From: "Paul E. McKenney" <paulmck@linux.ibm.com> To: "Joel Fernandes (Google)" <joel@joelfernandes.org> Cc: linux-kernel@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>, Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>, Bjorn Helgaas <bhelgaas@google.com>, Borislav Petkov <bp@alien8.de>, c0d1n61at3@gmail.com, "David S. Miller" <davem@davemloft.net>, edumazet@google.com, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>, "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>, Jonathan Corbet <corbet@lwn.net>, Josh Triplett <josh@joshtriplett.org>, keescook@chromium.org, kernel-hardening@lists.openwall.com, kernel-team@android.com, Lai Jiangshan <jiangshanlai@gmail.com>, Len Brown <lenb@kernel.org>, linux-acpi@vger.kernel.org, linux-doc@vger.kernel.org, linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, neilb@suse.com, netdev@vger.kernel.org, Pavel Machek <pavel@ucw.cz>, peterz@infradead.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Rasmus Villemoes <rasmus.villemoes@prevas.dk>, rcu@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>, Tejun Heo <tj@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, will@kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org> Subject: Re: [PATCH v2 3/9] rcu/sync: Remove custom check for reader-section Date: Tue, 16 Jul 2019 11:26:42 -0700 Message-ID: <20190716182642.GB22819@linux.ibm.com> (raw) In-Reply-To: <20190712170024.111093-4-joel@joelfernandes.org> On Fri, Jul 12, 2019 at 01:00:18PM -0400, Joel Fernandes (Google) wrote: > The rcu/sync code was doing its own check whether we are in a reader > section. With RCU consolidating flavors and the generic helper added in > this series, this is no longer need. We can just use the generic helper > and it results in a nice cleanup. > > Cc: Oleg Nesterov <oleg@redhat.com> > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> This needs to be forward-ported to current mainline. (Or, I believe equivalently for this file, to branch "dev" of -rcu.) Especially given that you have Oleg's Ack, I would be happy to take the forward-ported version. Thanx, Paul > --- > Please note: Only build and boot tested this particular patch so far. > > include/linux/rcu_sync.h | 5 ++--- > kernel/rcu/sync.c | 22 ---------------------- > 2 files changed, 2 insertions(+), 25 deletions(-) > > diff --git a/include/linux/rcu_sync.h b/include/linux/rcu_sync.h > index 6fc53a1345b3..c954f1efc919 100644 > --- a/include/linux/rcu_sync.h > +++ b/include/linux/rcu_sync.h > @@ -39,9 +39,8 @@ extern void rcu_sync_lockdep_assert(struct rcu_sync *); > */ > static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) > { > -#ifdef CONFIG_PROVE_RCU > - rcu_sync_lockdep_assert(rsp); > -#endif > + RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(), > + "suspicious rcu_sync_is_idle() usage"); > return !rsp->gp_state; /* GP_IDLE */ > } > > diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c > index a8304d90573f..535e02601f56 100644 > --- a/kernel/rcu/sync.c > +++ b/kernel/rcu/sync.c > @@ -10,37 +10,25 @@ > #include <linux/rcu_sync.h> > #include <linux/sched.h> > > -#ifdef CONFIG_PROVE_RCU > -#define __INIT_HELD(func) .held = func, > -#else > -#define __INIT_HELD(func) > -#endif > - > static const struct { > void (*sync)(void); > void (*call)(struct rcu_head *, void (*)(struct rcu_head *)); > void (*wait)(void); > -#ifdef CONFIG_PROVE_RCU > - int (*held)(void); > -#endif > } gp_ops[] = { > [RCU_SYNC] = { > .sync = synchronize_rcu, > .call = call_rcu, > .wait = rcu_barrier, > - __INIT_HELD(rcu_read_lock_held) > }, > [RCU_SCHED_SYNC] = { > .sync = synchronize_rcu, > .call = call_rcu, > .wait = rcu_barrier, > - __INIT_HELD(rcu_read_lock_sched_held) > }, > [RCU_BH_SYNC] = { > .sync = synchronize_rcu, > .call = call_rcu, > .wait = rcu_barrier, > - __INIT_HELD(rcu_read_lock_bh_held) > }, > }; > > @@ -49,16 +37,6 @@ enum { CB_IDLE = 0, CB_PENDING, CB_REPLAY }; > > #define rss_lock gp_wait.lock > > -#ifdef CONFIG_PROVE_RCU > -void rcu_sync_lockdep_assert(struct rcu_sync *rsp) > -{ > - RCU_LOCKDEP_WARN(!gp_ops[rsp->gp_type].held(), > - "suspicious rcu_sync_is_idle() usage"); > -} > - > -EXPORT_SYMBOL_GPL(rcu_sync_lockdep_assert); > -#endif > - > /** > * rcu_sync_init() - Initialize an rcu_sync structure > * @rsp: Pointer to rcu_sync structure to be initialized > -- > 2.22.0.510.g264f2c817a-goog >
next prev parent reply index Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-07-12 17:00 [PATCH v2 0/9] Harden list_for_each_entry_rcu() and family Joel Fernandes (Google) 2019-07-12 17:00 ` [PATCH v2 1/9] rcu/update: Remove useless check for debug_locks Joel Fernandes (Google) 2019-07-12 17:00 ` [PATCH v2 2/9] rcu: Add support for consolidated-RCU reader checking Joel Fernandes (Google) 2019-07-16 18:22 ` Paul E. McKenney 2019-07-16 18:35 ` Joel Fernandes 2019-07-16 18:50 ` Paul E. McKenney 2019-07-12 17:00 ` [PATCH v2 3/9] rcu/sync: Remove custom check for reader-section Joel Fernandes (Google) 2019-07-12 21:35 ` Joel Fernandes 2019-07-12 23:32 ` Paul E. McKenney 2019-07-13 3:01 ` Joel Fernandes 2019-07-13 3:10 ` Joel Fernandes 2019-07-13 8:21 ` Paul E. McKenney 2019-07-13 13:30 ` Joel Fernandes 2019-07-13 14:41 ` Paul E. McKenney 2019-07-13 15:36 ` Joel Fernandes 2019-07-13 15:50 ` Paul E. McKenney 2019-07-13 16:13 ` Joel Fernandes 2019-07-13 21:28 ` Paul E. McKenney 2019-07-14 18:10 ` Joel Fernandes 2019-07-14 18:38 ` Joel Fernandes 2019-07-14 18:50 ` Paul E. McKenney 2019-07-15 7:26 ` Oleg Nesterov 2019-07-16 18:26 ` Paul E. McKenney [this message] 2019-07-16 18:28 ` Paul E. McKenney 2019-07-12 17:00 ` [PATCH v2 4/9] ipv4: add lockdep condition to fix for_each_entry Joel Fernandes (Google) 2019-07-12 17:00 ` [PATCH v2 5/9] driver/core: Convert to use built-in RCU list checking Joel Fernandes (Google) 2019-07-12 17:00 ` [PATCH v2 6/9] workqueue: Convert for_each_wq to use built-in list check Joel Fernandes (Google) 2019-07-12 17:00 ` [PATCH v2 7/9] x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator Joel Fernandes (Google) 2019-07-12 17:00 ` [PATCH v2 8/9] acpi: Use built-in RCU list checking for acpi_ioremaps list Joel Fernandes (Google) 2019-07-12 17:00 ` [PATCH v2 9/9] doc: Update documentation about list_for_each_entry_rcu Joel Fernandes (Google)
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