-crypto-fallback.c | 2 +- crypto/async_tx/raid6test.c | 2 +- crypto/testmgr.c | 94 +++++++++---------- drivers/block/drbd/drbd_receiver.c | 4 +- drivers/dma/dmatest.c | 2 +- drivers/infiniband/core/cma.c | 2 +- drivers/infiniband/hw/cxgb4/cm.c | 4 +- drivers/infiniband/hw/cxgb4/id_table.c | 4 +- drivers/infiniband/hw/hfi1/tid_rdma.c | 2 +- drivers/infiniband/hw/hns/hns_roce_ah.c | 5 +- drivers/infiniband/hw/mlx4/mad.c | 2 +- drivers/infiniband/ulp/ipoib/ipoib_cm.c | 2 +- drivers/infiniband/ulp/rtrs/rtrs-clt.c | 3 +- drivers/md/raid5-cache.c | 2 +- drivers/media/common/v4l2-tpg/v4l2-tpg-core.c | 2 +- .../media/test-drivers/vivid/vivid-radio-rx.c | 4 +- drivers/mmc/core/core.c | 4 +- drivers/mmc/host/dw_mmc.c | 2 +- drivers/mtd/nand/raw/nandsim.c | 8 +- drivers/mtd/tests/mtd_nandecctest.c | 12 +-- drivers/mtd/tests/speedtest.c | 2 +- drivers/mtd/tests/stresstest.c | 19 +--- drivers/mtd/ubi/debug.c | 2 +- drivers/mtd/ubi/debug.h | 6 +- drivers/net/bonding/bond_main.c | 2 +- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 +- drivers/net/ethernet/broadcom/cnic.c | 5 +- .../chelsio/inline_crypto/chtls/chtls_cm.c | 4 +- .../chelsio/inline_crypto/chtls/chtls_io.c | 4 +- drivers/net/ethernet/rocker/rocker_main.c | 8 +- drivers/net/hamradio/baycom_epp.c | 2 +- drivers/net/hamradio/hdlcdrv.c | 2 +- drivers/net/hamradio/yam.c | 2 +- drivers/net/phy/at803x.c | 2 +- drivers/net/wireguard/selftest/allowedips.c | 16 ++-- .../broadcom/brcm80211/brcmfmac/p2p.c | 2 +- .../net/wireless/intel/iwlwifi/mvm/mac-ctxt.c | 2 +- .../net/wireless/marvell/mwifiex/cfg80211.c | 4 +- .../wireless/microchip/wilc1000/cfg80211.c | 2 +- .../net/wireless/quantenna/qtnfmac/cfg80211.c | 2 +- drivers/nvme/common/auth.c | 2 +- drivers/scsi/cxgbi/cxgb4i/cxgb4i.c | 4 +- drivers/scsi/fcoe/fcoe_ctlr.c | 4 +- drivers/scsi/lpfc/lpfc_hbadisc.c | 6 +- drivers/scsi/qedi/qedi_main.c | 2 +- drivers/target/iscsi/cxgbit/cxgbit_cm.c | 2 +- drivers/thunderbolt/xdomain.c | 2 +- drivers/video/fbdev/uvesafb.c | 2 +- fs/ceph/inode.c | 2 +- fs/ceph/mdsmap.c | 2 +- fs/exfat/inode.c | 2 +- fs/ext2/ialloc.c | 2 +- fs/ext4/ialloc.c | 4 +- fs/ext4/ioctl.c | 4 +- fs/ext4/mmp.c | 2 +- fs/ext4/super.c | 7 +- fs/f2fs/gc.c | 2 +- fs/f2fs/namei.c | 2 +- fs/f2fs/segment.c | 8 +- fs/fat/inode.c | 2 +- fs/nfsd/nfs4state.c | 4 +- fs/ubifs/debug.c | 10 +- fs/ubifs/journal.c | 2 +- fs/ubifs/lpt_commit.c | 14 +-- fs/ubifs/tnc_commit.c | 2 +- fs/xfs/libxfs/xfs_alloc.c | 2 +- fs/xfs/libxfs/xfs_ialloc.c | 4 +- fs/xfs/xfs_error.c | 2 +- fs/xfs/xfs_icache.c | 2 +- fs/xfs/xfs_log.c | 2 +- include/linux/prandom.h | 12 --- include/net/netfilter/nf_queue.h | 2 +- include/net/red.h | 2 +- include/net/sock.h | 2 +- kernel/kcsan/selftest.c | 4 +- kernel/time/clocksource.c | 2 +- lib/fault-inject.c | 2 +- lib/find_bit_benchmark.c | 4 +- lib/random32.c | 4 +- lib/reed_solomon/test_rslib.c | 12 +-- lib/sbitmap.c | 4 +- lib/test_fprobe.c | 2 +- lib/test_kprobes.c | 2 +- lib/test_list_sort.c | 2 +- lib/test_objagg.c | 2 +- lib/test_rhashtable.c | 6 +- lib/test_vmalloc.c | 19 +--- lib/uuid.c | 2 +- mm/shmem.c | 2 +- net/802/garp.c | 2 +- net/802/mrp.c | 2 +- net/ceph/mon_client.c | 2 +- net/ceph/osd_client.c | 2 +- net/core/neighbour.c | 2 +- net/core/pktgen.c | 47 +++++----- net/core/stream.c | 2 +- net/dccp/ipv4.c | 4 +- net/ipv4/datagram.c | 2 +- net/ipv4/igmp.c | 6 +- net/ipv4/inet_connection_sock.c | 2 +- net/ipv4/inet_hashtables.c | 2 +- net/ipv4/ip_output.c | 2 +- net/ipv4/route.c | 2 +- net/ipv4/tcp_cdg.c | 2 +- net/ipv4/tcp_ipv4.c | 4 +- net/ipv4/udp.c | 2 +- net/ipv6/addrconf.c | 8 +- net/ipv6/ip6_flowlabel.c | 2 +- net/ipv6/mcast.c | 10 +- net/ipv6/output_core.c | 2 +- net/mac80211/rc80211_minstrel_ht.c | 2 +- net/mac80211/scan.c | 2 +- net/netfilter/ipvs/ip_vs_conn.c | 2 +- net/netfilter/ipvs/ip_vs_twos.c | 4 +- net/netfilter/nf_nat_core.c | 4 +- net/netfilter/xt_statistic.c | 2 +- net/openvswitch/actions.c | 2 +- net/packet/af_packet.c | 2 +- net/rds/bind.c | 2 +- net/sched/act_gact.c | 2 +- net/sched/act_sample.c | 2 +- net/sched/sch_cake.c | 8 +- net/sched/sch_netem.c | 22 ++--- net/sched/sch_pie.c | 2 +- net/sched/sch_sfb.c | 2 +- net/sctp/socket.c | 4 +- net/sunrpc/auth_gss/gss_krb5_wrap.c | 4 +- net/sunrpc/cache.c | 2 +- net/sunrpc/xprt.c | 2 +- net/sunrpc/xprtsock.c | 2 +- net/tipc/socket.c | 2 +- net/unix/af_unix.c | 2 +- net/xfrm/xfrm_state.c | 2 +- 136 files changed, 304 insertions(+), 339 deletions(-)